D
Don@True-Cal
Wed, Aug 27, 2014 4:26 PM
Randy,
Sorry for the two graphs being at different scales so just be sure to readjust your reference. I like to think in PPM terms so the first graph is +/- 5 PPM for the whole gray plot area while the second is +/- 1 PPM. The most extreme outliers on the first graph is +0.3 to -0.5 PPM so that would be <10.0 uV. The winter graph is +0.1 to -0.9 PPM and would be 10.0 uV. All referenced around 10.0 V.
Don
-----Original Message-----
From: volt-nuts [mailto:volt-nuts-bounces@febo.com] On Behalf Of Randy Evans
Sent: Wednesday, August 27, 2014 10:50 AM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] 732A and Prologix received
Don,
If I am reading your charts correctly, it looks like your system is cycling over an 7 uV range over several days in summer, similar to what I am seeing. I don't have air conditioning (Northern California) so I do get some pretty good temperature variations from day to night, but less inside the house.
I need to figure out how to share files in Dropbox since I don't have my own web site. Good idea.
thanks,
Randy
On Wed, Aug 27, 2014 at 7:40 AM, Don@True-Cal truecalservices@gmail.com
wrote:
I have included a link to an ~30-hour measurement run that I
consistently do that should give you some idea of expected measurement drift over time.
Virtually all of the measurement drift is due to the 3458A internal
temperature differences around the 7V reference caused by ambient
temperature change. The drift associated with the 732A is probably
about 2-magnitudes less at this ambient temp drift. In my situation,
the inferred ambient temperature is cycling with the home
air-conditioning. Note the initial calibration temperatures as well as
the ACal temperatures and where the 3458A is measuring exactly 10V
relative to those temperatures. My primary 732A has been powered
without loss for 4 years and >5 years before that. The 3458A is
Agilent (Loveland) Cal'ed yearly and is powered 24-7-365 except for
the occasional mains power loss. The graphical measurements is using a
homegrown Agilent VEE program. It is very helpful if not essential to get an HPIB interface setup so you can do long term graphical analysis.
The other link was done in winter time when the lab a few degrees cooler.
https://www.dropbox.com/s/8je482i3r0belqn/732A%20gold%20%26%203458A%20
gold%2032-hour%20Ref%20Test%208-21-2014.pdf?dl=0
https://www.dropbox.com/s/xv3l9py7tx6hyh7/HP%20732A%20gold%20%26%20345
8A%20gold%207-day%2010.0v%20Ref%20Test.pdf?dl=0
I hope these Dropbox links work internationally - I'm new to using
this sharing method.
Don Johnson
-----Original Message-----
From: volt-nuts [mailto:volt-nuts-bounces@febo.com] On Behalf Of
acbern@gmx.de
Sent: Wednesday, August 27, 2014 8:42 AM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] 732A and Prologix received
well, what you do is to measure the stability of the 3458a. 1ppm drift
though sounds much as overall short term average variation if your
temperature is stable and your 3458a is always on. probably the temp
is not stable, and that is what you see, amongst potentially some
other smaller drifts like emf. before every cycle you should do an
acal dcv, if you still see 10uv +/- drifts that then seems too much.
(one thing I need to add is that one of my 3458a, not yet modified to
have lower reference temperature, has drifts when switched on and off.
that is not so much the case with modified reference. but my
assumption re the above is that your meter is always on, as I said)
732a references et al do have small short term drifts, you can
determine them with a josephson element (these guys told me), but the 732a is certainly very stable short term compared to a 3458a.
my 732a e.g. has a drift of 0.2ppm per year.
Gesendet: Mittwoch, 27. August 2014 um 14:36 Uhr
Von: "Randy Evans" randyevans2688@gmail.com
An: "Discussion of precise voltage measurement" volt-nuts@febo.com
Betreff: Re: [volt-nuts] 732A and Prologix received
I forgot to mention that I reduced the number of measurements to 100
per set since I wasn't seeing much difference in the variance
between 100 and
1000 measurements and the 1000 measurement per set takes too long.
Randy
On Wed, Aug 27, 2014 at 5:13 AM, Randy Evans
randyevans2688@gmail.com
wrote:
I am doing multiple 100 measurements simply to characterize the
of the 3458A and 732A units I just bought. After about 10
measurement
over 2 days I am seeing a variance of about .5 uV for the 10V
output,
0.05 ppm. However, the mean varies over a range of 10 uV, or 1 ppm.
that sound reasonable/
Randy
On Tue, Aug 26, 2014 at 5:41 PM, acbern@gmx.de wrote:
hi randy,
just for curiosity, why doing 100 measurements at nplc 1000. is
this
sample a changing value?
when i am doing 10 measurements from a stable signal at nplc 100
(only there many subsequent measuremnts with statistics make
sense) I am
getting a stanard deviation below 0.1ppm.
in a 30 minute test cycle, i would also be concerned about drifts
unless the amb. temperature is really very stable (half a degree
adds about 0.25ppm at 10v)
thanks
Betreff: Re: [volt-nuts] 732A and Prologix received
Is there any way to tell when the function key routine is
case of taking multiple readings using the DEFKEY and MATH
don't see any indication when the routine is complete. In one
case, I am taking a 100 readings with NLPC set for 1000 so its
a
before it's complete, but i have to guess when it's done.
Thanks,
Randy
On Sun, Aug 24, 2014 at 6:04 PM, Randy Evans <
Bill,
I am trying to figure out the MATH function without much
the sequence you said (I looked up the instructions to
understand
did - seems logical), BLUE DEFKEY BLUE F1 MATH 14;NRDGS
40;TRIG
it shows up on the display when I input BLUE F1. I hit ENTER
and
the 40 measurements and the MATH symbol shows on the display
measurements. After the SMPL symbol no longer blinks I hit
MATH 2
get a MATH ERR symbol on the display. I tried it a couple of
same result so I am doing something wrong. Is there a better
explaining how to do front panel masurements than the User
Guide,
seems oriented at programming automatic rather than manual
Randy:
The MATH function is accessible from the keypad. I
don't
interface right now that works. You can also program the
numeric
keys to have preprogrammed functions. DEFKEY
I have made my own "low thermal" measurement leads from
banana plugs and Belden #9272 wire. Why 9272, because it
was
time. It is tin plated copper, shielded twisted pair 20 ga.
I
to do custom cables with 16 ga. bare copper wire that I will
then
put a braided shield over it. I simply cannot find what I
want
build my own cable. I have done something like this before
and
fine. When I get a "round toit".
I have 6 ea. Pomona 1756-48 spade lug low thermal leads
that
used
in the past to verify my homemade "low thermal" leads as
Frankly I cannot see any difference between using the 1756
cables
homemade cables once I give them a few minutes for the
thermals
away.
As far as I can tell and measure the differences, if any,
are
ppm
at 10 volts.
Since the 10 volt, 1.0 volt and 1.018 volt outputs on
the
adjustable you may be seeing a misadjusted 1 volt from the
as
the instability of the readings it is hard to determine
which is
the
problem. I have programed (DEFKEY) a numeric keypad key #1
with
following code. "MATH 14;NRDGS 40;TRIG 4;TRIG ;" So what this
set
the MATH to "Statistics" (store high reading/low reading/
and
readings) in the registers, the number of readings to "40",
the
"hold" (which keeps the meter from triggering until I press
then
trigger the sequence of 40 readings when I push the "ENTER"
can
do all of this manually from the keypads but since I use
this
lot
I have preprogrammed it. This is after I set digits to "8"
and
Once those 40 readings are finished then you can access the
statistic registers, using the menu, by entering "MATH" and
then
low, a 4 for mean, and 13 for high. Of course you could do
all
through the IEEE also. The 3458A has a very rich set of
commands. I am still learning all of them. It depends upon
trying to accomplish.
Since the 1.018 and 1.0 volt outputs are passive and
derived
resistive dividers from the 10 volt, I don't see how they
could
to the varying readings you are measuring. I think I would
put a
the input of the 3458A and manually set the range to 1 volt
and
observe
the variations that way without the 732A involved. When I
do
variation from low reading to high reading of 0.125 uVolts
and
another
40 I get 0.155 uVolts. This is without the GUARD connected
to
side
of the measurment terminals, GUARD connected doesn't seem to
readings. So that is the base noise of the 3458A without
the
somewhere below .2uVolts. When hooked up to the 732A 1.0
volt
got
a variation of 0.159 uVolts using the same 40 reading method
would
use this to determine where your problem might exist. Just
meter
input shorted will point you in the right direction. Meter,
732A.
Sorry for the long dissertation. Friends get mad at me
for
detailed sometimes.
Bill
----- Original Message -----
From: "Randy Evans" randyevans2688@gmail.com
To: "Discussion of precise voltage measurement" <
Sent: Sunday, August 24, 2014 7:22 AM
Subject: Re: [volt-nuts] 732A and Prologix received
Bill,
I have convinced myself that the problem I an seeing is
due to
If I move the cables (with gold-plated banana plugs)
using a
rather than letting my hand touch the plugs, it is much
more
then hold the banana plug with my hand after the reading
has
the reading drifts rapidly upward. I am trying to check
the
the reading but I haven't figured out the MATH function
yet. I
is a programmed function using GPIB only?
The stability I am seeing by manually recording readings
(using
and 1000) is much greater than what you are measuring on
your
sure how to ascertain if it's the 3458A or the 732. The
value
readings are very different between the two - the 3458
reads
high on the 10 V output and about 12 uV low on the 1V output.
differences (this is after an ACAL). I need to find some
make sure the errors are not due to thermals again.
Randy
On Sat, Aug 23, 2014 at 10:21 AM, Bill Gold <
Randy:
I get 6 volt 4 amp/hr (or 4.5 amp/hr) batteries and
they
perfect. Power Sonic PS-640, Genesis NP4-6, Panasonic
others
that are in this size and package. Order from one of
the
distributors like Allied, Mouser, Digikey. This is a
very
as
it is used in a lot of "EXIT" signs so they are lighted
when
out. I don't see how the 12V 7AH will fit as they are
too
you could use a 12V 5AH (PS1250) as it is the same size
as 2
but the terminals are in the wrong place so you will
have to
the aluminum plate that holds them in the 732A battery pack.
be
careful if you use the 12v 5AH as you will have 4 extra
leads to deal with and connect correctly. I would stick
with
New batteries will last around 12 to 14 hours before the
out when AC power is not applied. So shipping to Cal
Lab
if it is a distance away, or you have to use a shipper
like
and
you ship the night before and then use their "Morning
Lab is expecting your 732A. Same on the way back to
you. Of
could always strap another battery on the 732A and hook
it
power" plug to last longer. I have seen it done. The
issue
Cal Lab to charge the extra battery before they ship the
732A
When you remove and work on the battery pack always
have
plugged in. The "CAL" led will stay on because the 18.6
v
is working.
The "CAL" light is to indicate that power has not
been
Reference Amp or other associated circuits. When the
raw
voltage drops below about 21 volts the "CAL" light will
go
voltage the heater circuits will not work correctly and
the
regulated supply will not regulate. The requirement is
that
Amp be kept "alive" at all times to maintain the output
measured at the time of the most recent Calibration or
the semiconductor junctions are unbiased and cool off
when
and then power is restored the result will be a
different 10
before the power failure. My experience is that after
all
that
these units have been powered up, this won't happen and
when
and then restored, even months later, the 732A will come
exactly the same 10 volts as when they lost power,
usually
after 24 hours of "warm up".
What type of hookup leads are you using when
measuring
output? What is the PLC set to? I always use 100 PLC
to
you don't have "low thermal" connection leads you can
for a minute or more after plugging in the leads due to
the
generated because of the difference in temperature
between
on the 732A and the banana plugs of the leads. I have
found
plugging in the lead will generate a thermal difference
difference of temps and some heating due to the physical
act
inserting the plug because of friction between the jack
and
at any rate). You have to allow at least a minute or
more
able
to make a measurement after plugging in the leads. I
just
variation of the 1 volt output of my 732A and using my
3458A
total difference of 0.159 uV over 40 measurements using
100
volt range of the 3458A. Using the MATH function and
all of
can collect. That was after waiting for several minutes
the leads.
I hope all of this helps.
Bill
----- Original Message -----
From: "Randy Evans" randyevans2688@gmail.com
To: "Discussion of precise voltage measurement" <
Sent: Friday, August 22, 2014 9:03 PM
Subject: Re: [volt-nuts] 732A and Prologix received
Todd,
Thanks for the info. I have several Panasonic 12V 7
AH
keep topped off and they have very low current draw
(~2 to
VDC) when charged and at their float voltage, so I am
in good condition. I will look at getting those in
the
ascertain the condition of the 732.
So now I have a what appears to be a functioning 3458A
and
slightly disagree. I am like the man with two watches
that
time - which is correct? For the moment, i am only
stability. The need for absolute accuracy will come later.
Randy
On Fri, Aug 22, 2014 at 8:06 PM, Todd Micallef <
Randy,
You have two possible choices. It can be configured
with
batteries or 2 x 12v 7Ah batteries. Hopefully the
modified the battery pack already. A couple of mine
to remove enough of the aluminum cover that fits
over the
batteries. The original cover will short out to the
of the battery configuration if this is not done.
You can find larger capacity batteries that will
give you
battery life. I lost a couple sets of mail-order
extended outages. I would recommend going with
locally
instead of the cheaper mail order. My local
Batteries
have some warranty if I remember correctly. Moving
2 12v batteries and pre-charge them on a battery
charger
before putting them in the 732A. I think the cheap
discharge equally, and would not recover when power
was
Inspect the back plane for damaged traces and look
at the
a few that looked questionable. So far, I have
replaced
the pre-regulator and regulator boards. My feeling
is
online, they should run as long as possible between
The battery charger circuit may need adjusting. I
tweaked
seemed to work fine.
Todd
On Fri, Aug 22, 2014 at 10:42 PM, Randy Evans <
I received my Fluke 732A today. Just powered it
up
batteries. Any suggestions for sources (I haven't
I want to make sure it works before doing that).
Also
ProLogix USB-GPIB adapter. I plan on using Mark Sims'
program to get the CAL data from my 3458A. Should
be a
and follow the instructions there.
and follow the instructions there.
and follow the instructions there.
and follow the instructions there.
and follow the instructions there.
Randy,
Sorry for the two graphs being at different scales so just be sure to readjust your reference. I like to think in PPM terms so the first graph is +/- 5 PPM for the whole gray plot area while the second is +/- 1 PPM. The most extreme outliers on the first graph is +0.3 to -0.5 PPM so that would be <10.0 uV. The winter graph is +0.1 to -0.9 PPM and would be 10.0 uV. All referenced around 10.0 V.
Don
-----Original Message-----
From: volt-nuts [mailto:volt-nuts-bounces@febo.com] On Behalf Of Randy Evans
Sent: Wednesday, August 27, 2014 10:50 AM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] 732A and Prologix received
Don,
If I am reading your charts correctly, it looks like your system is cycling over an 7 uV range over several days in summer, similar to what I am seeing. I don't have air conditioning (Northern California) so I do get some pretty good temperature variations from day to night, but less inside the house.
I need to figure out how to share files in Dropbox since I don't have my own web site. Good idea.
thanks,
Randy
On Wed, Aug 27, 2014 at 7:40 AM, Don@True-Cal <truecalservices@gmail.com>
wrote:
> I have included a link to an ~30-hour measurement run that I
> consistently do that should give you some idea of expected measurement drift over time.
> Virtually all of the measurement drift is due to the 3458A internal
> temperature differences around the 7V reference caused by ambient
> temperature change. The drift associated with the 732A is probably
> about 2-magnitudes less at this ambient temp drift. In my situation,
> the inferred ambient temperature is cycling with the home
> air-conditioning. Note the initial calibration temperatures as well as
> the ACal temperatures and where the 3458A is measuring exactly 10V
> relative to those temperatures. My primary 732A has been powered
> without loss for 4 years and >5 years before that. The 3458A is
> Agilent (Loveland) Cal'ed yearly and is powered 24-7-365 except for
> the occasional mains power loss. The graphical measurements is using a
> homegrown Agilent VEE program. It is very helpful if not essential to get an HPIB interface setup so you can do long term graphical analysis.
>
> The other link was done in winter time when the lab a few degrees cooler.
>
>
> https://www.dropbox.com/s/8je482i3r0belqn/732A%20gold%20%26%203458A%20
> gold%2032-hour%20Ref%20Test%208-21-2014.pdf?dl=0
>
>
> https://www.dropbox.com/s/xv3l9py7tx6hyh7/HP%20732A%20gold%20%26%20345
> 8A%20gold%207-day%2010.0v%20Ref%20Test.pdf?dl=0
>
> I hope these Dropbox links work internationally - I'm new to using
> this sharing method.
>
> Don Johnson
>
> -----Original Message-----
> From: volt-nuts [mailto:volt-nuts-bounces@febo.com] On Behalf Of
> acbern@gmx.de
> Sent: Wednesday, August 27, 2014 8:42 AM
> To: Discussion of precise voltage measurement
> Subject: Re: [volt-nuts] 732A and Prologix received
>
> well, what you do is to measure the stability of the 3458a. 1ppm drift
> though sounds much as overall short term average variation if your
> temperature is stable and your 3458a is always on. probably the temp
> is not stable, and that is what you see, amongst potentially some
> other smaller drifts like emf. before every cycle you should do an
> acal dcv, if you still see 10uv +/- drifts that then seems too much.
> (one thing I need to add is that one of my 3458a, not yet modified to
> have lower reference temperature, has drifts when switched on and off.
> that is not so much the case with modified reference. but my
> assumption re the above is that your meter is always on, as I said)
> 732a references et al do have small short term drifts, you can
> determine them with a josephson element (these guys told me), but the 732a is certainly very stable short term compared to a 3458a.
> my 732a e.g. has a drift of 0.2ppm per year.
>
>
> > Gesendet: Mittwoch, 27. August 2014 um 14:36 Uhr
> > Von: "Randy Evans" <randyevans2688@gmail.com>
> > An: "Discussion of precise voltage measurement" <volt-nuts@febo.com>
> > Betreff: Re: [volt-nuts] 732A and Prologix received
> >
> > I forgot to mention that I reduced the number of measurements to 100
> > per set since I wasn't seeing much difference in the variance
> > between 100 and
> > 1000 measurements and the 1000 measurement per set takes too long.
> >
> > Randy
> >
> >
> > On Wed, Aug 27, 2014 at 5:13 AM, Randy Evans
> > <randyevans2688@gmail.com>
> > wrote:
> >
> > > I am doing multiple 100 measurements simply to characterize the
> stability
> > > of the 3458A and 732A units I just bought. After about 10
> > > measurement
> sets
> > > over 2 days I am seeing a variance of about .5 uV for the 10V
> > > output,
> or
> > > 0.05 ppm. However, the mean varies over a range of 10 uV, or 1 ppm.
> Does
> > > that sound reasonable/
> > >
> > > Randy
> > >
> > >
> > > On Tue, Aug 26, 2014 at 5:41 PM, <acbern@gmx.de> wrote:
> > >
> > >> hi randy,
> > >>
> > >> just for curiosity, why doing 100 measurements at nplc 1000. is
> > >> this
> to
> > >> sample a changing value?
> > >> when i am doing 10 measurements from a stable signal at nplc 100
> > >> (only there many subsequent measuremnts with statistics make
> > >> sense) I am
> already
> > >> getting a stanard deviation below 0.1ppm.
> > >> in a 30 minute test cycle, i would also be concerned about drifts
> (acal)
> > >> unless the amb. temperature is really very stable (half a degree
> already
> > >> adds about 0.25ppm at 10v)
> > >>
> > >> thanks
> > >>
> > >>
> > >>
> > >>
> > >> > Gesendet: Dienstag, 26. August 2014 um 04:23 Uhr
> > >> > Von: "Randy Evans" <randyevans2688@gmail.com>
> > >> > An: "Discussion of precise voltage measurement"
> > >> > <volt-nuts@febo.com
> >
> > >> > Betreff: Re: [volt-nuts] 732A and Prologix received
> > >> >
> > >> > Is there any way to tell when the function key routine is
> complete? In
> > >> the
> > >> > case of taking multiple readings using the DEFKEY and MATH
> function, I
> > >> > don't see any indication when the routine is complete. In one
> > >> particular
> > >> > case, I am taking a 100 readings with NLPC set for 1000 so its
> > >> > a
> long
> > >> while
> > >> > before it's complete, but i have to guess when it's done.
> > >> >
> > >> > Thanks,
> > >> >
> > >> > Randy
> > >> >
> > >> >
> > >> > On Sun, Aug 24, 2014 at 6:04 PM, Randy Evans <
> randyevans2688@gmail.com>
> > >> > wrote:
> > >> >
> > >> > > Bill,
> > >> > >
> > >> > > I am trying to figure out the MATH function without much
> success. I
> > >> input
> > >> > > the sequence you said (I looked up the instructions to
> > >> > > understand
> > >> what you
> > >> > > did - seems logical), BLUE DEFKEY BLUE F1 MATH 14;NRDGS
> > >> > > 40;TRIG
> > >> 4;TRIG; and
> > >> > > it shows up on the display when I input BLUE F1. I hit ENTER
> > >> > > and
> it
> > >> takes
> > >> > > the 40 measurements and the MATH symbol shows on the display
> during
> > >> the
> > >> > > measurements. After the SMPL symbol no longer blinks I hit
> > >> > > MATH 2
> > >> and I
> > >> > > get a MATH ERR symbol on the display. I tried it a couple of
> times
> > >> and the
> > >> > > same result so I am doing something wrong. Is there a better
> source
> > >> for
> > >> > > explaining how to do front panel masurements than the User
> > >> > > Guide,
> > >> which
> > >> > > seems oriented at programming automatic rather than manual
> > >> measurements.
> > >> > >
> > >> > > Randy
> > >> > >
> > >> > >
> > >> > >
> > >> > > On Sun, Aug 24, 2014 at 4:46 PM, Bill Gold
> > >> > > <wpgold3637@att.net>
> > >> wrote:
> > >> > >
> > >> > >> Randy:
> > >> > >>
> > >> > >> The MATH function is accessible from the keypad. I
> > >> > >> don't
> have
> > >> an IEEE
> > >> > >> interface right now that works. You can also program the
> > >> > >> numeric
> > >> keypad
> > >> > >> keys to have preprogrammed functions. DEFKEY
> > >> > >>
> > >> > >> I have made my own "low thermal" measurement leads from
> Pomona
> > >> #4892
> > >> > >> banana plugs and Belden #9272 wire. Why 9272, because it
> > >> > >> was
> handy
> > >> at the
> > >> > >> time. It is tin plated copper, shielded twisted pair 20 ga.
> > >> > >> I
> have
> > >> plans
> > >> > >> to do custom cables with 16 ga. bare copper wire that I will
> twist
> > >> and
> > >> > >> then
> > >> > >> put a braided shield over it. I simply cannot find what I
> > >> > >> want
> so I
> > >> will
> > >> > >> build my own cable. I have done something like this before
> > >> > >> and
> it
> > >> worked
> > >> > >> fine. When I get a "round toit".
> > >> > >>
> > >> > >> I have 6 ea. Pomona 1756-48 spade lug low thermal leads
> > >> > >> that
> I
> > >> have
> > >> > >> used
> > >> > >> in the past to verify my homemade "low thermal" leads as
> described
> > >> above.
> > >> > >> Frankly I cannot see any difference between using the 1756
> > >> > >> cables
> > >> and my
> > >> > >> homemade cables once I give them a few minutes for the
> > >> > >> thermals
> to go
> > >> > >> away.
> > >> > >> As far as I can tell and measure the differences, if any,
> > >> > >> are
> below
> > >> 0.1
> > >> > >> ppm
> > >> > >> at 10 volts.
> > >> > >>
> > >> > >> Since the 10 volt, 1.0 volt and 1.018 volt outputs on
> > >> > >> the
> 732A
> > >> are all
> > >> > >> adjustable you may be seeing a misadjusted 1 volt from the
> 732A. As
> > >> far
> > >> > >> as
> > >> > >> the instability of the readings it is hard to determine
> > >> > >> which is
> > >> causing
> > >> > >> the
> > >> > >> problem. I have programed (DEFKEY) a numeric keypad key #1
> > >> > >> with
> the
> > >> > >> following code. "MATH 14;NRDGS 40;TRIG 4;TRIG ;" So what this
> > >> does is
> > >> > >> set
> > >> > >> the MATH to "Statistics" (store high reading/low reading/
> > >> > >> and
> mean
> > >> of the
> > >> > >> readings) in the registers, the number of readings to "40",
> > >> > >> the
> > >> trigger to
> > >> > >> "hold" (which keeps the meter from triggering until I press
> "ENTER"
> > >> and
> > >> > >> then
> > >> > >> trigger the sequence of 40 readings when I push the "ENTER"
> button.
> > >> You
> > >> > >> can
> > >> > >> do all of this manually from the keypads but since I use
> > >> > >> this
> > >> sequence a
> > >> > >> lot
> > >> > >> I have preprogrammed it. This is after I set digits to "8"
> > >> > >> and
> PLC
> > >> to
> > >> > >> 100.
> > >> > >> Once those 40 readings are finished then you can access the
> various
> > >> MATH
> > >> > >> statistic registers, using the menu, by entering "MATH" and
> > >> > >> then
> a 2
> > >> for
> > >> > >> low, a 4 for mean, and 13 for high. Of course you could do
> > >> > >> all
> of
> > >> this
> > >> > >> through the IEEE also. The 3458A has a very rich set of
> measurement
> > >> > >> commands. I am still learning all of them. It depends upon
> what I
> > >> am
> > >> > >> trying to accomplish.
> > >> > >>
> > >> > >> Since the 1.018 and 1.0 volt outputs are passive and
> > >> > >> derived
> from
> > >> > >> resistive dividers from the 10 volt, I don't see how they
> > >> > >> could
> > >> contribute
> > >> > >> to the varying readings you are measuring. I think I would
> > >> > >> put a
> > >> short on
> > >> > >> the input of the 3458A and manually set the range to 1 volt
> > >> > >> and
> then
> > >> > >> observe
> > >> > >> the variations that way without the 732A involved. When I
> > >> > >> do
> this I
> > >> see a
> > >> > >> variation from low reading to high reading of 0.125 uVolts
> > >> > >> and
> then
> > >> > >> another
> > >> > >> 40 I get 0.155 uVolts. This is without the GUARD connected
> > >> > >> to
> the
> > >> low
> > >> > >> side
> > >> > >> of the measurment terminals, GUARD connected doesn't seem to
> affect
> > >> the
> > >> > >> readings. So that is the base noise of the 3458A without
> > >> > >> the
> 732A,
> > >> > >> somewhere below .2uVolts. When hooked up to the 732A 1.0
> > >> > >> volt
> > >> output I
> > >> > >> got
> > >> > >> a variation of 0.159 uVolts using the same 40 reading method
> above.
> > >> I
> > >> > >> would
> > >> > >> use this to determine where your problem might exist. Just
> having
> > >> the
> > >> > >> meter
> > >> > >> input shorted will point you in the right direction. Meter,
> cables
> > >> or
> > >> > >> 732A.
> > >> > >>
> > >> > >> Sorry for the long dissertation. Friends get mad at me
> > >> > >> for
> > >> being so
> > >> > >> detailed sometimes.
> > >> > >>
> > >> > >> Bill
> > >> > >>
> > >> > >> ----- Original Message -----
> > >> > >> From: "Randy Evans" <randyevans2688@gmail.com>
> > >> > >> To: "Discussion of precise voltage measurement" <
> volt-nuts@febo.com>
> > >> > >> Sent: Sunday, August 24, 2014 7:22 AM
> > >> > >> Subject: Re: [volt-nuts] 732A and Prologix received
> > >> > >>
> > >> > >>
> > >> > >> > Bill,
> > >> > >> >
> > >> > >> > I have convinced myself that the problem I an seeing is
> > >> > >> > due to
> > >> thermals.
> > >> > >> > If I move the cables (with gold-plated banana plugs)
> > >> > >> > using a
> small
> > >> > >> towel
> > >> > >> > rather than letting my hand touch the plugs, it is much
> > >> > >> > more
> > >> stable.
> > >> > >> If I
> > >> > >> > then hold the banana plug with my hand after the reading
> > >> > >> > has
> > >> stabilized,
> > >> > >> > the reading drifts rapidly upward. I am trying to check
> > >> > >> > the
> > >> stability
> > >> > >> of
> > >> > >> > the reading but I haven't figured out the MATH function
> > >> > >> > yet. I
> > >> assume
> > >> > >> this
> > >> > >> > is a programmed function using GPIB only?
> > >> > >> >
> > >> > >> > The stability I am seeing by manually recording readings
> > >> > >> > (using
> > >> NLPC of
> > >> > >> 100
> > >> > >> > and 1000) is much greater than what you are measuring on
> > >> > >> > your
> > >> system.
> > >> > >> Not
> > >> > >> > sure how to ascertain if it's the 3458A or the 732. The
> > >> > >> > value
> of
> > >> the
> > >> > >> > readings are very different between the two - the 3458
> > >> > >> > reads
> about
> > >> 50 uV
> > >> > >> > high on the 10 V output and about 12 uV low on the 1V output.
> > >> Rather
> > >> > >> large
> > >> > >> > differences (this is after an ACAL). I need to find some
> better
> > >> cables
> > >> > >> to
> > >> > >> > make sure the errors are not due to thermals again.
> > >> > >> >
> > >> > >> > Randy
> > >> > >> >
> > >> > >> >
> > >> > >> > On Sat, Aug 23, 2014 at 10:21 AM, Bill Gold <
> wpgold3637@att.net>
> > >> wrote:
> > >> > >> >
> > >> > >> > > Randy:
> > >> > >> > >
> > >> > >> > > I get 6 volt 4 amp/hr (or 4.5 amp/hr) batteries and
> > >> > >> > > they
> > >> will fit
> > >> > >> > > perfect. Power Sonic PS-640, Genesis NP4-6, Panasonic
> > >> LC-R064R5C and
> > >> > >> > > others
> > >> > >> > > that are in this size and package. Order from one of
> > >> > >> > > the
> usual
> > >> > >> electronics
> > >> > >> > > distributors like Allied, Mouser, Digikey. This is a
> > >> > >> > > very
> common
> > >> > >> battery
> > >> > >> > > as
> > >> > >> > > it is used in a lot of "EXIT" signs so they are lighted
> > >> > >> > > when
> the
> > >> power
> > >> > >> goes
> > >> > >> > > out. I don't see how the 12V 7AH will fit as they are
> > >> > >> > > too
> > >> large. I
> > >> > >> guess
> > >> > >> > > you could use a 12V 5AH (PS1250) as it is the same size
> > >> > >> > > as 2
> x 6
> > >> volt
> > >> > >> 4
> > >> > >> AH
> > >> > >> > > but the terminals are in the wrong place so you will
> > >> > >> > > have to
> > >> "nibble"
> > >> > >> out
> > >> > >> > > the aluminum plate that holds them in the 732A battery pack.
> > >> You have
> > >> > >> to
> > >> > >> > > be
> > >> > >> > > careful if you use the 12v 5AH as you will have 4 extra
> battery
> > >> > >> connection
> > >> > >> > > leads to deal with and connect correctly. I would stick
> > >> > >> > > with
> > >> the 6V
> > >> > >> 4AH.
> > >> > >> > > New batteries will last around 12 to 14 hours before the
> "CAL"
> > >> light
> > >> > >> goes
> > >> > >> > > out when AC power is not applied. So shipping to Cal
> > >> > >> > > Lab
> can be
> > >> a
> > >> > >> problem
> > >> > >> > > if it is a distance away, or you have to use a shipper
> > >> > >> > > like
> UPS
> > >> or
> > >> > >> FEDEX
> > >> > >> > > and
> > >> > >> > > you ship the night before and then use their "Morning
> delivery"
> > >> and
> > >> > >> the
> > >> > >> Cal
> > >> > >> > > Lab is expecting your 732A. Same on the way back to
> > >> > >> > > you. Of
> > >> course
> > >> > >> you
> > >> > >> > > could always strap another battery on the 732A and hook
> > >> > >> > > it
> up to
> > >> the
> > >> > >> "ext
> > >> > >> > > power" plug to last longer. I have seen it done. The
> > >> > >> > > issue
> is
> > >> to get
> > >> > >> the
> > >> > >> > > Cal Lab to charge the extra battery before they ship the
> > >> > >> > > 732A
> > >> back to
> > >> > >> you.
> > >> > >> > >
> > >> > >> > > When you remove and work on the battery pack always
> > >> > >> > > have
> the
> > >> AC
> > >> > >> power
> > >> > >> > > plugged in. The "CAL" led will stay on because the 18.6
> > >> > >> > > v
> > >> regulated
> > >> > >> supply
> > >> > >> > > is working.
> > >> > >> > >
> > >> > >> > > The "CAL" light is to indicate that power has not
> > >> > >> > > been
> lost
> > >> to the
> > >> > >> > > Reference Amp or other associated circuits. When the
> > >> > >> > > raw
> supply
> > >> > >> (battery)
> > >> > >> > > voltage drops below about 21 volts the "CAL" light will
> > >> > >> > > go
> out.
> > >> Below
> > >> > >> that
> > >> > >> > > voltage the heater circuits will not work correctly and
> > >> > >> > > the
> 18.6
> > >> volt
> > >> > >> > > regulated supply will not regulate. The requirement is
> > >> > >> > > that
> the
> > >> > >> Reference
> > >> > >> > > Amp be kept "alive" at all times to maintain the output
> voltage
> > >> that
> > >> > >> was
> > >> > >> > > measured at the time of the most recent Calibration or
> > >> Certification.
> > >> > >> When
> > >> > >> > > the semiconductor junctions are unbiased and cool off
> > >> > >> > > when
> power
> > >> is
> > >> > >> lost,
> > >> > >> > > and then power is restored the result will be a
> > >> > >> > > different 10
> > >> volts
> > >> > >> than
> > >> > >> > > before the power failure. My experience is that after
> > >> > >> > > all
> of the
> > >> > >> years
> > >> > >> > > that
> > >> > >> > > these units have been powered up, this won't happen and
> > >> > >> > > when
> > >> power is
> > >> > >> lost
> > >> > >> > > and then restored, even months later, the 732A will come
> back to
> > >> > >> almost
> > >> > >> > > exactly the same 10 volts as when they lost power,
> > >> > >> > > usually
> with
> > >> in 0.2
> > >> > >> PPM
> > >> > >> > > after 24 hours of "warm up".
> > >> > >> > >
> > >> > >> > > What type of hookup leads are you using when
> > >> > >> > > measuring
> the 1
> > >> volt
> > >> > >> > > output? What is the PLC set to? I always use 100 PLC
> > >> > >> > > to
> measure
> > >> > >> this.
> > >> > >> If
> > >> > >> > > you don't have "low thermal" connection leads you can
> experience
> > >> uV
> > >> > >> changes
> > >> > >> > > for a minute or more after plugging in the leads due to
> > >> > >> > > the
> > >> "thermals"
> > >> > >> > > generated because of the difference in temperature
> > >> > >> > > between
> the
> > >> banana
> > >> > >> jacks
> > >> > >> > > on the 732A and the banana plugs of the leads. I have
> > >> > >> > > found
> > >> that even
> > >> > >> just
> > >> > >> > > plugging in the lead will generate a thermal difference
> because
> > >> of
> > >> > >> > > difference of temps and some heating due to the physical
> > >> > >> > > act
> of
> > >> just
> > >> > >> > > inserting the plug because of friction between the jack
> > >> > >> > > and
> plug
> > >> (my
> > >> > >> theory
> > >> > >> > > at any rate). You have to allow at least a minute or
> > >> > >> > > more
> before
> > >> > >> being
> > >> > >> > > able
> > >> > >> > > to make a measurement after plugging in the leads. I
> > >> > >> > > just
> > >> measured
> > >> > >> the
> > >> > >> > > variation of the 1 volt output of my 732A and using my
> > >> > >> > > 3458A
> and
> > >> I
> > >> > >> got a
> > >> > >> > > total difference of 0.159 uV over 40 measurements using
> > >> > >> > > 100
> PLC
> > >> on
> > >> > >> the
> > >> > >> 1
> > >> > >> > > volt range of the 3458A. Using the MATH function and
> > >> > >> > > all of
> the
> > >> data
> > >> > >> you
> > >> > >> > > can collect. That was after waiting for several minutes
> after
> > >> > >> plugging
> > >> > >> in
> > >> > >> > > the leads.
> > >> > >> > >
> > >> > >> > > I hope all of this helps.
> > >> > >> > >
> > >> > >> > > Bill
> > >> > >> > >
> > >> > >> > >
> > >> > >> > >
> > >> > >> > > ----- Original Message -----
> > >> > >> > > From: "Randy Evans" <randyevans2688@gmail.com>
> > >> > >> > > To: "Discussion of precise voltage measurement" <
> > >> volt-nuts@febo.com>
> > >> > >> > > Sent: Friday, August 22, 2014 9:03 PM
> > >> > >> > > Subject: Re: [volt-nuts] 732A and Prologix received
> > >> > >> > >
> > >> > >> > >
> > >> > >> > > > Todd,
> > >> > >> > > >
> > >> > >> > > > Thanks for the info. I have several Panasonic 12V 7
> > >> > >> > > > AH
> > >> batteries
> > >> > >> that
> > >> > >> I
> > >> > >> > > > keep topped off and they have very low current draw
> > >> > >> > > > (~2 to
> 3
> > >> mA at
> > >> > >> 13.5
> > >> > >> > > > VDC) when charged and at their float voltage, so I am
> pretty
> > >> sure
> > >> > >> they
> > >> > >> > > are
> > >> > >> > > > in good condition. I will look at getting those in
> > >> > >> > > > the
> units
> > >> after
> > >> > >> I
> > >> > >> > > > ascertain the condition of the 732.
> > >> > >> > > >
> > >> > >> > > > So now I have a what appears to be a functioning 3458A
> > >> > >> > > > and
> a
> > >> 732A
> > >> > >> but
> > >> > >> > > they
> > >> > >> > > > slightly disagree. I am like the man with two watches
> > >> > >> > > > that
> > >> disagree
> > >> > >> on
> > >> > >> > > the
> > >> > >> > > > time - which is correct? For the moment, i am only
> concerned
> > >> with
> > >> > >> > > > stability. The need for absolute accuracy will come later.
> > >> > >> > > >
> > >> > >> > > > Randy
> > >> > >> > > >
> > >> > >> > > >
> > >> > >> > > > On Fri, Aug 22, 2014 at 8:06 PM, Todd Micallef <
> > >> tmicallef@gmail.com
> > >> > >> >
> > >> > >> > > wrote:
> > >> > >> > > >
> > >> > >> > > > > Randy,
> > >> > >> > > > >
> > >> > >> > > > > You have two possible choices. It can be configured
> > >> > >> > > > > with
> 4 x
> > >> 6v
> > >> > >> 4Ah
> > >> > >> > > > > batteries or 2 x 12v 7Ah batteries. Hopefully the
> previous
> > >> owner
> > >> > >> has
> > >> > >> > > > > modified the battery pack already. A couple of mine
> needed a
> > >> > >> nibbler
> > >> > >> > > tool
> > >> > >> > > > > to remove enough of the aluminum cover that fits
> > >> > >> > > > > over the
> > >> tops of
> > >> > >> the
> > >> > >> > > > > batteries. The original cover will short out to the
> battery
> > >> tabs
> > >> > >> > > regardless
> > >> > >> > > > > of the battery configuration if this is not done.
> > >> > >> > > > >
> > >> > >> > > > > You can find larger capacity batteries that will
> > >> > >> > > > > give you
> > >> slightly
> > >> > >> more
> > >> > >> > > > > battery life. I lost a couple sets of mail-order
> batteries
> > >> after a
> > >> > >> few
> > >> > >> > > > > extended outages. I would recommend going with
> > >> > >> > > > > locally
> bought
> > >> > >> batteries
> > >> > >> > > > > instead of the cheaper mail order. My local
> > >> > >> > > > > Batteries
> Plus
> > >> will
> > >> > >> > > typically
> > >> > >> > > > > have some warranty if I remember correctly. Moving
> forward I
> > >> will
> > >> > >> only
> > >> > >> > > use
> > >> > >> > > > > 2 12v batteries and pre-charge them on a battery
> > >> > >> > > > > charger
> to
> > >> > >> equalize
> > >> > >> > > them
> > >> > >> > > > > before putting them in the 732A. I think the cheap
> batteries
> > >> did
> > >> > >> not
> > >> > >> > > > > discharge equally, and would not recover when power
> > >> > >> > > > > was
> > >> applied.
> > >> > >> > > > >
> > >> > >> > > > > Inspect the back plane for damaged traces and look
> > >> > >> > > > > at the
> > >> > >> capacitors. I
> > >> > >> > > had
> > >> > >> > > > > a few that looked questionable. So far, I have
> > >> > >> > > > > replaced
> all
> > >> the
> > >> > >> big
> > >> > >> > > caps
> > >> > >> > > on
> > >> > >> > > > > the pre-regulator and regulator boards. My feeling
> > >> > >> > > > > is
> that
> > >> once
> > >> > >> these
> > >> > >> > > go
> > >> > >> > > > > online, they should run as long as possible between
> repairs.
> > >> > >> > > > >
> > >> > >> > > > > The battery charger circuit may need adjusting. I
> > >> > >> > > > > tweaked
> > >> mine and
> > >> > >> it
> > >> > >> > > > > seemed to work fine.
> > >> > >> > > > >
> > >> > >> > > > > Todd
> > >> > >> > > > >
> > >> > >> > > > >
> > >> > >> > > > > On Fri, Aug 22, 2014 at 10:42 PM, Randy Evans <
> > >> > >> > > randyevans2688@gmail.com>
> > >> > >> > > > > wrote:
> > >> > >> > > > >
> > >> > >> > > > > > I received my Fluke 732A today. Just powered it
> > >> > >> > > > > > up
> but it
> > >> needs
> > >> > >> new
> > >> > >> > > > > > batteries. Any suggestions for sources (I haven't
> opened
> > >> up the
> > >> > >> unit
> > >> > >> > > > > yet -
> > >> > >> > > > > > I want to make sure it works before doing that).
> > >> > >> > > > > > Also
> > >> received
> > >> > >> the
> > >> > >> > > > > > ProLogix USB-GPIB adapter. I plan on using Mark Sims'
> CAL
> > >> ran
> > >> > >> data
> > >> > >> > > > > dumper
> > >> > >> > > > > > program to get the CAL data from my 3458A. Should
> > >> > >> > > > > > be a
> > >> busy
> > >> > >> weekend.
> > >> > >> > > > > >
> > >> > >> > > > > > Randy
> > >> > >> > > > > > _______________________________________________
> > >> > >> > > > > > volt-nuts mailing list -- volt-nuts@febo.com To
> > >> > >> > > > > > unsubscribe, go to
> > >> > >> > > > > >
> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> > >> > >> > > > > > and follow the instructions there.
> > >> > >> > > > > >
> > >> > >> > > > > _______________________________________________
> > >> > >> > > > > volt-nuts mailing list -- volt-nuts@febo.com To
> > >> > >> > > > > unsubscribe, go to
> > >> > >> > > > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-n
> > >> > >> > > > > uts and follow the instructions there.
> > >> > >> > > > >
> > >> > >> > > > _______________________________________________
> > >> > >> > > > volt-nuts mailing list -- volt-nuts@febo.com To
> > >> > >> > > > unsubscribe, go to
> > >> > >> > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> > >> > >> > > > and follow the instructions there.
> > >> > >> > >
> > >> > >> > > _______________________________________________
> > >> > >> > > volt-nuts mailing list -- volt-nuts@febo.com To
> > >> > >> > > unsubscribe, go to
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> > >> > >> > > and follow the instructions there.
> > >> > >> > >
> > >> > >> > _______________________________________________
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> > >> > >> > unsubscribe, go to
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> > >> > >>
> > >> > >> _______________________________________________
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> > >> > >> go to
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> > >> > >
> > >> > >
> > >> > _______________________________________________
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> > >> > to
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A
acbern@gmx.de
Wed, Aug 27, 2014 7:34 PM
hi randy,
the specified drift of the 3458a over your 38.1 to 40.3 (about 1k) is 1ppm +/- allone in the 10v range. thats 10uv. in other ranges its worse.
unless your 732a is very bad (very unlikely), you measure mostly the 3458a temp. drift. 1000nplc and 100 readings average do not make sense in that context. if your goal is to be at 0.01ppm additional gain error by using the nplc1000, you need to be sure your temp related drift is even below that. 0.01ppm of temp drift equates 20mk temp stability! you see that all this does not make much sense.
adrian
Gesendet: Mittwoch, 27. August 2014 um 15:37 Uhr
Von: "Randy Evans" randyevans2688@gmail.com
An: "Discussion of precise voltage measurement" volt-nuts@febo.com
Betreff: Re: [volt-nuts] 732A and Prologix received
The HP3458A and the Fluke 732A are on continuously and I do an ACAL at
least every few hours, or when the room temperature changes by more than 1
degree C. The total range of measurements is 10uV so the drift is +/-5uV,
or 0.5 ppm. The room temperature is not particularly stable and varies
over a 3C range. The internal temp of the 3458 varies from 38.1 to 40.3
degrees C over the set of measurements. The 732A thermistor resistance
measures from 3.6677 Kohms to 3.6686 Kohms. I am using copper wires
between the 3458A and the 752A to minimize thermals. At the moment I have
no way to tell which unit is drifting the most.
Randy
On Wed, Aug 27, 2014 at 6:41 AM, acbern@gmx.de wrote:
well, what you do is to measure the stability of the 3458a. 1ppm drift
though sounds much as overall short term average variation if your
temperature is stable and your 3458a is always on. probably the temp is not
stable, and that is what you see, amongst potentially some other smaller
drifts like emf. before every cycle you should do an acal dcv, if you still
see 10uv +/- drifts that then seems too much. (one thing I need to add is
that one of my 3458a, not yet modified to have lower reference temperature,
has drifts when switched on and off. that is not so much the case with
modified reference. but my assumption re the above is that your meter is
always on, as I said)
732a references et al do have small short term drifts, you can determine
them with a josephson element (these guys told me), but the 732a is
certainly very stable short term compared to a 3458a. my 732a e.g. has a
drift of 0.2ppm per year.
Gesendet: Mittwoch, 27. August 2014 um 14:36 Uhr
Von: "Randy Evans" randyevans2688@gmail.com
An: "Discussion of precise voltage measurement" volt-nuts@febo.com
Betreff: Re: [volt-nuts] 732A and Prologix received
I forgot to mention that I reduced the number of measurements to 100 per
set since I wasn't seeing much difference in the variance between 100 and
1000 measurements and the 1000 measurement per set takes too long.
Randy
On Wed, Aug 27, 2014 at 5:13 AM, Randy Evans randyevans2688@gmail.com
wrote:
I am doing multiple 100 measurements simply to characterize the
of the 3458A and 732A units I just bought. After about 10 measurement
over 2 days I am seeing a variance of about .5 uV for the 10V output,
0.05 ppm. However, the mean varies over a range of 10 uV, or 1 ppm.
that sound reasonable/
Randy
On Tue, Aug 26, 2014 at 5:41 PM, acbern@gmx.de wrote:
hi randy,
just for curiosity, why doing 100 measurements at nplc 1000. is this
sample a changing value?
when i am doing 10 measurements from a stable signal at nplc 100 (only
there many subsequent measuremnts with statistics make sense) I am
getting a stanard deviation below 0.1ppm.
in a 30 minute test cycle, i would also be concerned about drifts
unless the amb. temperature is really very stable (half a degree
adds about 0.25ppm at 10v)
thanks
Betreff: Re: [volt-nuts] 732A and Prologix received
Is there any way to tell when the function key routine is
case of taking multiple readings using the DEFKEY and MATH
don't see any indication when the routine is complete. In one
case, I am taking a 100 readings with NLPC set for 1000 so its a
before it's complete, but i have to guess when it's done.
Thanks,
Randy
On Sun, Aug 24, 2014 at 6:04 PM, Randy Evans <
Bill,
I am trying to figure out the MATH function without much
the sequence you said (I looked up the instructions to understand
did - seems logical), BLUE DEFKEY BLUE F1 MATH 14;NRDGS 40;TRIG
it shows up on the display when I input BLUE F1. I hit ENTER and
the 40 measurements and the MATH symbol shows on the display
measurements. After the SMPL symbol no longer blinks I hit MATH 2
get a MATH ERR symbol on the display. I tried it a couple of
same result so I am doing something wrong. Is there a better
explaining how to do front panel masurements than the User Guide,
seems oriented at programming automatic rather than manual
Randy:
The MATH function is accessible from the keypad. I don't
interface right now that works. You can also program the numeric
keys to have preprogrammed functions. DEFKEY
I have made my own "low thermal" measurement leads from
banana plugs and Belden #9272 wire. Why 9272, because it was
time. It is tin plated copper, shielded twisted pair 20 ga. I
to do custom cables with 16 ga. bare copper wire that I will
then
put a braided shield over it. I simply cannot find what I want
build my own cable. I have done something like this before and
fine. When I get a "round toit".
I have 6 ea. Pomona 1756-48 spade lug low thermal leads that
used
in the past to verify my homemade "low thermal" leads as
Frankly I cannot see any difference between using the 1756 cables
homemade cables once I give them a few minutes for the thermals
away.
As far as I can tell and measure the differences, if any, are
ppm
at 10 volts.
Since the 10 volt, 1.0 volt and 1.018 volt outputs on the
adjustable you may be seeing a misadjusted 1 volt from the
as
the instability of the readings it is hard to determine which is
the
problem. I have programed (DEFKEY) a numeric keypad key #1 with
following code. "MATH 14;NRDGS 40;TRIG 4;TRIG ;" So what this
set
the MATH to "Statistics" (store high reading/low reading/ and
readings) in the registers, the number of readings to "40", the
"hold" (which keeps the meter from triggering until I press
then
trigger the sequence of 40 readings when I push the "ENTER"
can
do all of this manually from the keypads but since I use this
lot
I have preprogrammed it. This is after I set digits to "8" and
Once those 40 readings are finished then you can access the
statistic registers, using the menu, by entering "MATH" and then
low, a 4 for mean, and 13 for high. Of course you could do all
through the IEEE also. The 3458A has a very rich set of
commands. I am still learning all of them. It depends upon
trying to accomplish.
Since the 1.018 and 1.0 volt outputs are passive and derived
resistive dividers from the 10 volt, I don't see how they could
to the varying readings you are measuring. I think I would put a
the input of the 3458A and manually set the range to 1 volt and
observe
the variations that way without the 732A involved. When I do
variation from low reading to high reading of 0.125 uVolts and
another
40 I get 0.155 uVolts. This is without the GUARD connected to
side
of the measurment terminals, GUARD connected doesn't seem to
readings. So that is the base noise of the 3458A without the
somewhere below .2uVolts. When hooked up to the 732A 1.0 volt
got
a variation of 0.159 uVolts using the same 40 reading method
would
use this to determine where your problem might exist. Just
meter
input shorted will point you in the right direction. Meter,
732A.
Sorry for the long dissertation. Friends get mad at me for
detailed sometimes.
Bill
----- Original Message -----
From: "Randy Evans" randyevans2688@gmail.com
To: "Discussion of precise voltage measurement" <
Sent: Sunday, August 24, 2014 7:22 AM
Subject: Re: [volt-nuts] 732A and Prologix received
Bill,
I have convinced myself that the problem I an seeing is due to
If I move the cables (with gold-plated banana plugs) using a
rather than letting my hand touch the plugs, it is much more
then hold the banana plug with my hand after the reading has
the reading drifts rapidly upward. I am trying to check the
the reading but I haven't figured out the MATH function yet. I
is a programmed function using GPIB only?
The stability I am seeing by manually recording readings (using
and 1000) is much greater than what you are measuring on your
sure how to ascertain if it's the 3458A or the 732. The value
readings are very different between the two - the 3458 reads
high on the 10 V output and about 12 uV low on the 1V output.
differences (this is after an ACAL). I need to find some
make sure the errors are not due to thermals again.
Randy
On Sat, Aug 23, 2014 at 10:21 AM, Bill Gold <
Randy:
I get 6 volt 4 amp/hr (or 4.5 amp/hr) batteries and they
perfect. Power Sonic PS-640, Genesis NP4-6, Panasonic
others
that are in this size and package. Order from one of the
distributors like Allied, Mouser, Digikey. This is a very
as
it is used in a lot of "EXIT" signs so they are lighted when
out. I don't see how the 12V 7AH will fit as they are too
you could use a 12V 5AH (PS1250) as it is the same size as 2
but the terminals are in the wrong place so you will have to
the aluminum plate that holds them in the 732A battery pack.
be
careful if you use the 12v 5AH as you will have 4 extra
leads to deal with and connect correctly. I would stick with
New batteries will last around 12 to 14 hours before the
out when AC power is not applied. So shipping to Cal Lab
if it is a distance away, or you have to use a shipper like
and
you ship the night before and then use their "Morning
Lab is expecting your 732A. Same on the way back to you. Of
could always strap another battery on the 732A and hook it
power" plug to last longer. I have seen it done. The issue
Cal Lab to charge the extra battery before they ship the 732A
When you remove and work on the battery pack always have
plugged in. The "CAL" led will stay on because the 18.6 v
is working.
The "CAL" light is to indicate that power has not been
Reference Amp or other associated circuits. When the raw
voltage drops below about 21 volts the "CAL" light will go
voltage the heater circuits will not work correctly and the
regulated supply will not regulate. The requirement is that
Amp be kept "alive" at all times to maintain the output
measured at the time of the most recent Calibration or
the semiconductor junctions are unbiased and cool off when
and then power is restored the result will be a different 10
before the power failure. My experience is that after all
that
these units have been powered up, this won't happen and when
and then restored, even months later, the 732A will come
exactly the same 10 volts as when they lost power, usually
after 24 hours of "warm up".
What type of hookup leads are you using when measuring
output? What is the PLC set to? I always use 100 PLC to
you don't have "low thermal" connection leads you can
for a minute or more after plugging in the leads due to the
generated because of the difference in temperature between
on the 732A and the banana plugs of the leads. I have found
plugging in the lead will generate a thermal difference
difference of temps and some heating due to the physical act
inserting the plug because of friction between the jack and
at any rate). You have to allow at least a minute or more
able
to make a measurement after plugging in the leads. I just
variation of the 1 volt output of my 732A and using my 3458A
total difference of 0.159 uV over 40 measurements using 100
volt range of the 3458A. Using the MATH function and all of
can collect. That was after waiting for several minutes
the leads.
I hope all of this helps.
Bill
----- Original Message -----
From: "Randy Evans" randyevans2688@gmail.com
To: "Discussion of precise voltage measurement" <
Sent: Friday, August 22, 2014 9:03 PM
Subject: Re: [volt-nuts] 732A and Prologix received
Todd,
Thanks for the info. I have several Panasonic 12V 7 AH
keep topped off and they have very low current draw (~2 to
VDC) when charged and at their float voltage, so I am
in good condition. I will look at getting those in the
ascertain the condition of the 732.
So now I have a what appears to be a functioning 3458A and
slightly disagree. I am like the man with two watches that
time - which is correct? For the moment, i am only
stability. The need for absolute accuracy will come later.
Randy
On Fri, Aug 22, 2014 at 8:06 PM, Todd Micallef <
Randy,
You have two possible choices. It can be configured with
batteries or 2 x 12v 7Ah batteries. Hopefully the
modified the battery pack already. A couple of mine
to remove enough of the aluminum cover that fits over the
batteries. The original cover will short out to the
of the battery configuration if this is not done.
You can find larger capacity batteries that will give you
battery life. I lost a couple sets of mail-order
extended outages. I would recommend going with locally
instead of the cheaper mail order. My local Batteries
have some warranty if I remember correctly. Moving
2 12v batteries and pre-charge them on a battery charger
before putting them in the 732A. I think the cheap
discharge equally, and would not recover when power was
Inspect the back plane for damaged traces and look at the
a few that looked questionable. So far, I have replaced
the pre-regulator and regulator boards. My feeling is
online, they should run as long as possible between
The battery charger circuit may need adjusting. I tweaked
seemed to work fine.
Todd
On Fri, Aug 22, 2014 at 10:42 PM, Randy Evans <
I received my Fluke 732A today. Just powered it up
batteries. Any suggestions for sources (I haven't
I want to make sure it works before doing that). Also
ProLogix USB-GPIB adapter. I plan on using Mark Sims'
program to get the CAL data from my 3458A. Should be a
and follow the instructions there.
and follow the instructions there.
and follow the instructions there.
and follow the instructions there.
and follow the instructions there.
hi randy,
the specified drift of the 3458a over your 38.1 to 40.3 (about 1k) is 1ppm +/- allone in the 10v range. thats 10uv. in other ranges its worse.
unless your 732a is very bad (very unlikely), you measure mostly the 3458a temp. drift. 1000nplc and 100 readings average do not make sense in that context. if your goal is to be at 0.01ppm additional gain error by using the nplc1000, you need to be sure your temp related drift is even below that. 0.01ppm of temp drift equates 20mk temp stability! you see that all this does not make much sense.
adrian
> Gesendet: Mittwoch, 27. August 2014 um 15:37 Uhr
> Von: "Randy Evans" <randyevans2688@gmail.com>
> An: "Discussion of precise voltage measurement" <volt-nuts@febo.com>
> Betreff: Re: [volt-nuts] 732A and Prologix received
>
> The HP3458A and the Fluke 732A are on continuously and I do an ACAL at
> least every few hours, or when the room temperature changes by more than 1
> degree C. The total range of measurements is 10uV so the drift is +/-5uV,
> or 0.5 ppm. The room temperature is not particularly stable and varies
> over a 3C range. The internal temp of the 3458 varies from 38.1 to 40.3
> degrees C over the set of measurements. The 732A thermistor resistance
> measures from 3.6677 Kohms to 3.6686 Kohms. I am using copper wires
> between the 3458A and the 752A to minimize thermals. At the moment I have
> no way to tell which unit is drifting the most.
>
> Randy
>
>
> On Wed, Aug 27, 2014 at 6:41 AM, <acbern@gmx.de> wrote:
>
> > well, what you do is to measure the stability of the 3458a. 1ppm drift
> > though sounds much as overall short term average variation if your
> > temperature is stable and your 3458a is always on. probably the temp is not
> > stable, and that is what you see, amongst potentially some other smaller
> > drifts like emf. before every cycle you should do an acal dcv, if you still
> > see 10uv +/- drifts that then seems too much. (one thing I need to add is
> > that one of my 3458a, not yet modified to have lower reference temperature,
> > has drifts when switched on and off. that is not so much the case with
> > modified reference. but my assumption re the above is that your meter is
> > always on, as I said)
> > 732a references et al do have small short term drifts, you can determine
> > them with a josephson element (these guys told me), but the 732a is
> > certainly very stable short term compared to a 3458a. my 732a e.g. has a
> > drift of 0.2ppm per year.
> >
> >
> > > Gesendet: Mittwoch, 27. August 2014 um 14:36 Uhr
> > > Von: "Randy Evans" <randyevans2688@gmail.com>
> > > An: "Discussion of precise voltage measurement" <volt-nuts@febo.com>
> > > Betreff: Re: [volt-nuts] 732A and Prologix received
> > >
> > > I forgot to mention that I reduced the number of measurements to 100 per
> > > set since I wasn't seeing much difference in the variance between 100 and
> > > 1000 measurements and the 1000 measurement per set takes too long.
> > >
> > > Randy
> > >
> > >
> > > On Wed, Aug 27, 2014 at 5:13 AM, Randy Evans <randyevans2688@gmail.com>
> > > wrote:
> > >
> > > > I am doing multiple 100 measurements simply to characterize the
> > stability
> > > > of the 3458A and 732A units I just bought. After about 10 measurement
> > sets
> > > > over 2 days I am seeing a variance of about .5 uV for the 10V output,
> > or
> > > > 0.05 ppm. However, the mean varies over a range of 10 uV, or 1 ppm.
> > Does
> > > > that sound reasonable/
> > > >
> > > > Randy
> > > >
> > > >
> > > > On Tue, Aug 26, 2014 at 5:41 PM, <acbern@gmx.de> wrote:
> > > >
> > > >> hi randy,
> > > >>
> > > >> just for curiosity, why doing 100 measurements at nplc 1000. is this
> > to
> > > >> sample a changing value?
> > > >> when i am doing 10 measurements from a stable signal at nplc 100 (only
> > > >> there many subsequent measuremnts with statistics make sense) I am
> > already
> > > >> getting a stanard deviation below 0.1ppm.
> > > >> in a 30 minute test cycle, i would also be concerned about drifts
> > (acal)
> > > >> unless the amb. temperature is really very stable (half a degree
> > already
> > > >> adds about 0.25ppm at 10v)
> > > >>
> > > >> thanks
> > > >>
> > > >>
> > > >>
> > > >>
> > > >> > Gesendet: Dienstag, 26. August 2014 um 04:23 Uhr
> > > >> > Von: "Randy Evans" <randyevans2688@gmail.com>
> > > >> > An: "Discussion of precise voltage measurement" <volt-nuts@febo.com
> > >
> > > >> > Betreff: Re: [volt-nuts] 732A and Prologix received
> > > >> >
> > > >> > Is there any way to tell when the function key routine is
> > complete? In
> > > >> the
> > > >> > case of taking multiple readings using the DEFKEY and MATH
> > function, I
> > > >> > don't see any indication when the routine is complete. In one
> > > >> particular
> > > >> > case, I am taking a 100 readings with NLPC set for 1000 so its a
> > long
> > > >> while
> > > >> > before it's complete, but i have to guess when it's done.
> > > >> >
> > > >> > Thanks,
> > > >> >
> > > >> > Randy
> > > >> >
> > > >> >
> > > >> > On Sun, Aug 24, 2014 at 6:04 PM, Randy Evans <
> > randyevans2688@gmail.com>
> > > >> > wrote:
> > > >> >
> > > >> > > Bill,
> > > >> > >
> > > >> > > I am trying to figure out the MATH function without much
> > success. I
> > > >> input
> > > >> > > the sequence you said (I looked up the instructions to understand
> > > >> what you
> > > >> > > did - seems logical), BLUE DEFKEY BLUE F1 MATH 14;NRDGS 40;TRIG
> > > >> 4;TRIG; and
> > > >> > > it shows up on the display when I input BLUE F1. I hit ENTER and
> > it
> > > >> takes
> > > >> > > the 40 measurements and the MATH symbol shows on the display
> > during
> > > >> the
> > > >> > > measurements. After the SMPL symbol no longer blinks I hit MATH 2
> > > >> and I
> > > >> > > get a MATH ERR symbol on the display. I tried it a couple of
> > times
> > > >> and the
> > > >> > > same result so I am doing something wrong. Is there a better
> > source
> > > >> for
> > > >> > > explaining how to do front panel masurements than the User Guide,
> > > >> which
> > > >> > > seems oriented at programming automatic rather than manual
> > > >> measurements.
> > > >> > >
> > > >> > > Randy
> > > >> > >
> > > >> > >
> > > >> > >
> > > >> > > On Sun, Aug 24, 2014 at 4:46 PM, Bill Gold <wpgold3637@att.net>
> > > >> wrote:
> > > >> > >
> > > >> > >> Randy:
> > > >> > >>
> > > >> > >> The MATH function is accessible from the keypad. I don't
> > have
> > > >> an IEEE
> > > >> > >> interface right now that works. You can also program the numeric
> > > >> keypad
> > > >> > >> keys to have preprogrammed functions. DEFKEY
> > > >> > >>
> > > >> > >> I have made my own "low thermal" measurement leads from
> > Pomona
> > > >> #4892
> > > >> > >> banana plugs and Belden #9272 wire. Why 9272, because it was
> > handy
> > > >> at the
> > > >> > >> time. It is tin plated copper, shielded twisted pair 20 ga. I
> > have
> > > >> plans
> > > >> > >> to do custom cables with 16 ga. bare copper wire that I will
> > twist
> > > >> and
> > > >> > >> then
> > > >> > >> put a braided shield over it. I simply cannot find what I want
> > so I
> > > >> will
> > > >> > >> build my own cable. I have done something like this before and
> > it
> > > >> worked
> > > >> > >> fine. When I get a "round toit".
> > > >> > >>
> > > >> > >> I have 6 ea. Pomona 1756-48 spade lug low thermal leads that
> > I
> > > >> have
> > > >> > >> used
> > > >> > >> in the past to verify my homemade "low thermal" leads as
> > described
> > > >> above.
> > > >> > >> Frankly I cannot see any difference between using the 1756 cables
> > > >> and my
> > > >> > >> homemade cables once I give them a few minutes for the thermals
> > to go
> > > >> > >> away.
> > > >> > >> As far as I can tell and measure the differences, if any, are
> > below
> > > >> 0.1
> > > >> > >> ppm
> > > >> > >> at 10 volts.
> > > >> > >>
> > > >> > >> Since the 10 volt, 1.0 volt and 1.018 volt outputs on the
> > 732A
> > > >> are all
> > > >> > >> adjustable you may be seeing a misadjusted 1 volt from the
> > 732A. As
> > > >> far
> > > >> > >> as
> > > >> > >> the instability of the readings it is hard to determine which is
> > > >> causing
> > > >> > >> the
> > > >> > >> problem. I have programed (DEFKEY) a numeric keypad key #1 with
> > the
> > > >> > >> following code. "MATH 14;NRDGS 40;TRIG 4;TRIG ;" So what this
> > > >> does is
> > > >> > >> set
> > > >> > >> the MATH to "Statistics" (store high reading/low reading/ and
> > mean
> > > >> of the
> > > >> > >> readings) in the registers, the number of readings to "40", the
> > > >> trigger to
> > > >> > >> "hold" (which keeps the meter from triggering until I press
> > "ENTER"
> > > >> and
> > > >> > >> then
> > > >> > >> trigger the sequence of 40 readings when I push the "ENTER"
> > button.
> > > >> You
> > > >> > >> can
> > > >> > >> do all of this manually from the keypads but since I use this
> > > >> sequence a
> > > >> > >> lot
> > > >> > >> I have preprogrammed it. This is after I set digits to "8" and
> > PLC
> > > >> to
> > > >> > >> 100.
> > > >> > >> Once those 40 readings are finished then you can access the
> > various
> > > >> MATH
> > > >> > >> statistic registers, using the menu, by entering "MATH" and then
> > a 2
> > > >> for
> > > >> > >> low, a 4 for mean, and 13 for high. Of course you could do all
> > of
> > > >> this
> > > >> > >> through the IEEE also. The 3458A has a very rich set of
> > measurement
> > > >> > >> commands. I am still learning all of them. It depends upon
> > what I
> > > >> am
> > > >> > >> trying to accomplish.
> > > >> > >>
> > > >> > >> Since the 1.018 and 1.0 volt outputs are passive and derived
> > from
> > > >> > >> resistive dividers from the 10 volt, I don't see how they could
> > > >> contribute
> > > >> > >> to the varying readings you are measuring. I think I would put a
> > > >> short on
> > > >> > >> the input of the 3458A and manually set the range to 1 volt and
> > then
> > > >> > >> observe
> > > >> > >> the variations that way without the 732A involved. When I do
> > this I
> > > >> see a
> > > >> > >> variation from low reading to high reading of 0.125 uVolts and
> > then
> > > >> > >> another
> > > >> > >> 40 I get 0.155 uVolts. This is without the GUARD connected to
> > the
> > > >> low
> > > >> > >> side
> > > >> > >> of the measurment terminals, GUARD connected doesn't seem to
> > affect
> > > >> the
> > > >> > >> readings. So that is the base noise of the 3458A without the
> > 732A,
> > > >> > >> somewhere below .2uVolts. When hooked up to the 732A 1.0 volt
> > > >> output I
> > > >> > >> got
> > > >> > >> a variation of 0.159 uVolts using the same 40 reading method
> > above.
> > > >> I
> > > >> > >> would
> > > >> > >> use this to determine where your problem might exist. Just
> > having
> > > >> the
> > > >> > >> meter
> > > >> > >> input shorted will point you in the right direction. Meter,
> > cables
> > > >> or
> > > >> > >> 732A.
> > > >> > >>
> > > >> > >> Sorry for the long dissertation. Friends get mad at me for
> > > >> being so
> > > >> > >> detailed sometimes.
> > > >> > >>
> > > >> > >> Bill
> > > >> > >>
> > > >> > >> ----- Original Message -----
> > > >> > >> From: "Randy Evans" <randyevans2688@gmail.com>
> > > >> > >> To: "Discussion of precise voltage measurement" <
> > volt-nuts@febo.com>
> > > >> > >> Sent: Sunday, August 24, 2014 7:22 AM
> > > >> > >> Subject: Re: [volt-nuts] 732A and Prologix received
> > > >> > >>
> > > >> > >>
> > > >> > >> > Bill,
> > > >> > >> >
> > > >> > >> > I have convinced myself that the problem I an seeing is due to
> > > >> thermals.
> > > >> > >> > If I move the cables (with gold-plated banana plugs) using a
> > small
> > > >> > >> towel
> > > >> > >> > rather than letting my hand touch the plugs, it is much more
> > > >> stable.
> > > >> > >> If I
> > > >> > >> > then hold the banana plug with my hand after the reading has
> > > >> stabilized,
> > > >> > >> > the reading drifts rapidly upward. I am trying to check the
> > > >> stability
> > > >> > >> of
> > > >> > >> > the reading but I haven't figured out the MATH function yet. I
> > > >> assume
> > > >> > >> this
> > > >> > >> > is a programmed function using GPIB only?
> > > >> > >> >
> > > >> > >> > The stability I am seeing by manually recording readings (using
> > > >> NLPC of
> > > >> > >> 100
> > > >> > >> > and 1000) is much greater than what you are measuring on your
> > > >> system.
> > > >> > >> Not
> > > >> > >> > sure how to ascertain if it's the 3458A or the 732. The value
> > of
> > > >> the
> > > >> > >> > readings are very different between the two - the 3458 reads
> > about
> > > >> 50 uV
> > > >> > >> > high on the 10 V output and about 12 uV low on the 1V output.
> > > >> Rather
> > > >> > >> large
> > > >> > >> > differences (this is after an ACAL). I need to find some
> > better
> > > >> cables
> > > >> > >> to
> > > >> > >> > make sure the errors are not due to thermals again.
> > > >> > >> >
> > > >> > >> > Randy
> > > >> > >> >
> > > >> > >> >
> > > >> > >> > On Sat, Aug 23, 2014 at 10:21 AM, Bill Gold <
> > wpgold3637@att.net>
> > > >> wrote:
> > > >> > >> >
> > > >> > >> > > Randy:
> > > >> > >> > >
> > > >> > >> > > I get 6 volt 4 amp/hr (or 4.5 amp/hr) batteries and they
> > > >> will fit
> > > >> > >> > > perfect. Power Sonic PS-640, Genesis NP4-6, Panasonic
> > > >> LC-R064R5C and
> > > >> > >> > > others
> > > >> > >> > > that are in this size and package. Order from one of the
> > usual
> > > >> > >> electronics
> > > >> > >> > > distributors like Allied, Mouser, Digikey. This is a very
> > common
> > > >> > >> battery
> > > >> > >> > > as
> > > >> > >> > > it is used in a lot of "EXIT" signs so they are lighted when
> > the
> > > >> power
> > > >> > >> goes
> > > >> > >> > > out. I don't see how the 12V 7AH will fit as they are too
> > > >> large. I
> > > >> > >> guess
> > > >> > >> > > you could use a 12V 5AH (PS1250) as it is the same size as 2
> > x 6
> > > >> volt
> > > >> > >> 4
> > > >> > >> AH
> > > >> > >> > > but the terminals are in the wrong place so you will have to
> > > >> "nibble"
> > > >> > >> out
> > > >> > >> > > the aluminum plate that holds them in the 732A battery pack.
> > > >> You have
> > > >> > >> to
> > > >> > >> > > be
> > > >> > >> > > careful if you use the 12v 5AH as you will have 4 extra
> > battery
> > > >> > >> connection
> > > >> > >> > > leads to deal with and connect correctly. I would stick with
> > > >> the 6V
> > > >> > >> 4AH.
> > > >> > >> > > New batteries will last around 12 to 14 hours before the
> > "CAL"
> > > >> light
> > > >> > >> goes
> > > >> > >> > > out when AC power is not applied. So shipping to Cal Lab
> > can be
> > > >> a
> > > >> > >> problem
> > > >> > >> > > if it is a distance away, or you have to use a shipper like
> > UPS
> > > >> or
> > > >> > >> FEDEX
> > > >> > >> > > and
> > > >> > >> > > you ship the night before and then use their "Morning
> > delivery"
> > > >> and
> > > >> > >> the
> > > >> > >> Cal
> > > >> > >> > > Lab is expecting your 732A. Same on the way back to you. Of
> > > >> course
> > > >> > >> you
> > > >> > >> > > could always strap another battery on the 732A and hook it
> > up to
> > > >> the
> > > >> > >> "ext
> > > >> > >> > > power" plug to last longer. I have seen it done. The issue
> > is
> > > >> to get
> > > >> > >> the
> > > >> > >> > > Cal Lab to charge the extra battery before they ship the 732A
> > > >> back to
> > > >> > >> you.
> > > >> > >> > >
> > > >> > >> > > When you remove and work on the battery pack always have
> > the
> > > >> AC
> > > >> > >> power
> > > >> > >> > > plugged in. The "CAL" led will stay on because the 18.6 v
> > > >> regulated
> > > >> > >> supply
> > > >> > >> > > is working.
> > > >> > >> > >
> > > >> > >> > > The "CAL" light is to indicate that power has not been
> > lost
> > > >> to the
> > > >> > >> > > Reference Amp or other associated circuits. When the raw
> > supply
> > > >> > >> (battery)
> > > >> > >> > > voltage drops below about 21 volts the "CAL" light will go
> > out.
> > > >> Below
> > > >> > >> that
> > > >> > >> > > voltage the heater circuits will not work correctly and the
> > 18.6
> > > >> volt
> > > >> > >> > > regulated supply will not regulate. The requirement is that
> > the
> > > >> > >> Reference
> > > >> > >> > > Amp be kept "alive" at all times to maintain the output
> > voltage
> > > >> that
> > > >> > >> was
> > > >> > >> > > measured at the time of the most recent Calibration or
> > > >> Certification.
> > > >> > >> When
> > > >> > >> > > the semiconductor junctions are unbiased and cool off when
> > power
> > > >> is
> > > >> > >> lost,
> > > >> > >> > > and then power is restored the result will be a different 10
> > > >> volts
> > > >> > >> than
> > > >> > >> > > before the power failure. My experience is that after all
> > of the
> > > >> > >> years
> > > >> > >> > > that
> > > >> > >> > > these units have been powered up, this won't happen and when
> > > >> power is
> > > >> > >> lost
> > > >> > >> > > and then restored, even months later, the 732A will come
> > back to
> > > >> > >> almost
> > > >> > >> > > exactly the same 10 volts as when they lost power, usually
> > with
> > > >> in 0.2
> > > >> > >> PPM
> > > >> > >> > > after 24 hours of "warm up".
> > > >> > >> > >
> > > >> > >> > > What type of hookup leads are you using when measuring
> > the 1
> > > >> volt
> > > >> > >> > > output? What is the PLC set to? I always use 100 PLC to
> > measure
> > > >> > >> this.
> > > >> > >> If
> > > >> > >> > > you don't have "low thermal" connection leads you can
> > experience
> > > >> uV
> > > >> > >> changes
> > > >> > >> > > for a minute or more after plugging in the leads due to the
> > > >> "thermals"
> > > >> > >> > > generated because of the difference in temperature between
> > the
> > > >> banana
> > > >> > >> jacks
> > > >> > >> > > on the 732A and the banana plugs of the leads. I have found
> > > >> that even
> > > >> > >> just
> > > >> > >> > > plugging in the lead will generate a thermal difference
> > because
> > > >> of
> > > >> > >> > > difference of temps and some heating due to the physical act
> > of
> > > >> just
> > > >> > >> > > inserting the plug because of friction between the jack and
> > plug
> > > >> (my
> > > >> > >> theory
> > > >> > >> > > at any rate). You have to allow at least a minute or more
> > before
> > > >> > >> being
> > > >> > >> > > able
> > > >> > >> > > to make a measurement after plugging in the leads. I just
> > > >> measured
> > > >> > >> the
> > > >> > >> > > variation of the 1 volt output of my 732A and using my 3458A
> > and
> > > >> I
> > > >> > >> got a
> > > >> > >> > > total difference of 0.159 uV over 40 measurements using 100
> > PLC
> > > >> on
> > > >> > >> the
> > > >> > >> 1
> > > >> > >> > > volt range of the 3458A. Using the MATH function and all of
> > the
> > > >> data
> > > >> > >> you
> > > >> > >> > > can collect. That was after waiting for several minutes
> > after
> > > >> > >> plugging
> > > >> > >> in
> > > >> > >> > > the leads.
> > > >> > >> > >
> > > >> > >> > > I hope all of this helps.
> > > >> > >> > >
> > > >> > >> > > Bill
> > > >> > >> > >
> > > >> > >> > >
> > > >> > >> > >
> > > >> > >> > > ----- Original Message -----
> > > >> > >> > > From: "Randy Evans" <randyevans2688@gmail.com>
> > > >> > >> > > To: "Discussion of precise voltage measurement" <
> > > >> volt-nuts@febo.com>
> > > >> > >> > > Sent: Friday, August 22, 2014 9:03 PM
> > > >> > >> > > Subject: Re: [volt-nuts] 732A and Prologix received
> > > >> > >> > >
> > > >> > >> > >
> > > >> > >> > > > Todd,
> > > >> > >> > > >
> > > >> > >> > > > Thanks for the info. I have several Panasonic 12V 7 AH
> > > >> batteries
> > > >> > >> that
> > > >> > >> I
> > > >> > >> > > > keep topped off and they have very low current draw (~2 to
> > 3
> > > >> mA at
> > > >> > >> 13.5
> > > >> > >> > > > VDC) when charged and at their float voltage, so I am
> > pretty
> > > >> sure
> > > >> > >> they
> > > >> > >> > > are
> > > >> > >> > > > in good condition. I will look at getting those in the
> > units
> > > >> after
> > > >> > >> I
> > > >> > >> > > > ascertain the condition of the 732.
> > > >> > >> > > >
> > > >> > >> > > > So now I have a what appears to be a functioning 3458A and
> > a
> > > >> 732A
> > > >> > >> but
> > > >> > >> > > they
> > > >> > >> > > > slightly disagree. I am like the man with two watches that
> > > >> disagree
> > > >> > >> on
> > > >> > >> > > the
> > > >> > >> > > > time - which is correct? For the moment, i am only
> > concerned
> > > >> with
> > > >> > >> > > > stability. The need for absolute accuracy will come later.
> > > >> > >> > > >
> > > >> > >> > > > Randy
> > > >> > >> > > >
> > > >> > >> > > >
> > > >> > >> > > > On Fri, Aug 22, 2014 at 8:06 PM, Todd Micallef <
> > > >> tmicallef@gmail.com
> > > >> > >> >
> > > >> > >> > > wrote:
> > > >> > >> > > >
> > > >> > >> > > > > Randy,
> > > >> > >> > > > >
> > > >> > >> > > > > You have two possible choices. It can be configured with
> > 4 x
> > > >> 6v
> > > >> > >> 4Ah
> > > >> > >> > > > > batteries or 2 x 12v 7Ah batteries. Hopefully the
> > previous
> > > >> owner
> > > >> > >> has
> > > >> > >> > > > > modified the battery pack already. A couple of mine
> > needed a
> > > >> > >> nibbler
> > > >> > >> > > tool
> > > >> > >> > > > > to remove enough of the aluminum cover that fits over the
> > > >> tops of
> > > >> > >> the
> > > >> > >> > > > > batteries. The original cover will short out to the
> > battery
> > > >> tabs
> > > >> > >> > > regardless
> > > >> > >> > > > > of the battery configuration if this is not done.
> > > >> > >> > > > >
> > > >> > >> > > > > You can find larger capacity batteries that will give you
> > > >> slightly
> > > >> > >> more
> > > >> > >> > > > > battery life. I lost a couple sets of mail-order
> > batteries
> > > >> after a
> > > >> > >> few
> > > >> > >> > > > > extended outages. I would recommend going with locally
> > bought
> > > >> > >> batteries
> > > >> > >> > > > > instead of the cheaper mail order. My local Batteries
> > Plus
> > > >> will
> > > >> > >> > > typically
> > > >> > >> > > > > have some warranty if I remember correctly. Moving
> > forward I
> > > >> will
> > > >> > >> only
> > > >> > >> > > use
> > > >> > >> > > > > 2 12v batteries and pre-charge them on a battery charger
> > to
> > > >> > >> equalize
> > > >> > >> > > them
> > > >> > >> > > > > before putting them in the 732A. I think the cheap
> > batteries
> > > >> did
> > > >> > >> not
> > > >> > >> > > > > discharge equally, and would not recover when power was
> > > >> applied.
> > > >> > >> > > > >
> > > >> > >> > > > > Inspect the back plane for damaged traces and look at the
> > > >> > >> capacitors. I
> > > >> > >> > > had
> > > >> > >> > > > > a few that looked questionable. So far, I have replaced
> > all
> > > >> the
> > > >> > >> big
> > > >> > >> > > caps
> > > >> > >> > > on
> > > >> > >> > > > > the pre-regulator and regulator boards. My feeling is
> > that
> > > >> once
> > > >> > >> these
> > > >> > >> > > go
> > > >> > >> > > > > online, they should run as long as possible between
> > repairs.
> > > >> > >> > > > >
> > > >> > >> > > > > The battery charger circuit may need adjusting. I tweaked
> > > >> mine and
> > > >> > >> it
> > > >> > >> > > > > seemed to work fine.
> > > >> > >> > > > >
> > > >> > >> > > > > Todd
> > > >> > >> > > > >
> > > >> > >> > > > >
> > > >> > >> > > > > On Fri, Aug 22, 2014 at 10:42 PM, Randy Evans <
> > > >> > >> > > randyevans2688@gmail.com>
> > > >> > >> > > > > wrote:
> > > >> > >> > > > >
> > > >> > >> > > > > > I received my Fluke 732A today. Just powered it up
> > but it
> > > >> needs
> > > >> > >> new
> > > >> > >> > > > > > batteries. Any suggestions for sources (I haven't
> > opened
> > > >> up the
> > > >> > >> unit
> > > >> > >> > > > > yet -
> > > >> > >> > > > > > I want to make sure it works before doing that). Also
> > > >> received
> > > >> > >> the
> > > >> > >> > > > > > ProLogix USB-GPIB adapter. I plan on using Mark Sims'
> > CAL
> > > >> ran
> > > >> > >> data
> > > >> > >> > > > > dumper
> > > >> > >> > > > > > program to get the CAL data from my 3458A. Should be a
> > > >> busy
> > > >> > >> weekend.
> > > >> > >> > > > > >
> > > >> > >> > > > > > Randy
> > > >> > >> > > > > > _______________________________________________
> > > >> > >> > > > > > volt-nuts mailing list -- volt-nuts@febo.com
> > > >> > >> > > > > > To unsubscribe, go to
> > > >> > >> > > > > >
> > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> > > >> > >> > > > > > and follow the instructions there.
> > > >> > >> > > > > >
> > > >> > >> > > > > _______________________________________________
> > > >> > >> > > > > volt-nuts mailing list -- volt-nuts@febo.com
> > > >> > >> > > > > To unsubscribe, go to
> > > >> > >> > > > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> > > >> > >> > > > > and follow the instructions there.
> > > >> > >> > > > >
> > > >> > >> > > > _______________________________________________
> > > >> > >> > > > volt-nuts mailing list -- volt-nuts@febo.com
> > > >> > >> > > > To unsubscribe, go to
> > > >> > >> > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> > > >> > >> > > > and follow the instructions there.
> > > >> > >> > >
> > > >> > >> > > _______________________________________________
> > > >> > >> > > volt-nuts mailing list -- volt-nuts@febo.com
> > > >> > >> > > To unsubscribe, go to
> > > >> > >> > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> > > >> > >> > > and follow the instructions there.
> > > >> > >> > >
> > > >> > >> > _______________________________________________
> > > >> > >> > volt-nuts mailing list -- volt-nuts@febo.com
> > > >> > >> > To unsubscribe, go to
> > > >> > >> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> > > >> > >> > and follow the instructions there.
> > > >> > >>
> > > >> > >> _______________________________________________
> > > >> > >> volt-nuts mailing list -- volt-nuts@febo.com
> > > >> > >> To unsubscribe, go to
> > > >> > >> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> > > >> > >> and follow the instructions there.
> > > >> > >>
> > > >> > >
> > > >> > >
> > > >> > _______________________________________________
> > > >> > volt-nuts mailing list -- volt-nuts@febo.com
> > > >> > To unsubscribe, go to
> > > >> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> > > >> > and follow the instructions there.
> > > >> _______________________________________________
> > > >> volt-nuts mailing list -- volt-nuts@febo.com
> > > >> To unsubscribe, go to
> > > >> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> > > >> and follow the instructions there.
> > > >>
> > > >
> > > >
> > > _______________________________________________
> > > volt-nuts mailing list -- volt-nuts@febo.com
> > > To unsubscribe, go to
> > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> > > and follow the instructions there.
> > _______________________________________________
> > volt-nuts mailing list -- volt-nuts@febo.com
> > To unsubscribe, go to
> > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> > and follow the instructions there.
> >
> _______________________________________________
> volt-nuts mailing list -- volt-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> and follow the instructions there.
MK
M K
Wed, Aug 27, 2014 7:45 PM
On 26/08/2014 16:05, Mike S wrote:
After some more research, I think I've answered some of my own
questions -
Tellurium copper is used for binding posts, not because it has any
special thermal or EMF mojo, but because it machines much better than
pure copper. And, I suppose, because it sounds like it's extra special.
The Seebeck coefficients (uV/C, relative to Cu) of some relevant
materials:
Cu 0.0
Ag .2
Au .5
Yellow brass 1.5
Phosphor bronze 2.0
63/37 solder 3.0
Sn 3.1
Stainless steel 3.1
Beryllium copper 5.0
Fe -12.3
Ni 22.3
Te -49.25
Based on the extreme Seebeck coefficient of pure tellurium vs. copper,
I'd expect that there might be some coefficient between Cu and CuTe
(0.5% Te), but I could find no reference. The relatively large number
for CuBe is interesting, since that's a common material for banana
plug springs, where one might expect the greatest temperature
differential to occur in such a connection (between the thermal masses
of the binding post/jack and the bulk of the banana plug). Heat has to
flow a considerable distance through the springs, very much more than
when it flows through a surface plating.
The Pomona (Fluke) EM5295-48-0# uses CuBe (gold plated) for the spring
contacts. It seems there might be an improvement to be had by using
the older style pin plugs, where a solid pin was partially sliced into
4 sections which were then spread apart a bit to create tension. That
could eliminate relatively large thermocouples at a thermal gradient,
and might also be expected to have less thermal resistance, allowing
the connection to settle quicker.
But maybe not - I'm still not clear on how plated conductors behave in
this situation. For a high impedance voltage measurement where almost
no current flows, the gold plating may carry the signal, so there is
no real thermocouple (or more correctly, it's entirely contained
within the connector). But if that's the case, why fool around with
special copper connectors when common brass ones would be
easier/cheaper? For current or resistance, the signal would also flow
through the base metal, so does this have an effect (especially for
tinned copper test leads, where there may be a larger temperature
difference between the ends???
Nickle is avoided as a contact material largely because it is subject
to fretting corrosion. Tests done by AMP
(http://www.te.com/documentation/whitepapers/pdf/p154-74.pdf) show
that a Ni to Ni contact can increase from 8 mOhm to 5 Ohms (sic!) in a
short time due to this, while Ag and Au plated contacts exhibit
negligible changes.
Cu (with Be for better machining) seems to be used as the base
material for jacks/plugs to get thermal EMF cancellation to the wiring
on both sides (i.e. use copper everywhere except where there is a
minimal thermal gradient, like platings).
Beryllium copper is a springy material, Tellurium is the material added
to aid machining without adding too much seebeck coefficient.
I remember someone on this list a long time ago saying that NPL used van
damme star quad cable and bought bulk quantities of spade lugs that they
strip all the coating off before crimping and clean before each use.
On 26/08/2014 16:05, Mike S wrote:
> After some more research, I think I've answered some of my own
> questions -
>
> Tellurium copper is used for binding posts, not because it has any
> special thermal or EMF mojo, but because it machines much better than
> pure copper. And, I suppose, because it sounds like it's extra special.
>
> The Seebeck coefficients (uV/C, relative to Cu) of some relevant
> materials:
> Cu 0.0
> Ag .2
> Au .5
> Yellow brass 1.5
> Phosphor bronze 2.0
> 63/37 solder 3.0
> Sn 3.1
> Stainless steel 3.1
> Beryllium copper 5.0
> Fe -12.3
> Ni 22.3
> Te -49.25
>
> Based on the extreme Seebeck coefficient of pure tellurium vs. copper,
> I'd expect that there might be some coefficient between Cu and CuTe
> (0.5% Te), but I could find no reference. The relatively large number
> for CuBe is interesting, since that's a common material for banana
> plug springs, where one might expect the greatest temperature
> differential to occur in such a connection (between the thermal masses
> of the binding post/jack and the bulk of the banana plug). Heat has to
> flow a considerable distance through the springs, very much more than
> when it flows through a surface plating.
>
> The Pomona (Fluke) EM5295-48-0# uses CuBe (gold plated) for the spring
> contacts. It seems there might be an improvement to be had by using
> the older style pin plugs, where a solid pin was partially sliced into
> 4 sections which were then spread apart a bit to create tension. That
> could eliminate relatively large thermocouples at a thermal gradient,
> and might also be expected to have less thermal resistance, allowing
> the connection to settle quicker.
>
> But maybe not - I'm still not clear on how plated conductors behave in
> this situation. For a high impedance voltage measurement where almost
> no current flows, the gold plating may carry the signal, so there is
> no real thermocouple (or more correctly, it's entirely contained
> within the connector). But if that's the case, why fool around with
> special copper connectors when common brass ones would be
> easier/cheaper? For current or resistance, the signal would also flow
> through the base metal, so does this have an effect (especially for
> tinned copper test leads, where there may be a larger temperature
> difference between the ends???
>
> Nickle is avoided as a contact material largely because it is subject
> to fretting corrosion. Tests done by AMP
> (http://www.te.com/documentation/whitepapers/pdf/p154-74.pdf) show
> that a Ni to Ni contact can increase from 8 mOhm to 5 Ohms (sic!) in a
> short time due to this, while Ag and Au plated contacts exhibit
> negligible changes.
>
> Cu (with Be for better machining) seems to be used as the base
> material for jacks/plugs to get thermal EMF cancellation to the wiring
> on both sides (i.e. use copper everywhere except where there is a
> minimal thermal gradient, like platings).
>
Beryllium copper is a springy material, Tellurium is the material added
to aid machining without adding too much seebeck coefficient.
I remember someone on this list a long time ago saying that NPL used van
damme star quad cable and bought bulk quantities of spade lugs that they
strip all the coating off before crimping and clean before each use.
SK
Stan Katz
Wed, Aug 27, 2014 9:50 PM
As a non-scholar in metrology, I tend to want to simplify the results of an
academic debate to make the results of the debate useful to me. One thing
is clear from my web search, copper alloyed with Tellurium, or Beryllium,
still oxidizes, only at a slower rate. It appears that a big disadvantage
of Beryllium oxide is its very hard, a useful industrial characteristic.
Not a nice property in the metrology lab.
Here goes:
For the purists with lab grade metallurgical abrasives, polishing
equipment, and oxide removal chemistry, only, copper, whether alloyed with
Beryllium or Tellurium is all they want to see in their lead terminations,
and they will try to procure only instruments with copper/copper alloy
terminals. These purists will clean/deoxidize all connections in a
controlled atmosphere, and dry them in completely dry nitrogen, or other
inert gas. The connections will then be used immediately during the
measurement and the purists will have assured themselves that all
instrument to lead connections are tight enough to be oxygen free.
Can anyone mention any precision metrology instrumentation in current
production with pure copper, or copper alloy connectors? I have a 38 year
old Hp 740b, and yep, it's got Gold flashed connectors. This Gold flashing
seems to be a tradition.
The practical metrologist, will accept the fact that precision metrology
instruments are meant to last many years, and the terminals supplied with
these instruments must provide a stable thermal emf profile over time.
Thus, they accept instruments that come with gold plated terminals. The
Gold may need to be cleansed of debris, and degreased from time-to-time,
but the procedure is much simpler, and not as time consuming as oxide
removal. The leads to these instruments are meant to be used day in, and
day out, as well. Therefore, the leads also terminate in some form of gold
plated connector. The practical metrologist is fastidious in controlling
temperature, and air movement in the lab, to minimize thermal unbalance in
his/her lash up.
Is this a foolish simplification of the thermals debate, or can I feel
vindicated using my homemade, gold plated lead terminations with my old
740b, and 731b?
On Wed, Aug 27, 2014 at 3:45 PM, M K m1k3k1@hotmail.com wrote:
On 26/08/2014 16:05, Mike S wrote:
After some more research, I think I've answered some of my own questions -
Tellurium copper is used for binding posts, not because it has any
special thermal or EMF mojo, but because it machines much better than pure
copper. And, I suppose, because it sounds like it's extra special.
The Seebeck coefficients (uV/C, relative to Cu) of some relevant
materials:
Cu 0.0
Ag .2
Au .5
Yellow brass 1.5
Phosphor bronze 2.0
63/37 solder 3.0
Sn 3.1
Stainless steel 3.1
Beryllium copper 5.0
Fe -12.3
Ni 22.3
Te -49.25
Based on the extreme Seebeck coefficient of pure tellurium vs. copper,
I'd expect that there might be some coefficient between Cu and CuTe (0.5%
Te), but I could find no reference. The relatively large number for CuBe is
interesting, since that's a common material for banana plug springs, where
one might expect the greatest temperature differential to occur in such a
connection (between the thermal masses of the binding post/jack and the
bulk of the banana plug). Heat has to flow a considerable distance through
the springs, very much more than when it flows through a surface plating.
The Pomona (Fluke) EM5295-48-0# uses CuBe (gold plated) for the spring
contacts. It seems there might be an improvement to be had by using the
older style pin plugs, where a solid pin was partially sliced into 4
sections which were then spread apart a bit to create tension. That could
eliminate relatively large thermocouples at a thermal gradient, and might
also be expected to have less thermal resistance, allowing the connection
to settle quicker.
But maybe not - I'm still not clear on how plated conductors behave in
this situation. For a high impedance voltage measurement where almost no
current flows, the gold plating may carry the signal, so there is no real
thermocouple (or more correctly, it's entirely contained within the
connector). But if that's the case, why fool around with special copper
connectors when common brass ones would be easier/cheaper? For current or
resistance, the signal would also flow through the base metal, so does this
have an effect (especially for tinned copper test leads, where there may be
a larger temperature difference between the ends???
Nickle is avoided as a contact material largely because it is subject to
fretting corrosion. Tests done by AMP (http://www.te.com/
documentation/whitepapers/pdf/p154-74.pdf) show that a Ni to Ni contact
can increase from 8 mOhm to 5 Ohms (sic!) in a short time due to this,
while Ag and Au plated contacts exhibit negligible changes.
Cu (with Be for better machining) seems to be used as the base material
for jacks/plugs to get thermal EMF cancellation to the wiring on both sides
(i.e. use copper everywhere except where there is a minimal thermal
gradient, like platings).
Beryllium copper is a springy material, Tellurium is the material added
to aid machining without adding too much seebeck coefficient.
I remember someone on this list a long time ago saying that NPL used van
damme star quad cable and bought bulk quantities of spade lugs that they
strip all the coating off before crimping and clean before each use.
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/volt-nuts
and follow the instructions there.
As a non-scholar in metrology, I tend to want to simplify the results of an
academic debate to make the results of the debate useful to me. One thing
is clear from my web search, copper alloyed with Tellurium, or Beryllium,
still oxidizes, only at a slower rate. It appears that a big disadvantage
of Beryllium oxide is its very hard, a useful industrial characteristic.
Not a nice property in the metrology lab.
Here goes:
For the purists with lab grade metallurgical abrasives, polishing
equipment, and oxide removal chemistry, only, copper, whether alloyed with
Beryllium or Tellurium is all they want to see in their lead terminations,
and they will try to procure only instruments with copper/copper alloy
terminals. These purists will clean/deoxidize all connections in a
controlled atmosphere, and dry them in completely dry nitrogen, or other
inert gas. The connections will then be used immediately during the
measurement and the purists will have assured themselves that all
instrument to lead connections are tight enough to be oxygen free.
Can anyone mention any precision metrology instrumentation in current
production with pure copper, or copper alloy connectors? I have a 38 year
old Hp 740b, and yep, it's got Gold flashed connectors. This Gold flashing
seems to be a tradition.
The practical metrologist, will accept the fact that precision metrology
instruments are meant to last many years, and the terminals supplied with
these instruments must provide a stable thermal emf profile over time.
Thus, they accept instruments that come with gold plated terminals. The
Gold may need to be cleansed of debris, and degreased from time-to-time,
but the procedure is much simpler, and not as time consuming as oxide
removal. The leads to these instruments are meant to be used day in, and
day out, as well. Therefore, the leads also terminate in some form of gold
plated connector. The practical metrologist is fastidious in controlling
temperature, and air movement in the lab, to minimize thermal unbalance in
his/her lash up.
Is this a foolish simplification of the thermals debate, or can I feel
vindicated using my homemade, gold plated lead terminations with my old
740b, and 731b?
On Wed, Aug 27, 2014 at 3:45 PM, M K <m1k3k1@hotmail.com> wrote:
> On 26/08/2014 16:05, Mike S wrote:
>
>> After some more research, I think I've answered some of my own questions -
>>
>> Tellurium copper is used for binding posts, not because it has any
>> special thermal or EMF mojo, but because it machines much better than pure
>> copper. And, I suppose, because it sounds like it's extra special.
>>
>> The Seebeck coefficients (uV/C, relative to Cu) of some relevant
>> materials:
>> Cu 0.0
>> Ag .2
>> Au .5
>> Yellow brass 1.5
>> Phosphor bronze 2.0
>> 63/37 solder 3.0
>> Sn 3.1
>> Stainless steel 3.1
>> Beryllium copper 5.0
>> Fe -12.3
>> Ni 22.3
>> Te -49.25
>>
>> Based on the extreme Seebeck coefficient of pure tellurium vs. copper,
>> I'd expect that there might be some coefficient between Cu and CuTe (0.5%
>> Te), but I could find no reference. The relatively large number for CuBe is
>> interesting, since that's a common material for banana plug springs, where
>> one might expect the greatest temperature differential to occur in such a
>> connection (between the thermal masses of the binding post/jack and the
>> bulk of the banana plug). Heat has to flow a considerable distance through
>> the springs, very much more than when it flows through a surface plating.
>>
>> The Pomona (Fluke) EM5295-48-0# uses CuBe (gold plated) for the spring
>> contacts. It seems there might be an improvement to be had by using the
>> older style pin plugs, where a solid pin was partially sliced into 4
>> sections which were then spread apart a bit to create tension. That could
>> eliminate relatively large thermocouples at a thermal gradient, and might
>> also be expected to have less thermal resistance, allowing the connection
>> to settle quicker.
>>
>> But maybe not - I'm still not clear on how plated conductors behave in
>> this situation. For a high impedance voltage measurement where almost no
>> current flows, the gold plating may carry the signal, so there is no real
>> thermocouple (or more correctly, it's entirely contained within the
>> connector). But if that's the case, why fool around with special copper
>> connectors when common brass ones would be easier/cheaper? For current or
>> resistance, the signal would also flow through the base metal, so does this
>> have an effect (especially for tinned copper test leads, where there may be
>> a larger temperature difference between the ends???
>>
>> Nickle is avoided as a contact material largely because it is subject to
>> fretting corrosion. Tests done by AMP (http://www.te.com/
>> documentation/whitepapers/pdf/p154-74.pdf) show that a Ni to Ni contact
>> can increase from 8 mOhm to 5 Ohms (sic!) in a short time due to this,
>> while Ag and Au plated contacts exhibit negligible changes.
>>
>> Cu (with Be for better machining) seems to be used as the base material
>> for jacks/plugs to get thermal EMF cancellation to the wiring on both sides
>> (i.e. use copper everywhere except where there is a minimal thermal
>> gradient, like platings).
>>
>> Beryllium copper is a springy material, Tellurium is the material added
> to aid machining without adding too much seebeck coefficient.
>
> I remember someone on this list a long time ago saying that NPL used van
> damme star quad cable and bought bulk quantities of spade lugs that they
> strip all the coating off before crimping and clean before each use.
>
> _______________________________________________
> volt-nuts mailing list -- volt-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/volt-nuts
> and follow the instructions there.
>
PK
Poul-Henning Kamp
Thu, Aug 28, 2014 6:02 AM
In message CAPmQ2J_Fa1Oo6m=Doj-u05f4dqHGpAKDvjpsvGgyroFe6Tj_Cg@mail.gmail.com
, Stan Katz writes:
real metrology purists keep their instruments in a pre helium atmosphere
to improve cooling, prevent corrosion and stop people from breathning on
things :-)
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
--------
In message <CAPmQ2J_Fa1Oo6m=Doj-u05f4dqHGpAKDvjpsvGgyroFe6Tj_Cg@mail.gmail.com>
, Stan Katz writes:
*real* metrology purists keep their instruments in a pre helium atmosphere
to improve cooling, prevent corrosion and stop people from breathning on
things :-)
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
A
acbern@gmx.de
Thu, Aug 28, 2014 8:07 AM
I do fully agree with you. this has become, to a big extent, an academic debate. it may be relavant if the resolution needs to be in the nv-range, such as working with josephson-elements. I guess nobody in this group here is.
to your question, yes, the 34420a and the 2182 nanovolt meters use pure copper contacts, and from time to time they should be cleaned with deoxit. I have not seen any issue with these connectors. would I use unplated (non-gold-surface) copper connectors if I had a choice. never. did i ever have an emf problem with my gold plated copper spades in use together with the 34420a and 3458a. no. so for me at least the answer is simple.
Gesendet: Mittwoch, 27. August 2014 um 23:50 Uhr
Von: "Stan Katz" stan.katz.hk@gmail.com
An: "Discussion of precise voltage measurement" volt-nuts@febo.com
Betreff: Re: [volt-nuts] 732A and Prologix received
As a non-scholar in metrology, I tend to want to simplify the results of an
academic debate to make the results of the debate useful to me. One thing
is clear from my web search, copper alloyed with Tellurium, or Beryllium,
still oxidizes, only at a slower rate. It appears that a big disadvantage
of Beryllium oxide is its very hard, a useful industrial characteristic.
Not a nice property in the metrology lab.
Here goes:
For the purists with lab grade metallurgical abrasives, polishing
equipment, and oxide removal chemistry, only, copper, whether alloyed with
Beryllium or Tellurium is all they want to see in their lead terminations,
and they will try to procure only instruments with copper/copper alloy
terminals. These purists will clean/deoxidize all connections in a
controlled atmosphere, and dry them in completely dry nitrogen, or other
inert gas. The connections will then be used immediately during the
measurement and the purists will have assured themselves that all
instrument to lead connections are tight enough to be oxygen free.
Can anyone mention any precision metrology instrumentation in current
production with pure copper, or copper alloy connectors? I have a 38 year
old Hp 740b, and yep, it's got Gold flashed connectors. This Gold flashing
seems to be a tradition.
The practical metrologist, will accept the fact that precision metrology
instruments are meant to last many years, and the terminals supplied with
these instruments must provide a stable thermal emf profile over time.
Thus, they accept instruments that come with gold plated terminals. The
Gold may need to be cleansed of debris, and degreased from time-to-time,
but the procedure is much simpler, and not as time consuming as oxide
removal. The leads to these instruments are meant to be used day in, and
day out, as well. Therefore, the leads also terminate in some form of gold
plated connector. The practical metrologist is fastidious in controlling
temperature, and air movement in the lab, to minimize thermal unbalance in
his/her lash up.
Is this a foolish simplification of the thermals debate, or can I feel
vindicated using my homemade, gold plated lead terminations with my old
740b, and 731b?
On Wed, Aug 27, 2014 at 3:45 PM, M K m1k3k1@hotmail.com wrote:
On 26/08/2014 16:05, Mike S wrote:
After some more research, I think I've answered some of my own questions -
Tellurium copper is used for binding posts, not because it has any
special thermal or EMF mojo, but because it machines much better than pure
copper. And, I suppose, because it sounds like it's extra special.
The Seebeck coefficients (uV/C, relative to Cu) of some relevant
materials:
Cu 0.0
Ag .2
Au .5
Yellow brass 1.5
Phosphor bronze 2.0
63/37 solder 3.0
Sn 3.1
Stainless steel 3.1
Beryllium copper 5.0
Fe -12.3
Ni 22.3
Te -49.25
Based on the extreme Seebeck coefficient of pure tellurium vs. copper,
I'd expect that there might be some coefficient between Cu and CuTe (0.5%
Te), but I could find no reference. The relatively large number for CuBe is
interesting, since that's a common material for banana plug springs, where
one might expect the greatest temperature differential to occur in such a
connection (between the thermal masses of the binding post/jack and the
bulk of the banana plug). Heat has to flow a considerable distance through
the springs, very much more than when it flows through a surface plating.
The Pomona (Fluke) EM5295-48-0# uses CuBe (gold plated) for the spring
contacts. It seems there might be an improvement to be had by using the
older style pin plugs, where a solid pin was partially sliced into 4
sections which were then spread apart a bit to create tension. That could
eliminate relatively large thermocouples at a thermal gradient, and might
also be expected to have less thermal resistance, allowing the connection
to settle quicker.
But maybe not - I'm still not clear on how plated conductors behave in
this situation. For a high impedance voltage measurement where almost no
current flows, the gold plating may carry the signal, so there is no real
thermocouple (or more correctly, it's entirely contained within the
connector). But if that's the case, why fool around with special copper
connectors when common brass ones would be easier/cheaper? For current or
resistance, the signal would also flow through the base metal, so does this
have an effect (especially for tinned copper test leads, where there may be
a larger temperature difference between the ends???
Nickle is avoided as a contact material largely because it is subject to
fretting corrosion. Tests done by AMP (http://www.te.com/
documentation/whitepapers/pdf/p154-74.pdf) show that a Ni to Ni contact
can increase from 8 mOhm to 5 Ohms (sic!) in a short time due to this,
while Ag and Au plated contacts exhibit negligible changes.
Cu (with Be for better machining) seems to be used as the base material
for jacks/plugs to get thermal EMF cancellation to the wiring on both sides
(i.e. use copper everywhere except where there is a minimal thermal
gradient, like platings).
Beryllium copper is a springy material, Tellurium is the material added
to aid machining without adding too much seebeck coefficient.
I remember someone on this list a long time ago saying that NPL used van
damme star quad cable and bought bulk quantities of spade lugs that they
strip all the coating off before crimping and clean before each use.
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/volt-nuts
and follow the instructions there.
I do fully agree with you. this has become, to a big extent, an academic debate. it may be relavant if the resolution needs to be in the nv-range, such as working with josephson-elements. I guess nobody in this group here is.
to your question, yes, the 34420a and the 2182 nanovolt meters use pure copper contacts, and from time to time they should be cleaned with deoxit. I have not seen any issue with these connectors. would I use unplated (non-gold-surface) copper connectors if I had a choice. never. did i ever have an emf problem with my gold plated copper spades in use together with the 34420a and 3458a. no. so for me at least the answer is simple.
> Gesendet: Mittwoch, 27. August 2014 um 23:50 Uhr
> Von: "Stan Katz" <stan.katz.hk@gmail.com>
> An: "Discussion of precise voltage measurement" <volt-nuts@febo.com>
> Betreff: Re: [volt-nuts] 732A and Prologix received
>
> As a non-scholar in metrology, I tend to want to simplify the results of an
> academic debate to make the results of the debate useful to me. One thing
> is clear from my web search, copper alloyed with Tellurium, or Beryllium,
> still oxidizes, only at a slower rate. It appears that a big disadvantage
> of Beryllium oxide is its very hard, a useful industrial characteristic.
> Not a nice property in the metrology lab.
>
> Here goes:
>
> For the purists with lab grade metallurgical abrasives, polishing
> equipment, and oxide removal chemistry, only, copper, whether alloyed with
> Beryllium or Tellurium is all they want to see in their lead terminations,
> and they will try to procure only instruments with copper/copper alloy
> terminals. These purists will clean/deoxidize all connections in a
> controlled atmosphere, and dry them in completely dry nitrogen, or other
> inert gas. The connections will then be used immediately during the
> measurement and the purists will have assured themselves that all
> instrument to lead connections are tight enough to be oxygen free.
>
> Can anyone mention any precision metrology instrumentation in current
> production with pure copper, or copper alloy connectors? I have a 38 year
> old Hp 740b, and yep, it's got Gold flashed connectors. This Gold flashing
> seems to be a tradition.
>
> The practical metrologist, will accept the fact that precision metrology
> instruments are meant to last many years, and the terminals supplied with
> these instruments must provide a stable thermal emf profile over time.
> Thus, they accept instruments that come with gold plated terminals. The
> Gold may need to be cleansed of debris, and degreased from time-to-time,
> but the procedure is much simpler, and not as time consuming as oxide
> removal. The leads to these instruments are meant to be used day in, and
> day out, as well. Therefore, the leads also terminate in some form of gold
> plated connector. The practical metrologist is fastidious in controlling
> temperature, and air movement in the lab, to minimize thermal unbalance in
> his/her lash up.
>
> Is this a foolish simplification of the thermals debate, or can I feel
> vindicated using my homemade, gold plated lead terminations with my old
> 740b, and 731b?
>
>
> On Wed, Aug 27, 2014 at 3:45 PM, M K <m1k3k1@hotmail.com> wrote:
>
> > On 26/08/2014 16:05, Mike S wrote:
> >
> >> After some more research, I think I've answered some of my own questions -
> >>
> >> Tellurium copper is used for binding posts, not because it has any
> >> special thermal or EMF mojo, but because it machines much better than pure
> >> copper. And, I suppose, because it sounds like it's extra special.
> >>
> >> The Seebeck coefficients (uV/C, relative to Cu) of some relevant
> >> materials:
> >> Cu 0.0
> >> Ag .2
> >> Au .5
> >> Yellow brass 1.5
> >> Phosphor bronze 2.0
> >> 63/37 solder 3.0
> >> Sn 3.1
> >> Stainless steel 3.1
> >> Beryllium copper 5.0
> >> Fe -12.3
> >> Ni 22.3
> >> Te -49.25
> >>
> >> Based on the extreme Seebeck coefficient of pure tellurium vs. copper,
> >> I'd expect that there might be some coefficient between Cu and CuTe (0.5%
> >> Te), but I could find no reference. The relatively large number for CuBe is
> >> interesting, since that's a common material for banana plug springs, where
> >> one might expect the greatest temperature differential to occur in such a
> >> connection (between the thermal masses of the binding post/jack and the
> >> bulk of the banana plug). Heat has to flow a considerable distance through
> >> the springs, very much more than when it flows through a surface plating.
> >>
> >> The Pomona (Fluke) EM5295-48-0# uses CuBe (gold plated) for the spring
> >> contacts. It seems there might be an improvement to be had by using the
> >> older style pin plugs, where a solid pin was partially sliced into 4
> >> sections which were then spread apart a bit to create tension. That could
> >> eliminate relatively large thermocouples at a thermal gradient, and might
> >> also be expected to have less thermal resistance, allowing the connection
> >> to settle quicker.
> >>
> >> But maybe not - I'm still not clear on how plated conductors behave in
> >> this situation. For a high impedance voltage measurement where almost no
> >> current flows, the gold plating may carry the signal, so there is no real
> >> thermocouple (or more correctly, it's entirely contained within the
> >> connector). But if that's the case, why fool around with special copper
> >> connectors when common brass ones would be easier/cheaper? For current or
> >> resistance, the signal would also flow through the base metal, so does this
> >> have an effect (especially for tinned copper test leads, where there may be
> >> a larger temperature difference between the ends???
> >>
> >> Nickle is avoided as a contact material largely because it is subject to
> >> fretting corrosion. Tests done by AMP (http://www.te.com/
> >> documentation/whitepapers/pdf/p154-74.pdf) show that a Ni to Ni contact
> >> can increase from 8 mOhm to 5 Ohms (sic!) in a short time due to this,
> >> while Ag and Au plated contacts exhibit negligible changes.
> >>
> >> Cu (with Be for better machining) seems to be used as the base material
> >> for jacks/plugs to get thermal EMF cancellation to the wiring on both sides
> >> (i.e. use copper everywhere except where there is a minimal thermal
> >> gradient, like platings).
> >>
> >> Beryllium copper is a springy material, Tellurium is the material added
> > to aid machining without adding too much seebeck coefficient.
> >
> > I remember someone on this list a long time ago saying that NPL used van
> > damme star quad cable and bought bulk quantities of spade lugs that they
> > strip all the coating off before crimping and clean before each use.
> >
> > _______________________________________________
> > volt-nuts mailing list -- volt-nuts@febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> > mailman/listinfo/volt-nuts
> > and follow the instructions there.
> >
> _______________________________________________
> volt-nuts mailing list -- volt-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> and follow the instructions there.
CB
Charles Black
Fri, Aug 29, 2014 12:39 AM
CB
Charles Black
Fri, Aug 29, 2014 8:36 PM
CB
Charles Black
Fri, Aug 29, 2014 8:44 PM
Hi Don,
I'm a bit of trouble sending you this message for some reason. Maybe the
third ti me is the charm.
Thanks for sharing the graph a few days ago. My 3458A graphs look about
the same except I only do voltage so far. I use NPLC 1000 which looks
smoother but doesn't really have any additional useful info. I have been
meaning to have my TEMP? servoed some time in the near future. My TEMP?
runs about 37C at a room temp of 23C. Is your room temp a bit higher?
Charlie
On 8/29/2014 1:36 PM, Charles Black wrote:
Hi Don,
I'm a bit of trouble sending you this message for some reason. Maybe the
third ti me is the charm.
Thanks for sharing the graph a few days ago. My 3458A graphs look about
the same except I only do voltage so far. I use NPLC 1000 which looks
smoother but doesn't really have any additional useful info. I have been
meaning to have my TEMP? servoed some time in the near future. My TEMP?
runs about 37C at a room temp of 23C. Is your room temp a bit higher?
Charlie
On 8/29/2014 1:36 PM, Charles Black wrote:
> _______________________________________________
> volt-nuts mailing list -- volt-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> and follow the instructions there.
>
>
>
D
Don@True-Cal
Sat, Aug 30, 2014 3:09 PM
Hi Charlie,
Yes, in the summer time my lab runs between ~24.5 & 26.5 C with an occasional excursion beyond either of those limits on extreme days. It is a basement (walkout type) lab with ceramic tile floor which helps account for the muted extremes, and also not having an extreme hot or cold attic overhead. See the link for a lab temperature graph over several days including the last day of the summer voltage run I provided earlier. Since the 3458A accuracy is +/- ~0.5 PPM over typical lab temp extremes, I maintain a database of lab temp, 3458A ref 10.0V readings and 3458A internal temp so I can always refer back if doing a critical voltage transfer. The computer program not only does the graphing but also logs the raw data. While logging, I use lower (100 or 200) NPLC settings so my raw data resolution provides more detail for other types of post processing. But even when doing a voltage transfer, I never see an advantage, and don't use an NPLC setting over 300 (5-min). I would love to maintain the standard 23C lab temp but in the summer months here in the Midwest US, that gets too expensive. Winter temperatures are centered fairly close to 23C. The lab temperature graph link shows four PRT sensors, one is simply in open air thus subject to the same air currents as all instruments while the remaining three are in two different temperature dry-wells (powered off of course) that contribute considerable thermal mass.
https://www.dropbox.com/s/r5vl3v0k3s9t8n1/Lab%20Temp%208-22%20to%208-30%202014.pdf?dl=0
Don
-----Original Message-----
From: volt-nuts [mailto:volt-nuts-bounces@febo.com] On Behalf Of Charles Black
Sent: Friday, August 29, 2014 3:44 PM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] 732A and Prologix received
Hi Don,
I'm a bit of trouble sending you this message for some reason. Maybe the third ti me is the charm.
Thanks for sharing the graph a few days ago. My 3458A graphs look about the same except I only do voltage so far. I use NPLC 1000 which looks smoother but doesn't really have any additional useful info. I have been meaning to have my TEMP? servoed some time in the near future. My TEMP?
runs about 37C at a room temp of 23C. Is your room temp a bit higher?
Charlie
On 8/29/2014 1:36 PM, Charles Black wrote:
Hi Charlie,
Yes, in the summer time my lab runs between ~24.5 & 26.5 C with an occasional excursion beyond either of those limits on extreme days. It is a basement (walkout type) lab with ceramic tile floor which helps account for the muted extremes, and also not having an extreme hot or cold attic overhead. See the link for a lab temperature graph over several days including the last day of the summer voltage run I provided earlier. Since the 3458A accuracy is +/- ~0.5 PPM over typical lab temp extremes, I maintain a database of lab temp, 3458A ref 10.0V readings and 3458A internal temp so I can always refer back if doing a critical voltage transfer. The computer program not only does the graphing but also logs the raw data. While logging, I use lower (100 or 200) NPLC settings so my raw data resolution provides more detail for other types of post processing. But even when doing a voltage transfer, I never see an advantage, and don't use an NPLC setting over 300 (5-min). I would love to maintain the standard 23C lab temp but in the summer months here in the Midwest US, that gets too expensive. Winter temperatures are centered fairly close to 23C. The lab temperature graph link shows four PRT sensors, one is simply in open air thus subject to the same air currents as all instruments while the remaining three are in two different temperature dry-wells (powered off of course) that contribute considerable thermal mass.
https://www.dropbox.com/s/r5vl3v0k3s9t8n1/Lab%20Temp%208-22%20to%208-30%202014.pdf?dl=0
Don
-----Original Message-----
From: volt-nuts [mailto:volt-nuts-bounces@febo.com] On Behalf Of Charles Black
Sent: Friday, August 29, 2014 3:44 PM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] 732A and Prologix received
Hi Don,
I'm a bit of trouble sending you this message for some reason. Maybe the third ti me is the charm.
Thanks for sharing the graph a few days ago. My 3458A graphs look about the same except I only do voltage so far. I use NPLC 1000 which looks smoother but doesn't really have any additional useful info. I have been meaning to have my TEMP? servoed some time in the near future. My TEMP?
runs about 37C at a room temp of 23C. Is your room temp a bit higher?
Charlie
On 8/29/2014 1:36 PM, Charles Black wrote:
> _______________________________________________
> volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> and follow the instructions there.
>
>
>
_______________________________________________
volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
