DF
Dr. Frank Stellmach
Sun, Nov 30, 2008 3:18 PM
Hello,
there's currently no easy way to convert a frequency into Volt, i.e.
other than by cryo Josephson junction array or realizing Ohm by a
Klitzing quantum hall effect device. Otherwise, FLUKE would have
implemented that already in their Calibrators/Standards. They still rely
on Artefact Calibration, i.e. ovenized longterm stable Zener References
and Reference Resistors.
The 5720A uses a stacked double Zener reference on a proprietary hybrid
circuitry, giving 1-2 ppm/year stability, the 7001 and 732B use the
LTZ1000 (Zener above BE junction), as the 3458A, the 732A uses the
Motorola device (Zener below BE junction), and the elder 332D and 335D
use similar, but less longterm stable references.
The LM199, AD587 and I think also the Geller device may only be used as
transfer standards, having poor longterm stabilities of 20ppm/yr. or more.
Therefore, the LTZ1000 only may serve as a really affordable standard,
i.e. below 8ppm longterm stability, for private use.
I was lucky to get some LTZ1000 samples, and used the standard circuit
from the LT datasheet for creating a small PCB. I purchased commercially
available wire wound resistors (TK 3, 25ppm/yr) for the 5 necessary
reference resistors and two OP07. Those resistors should give less than
TK 1 and 1ppm/yr additional drifts.
Compared to my HP34401A, the circuitry showed quite good short term
stability below 1ppm, but shielding still has to be improved, as the
LTZ1000 circuit is susceptible to external EMC disturbances. This Volt
reference then costs less than 100 Euros/Dollars in total.
I designed further circuitry (with TK 0.3 and TK 0.1 precision metal
foil resistors from Alpha and Vishay, chopper amp, precision switches
and Teflon insulated wires) to have the possibility for precision
transfers of the 7,2V reference voltage to 100mV, 1V, 10V, 100V, 1000V
level.
Only then, a Volt Standard is complete.
All this stuff will emulate or replace the commonly needed 732A (ref),
720A (Kelvin Varley), 752A (Reference Divider) and 834B (Null Detector).
Got no time yet to finish and improve the system, and to do the repair
on an old 332B standard, but would like to share my knowledge, if
anyone's interested.
Frank Stellmach
Hello,
there's currently no easy way to convert a frequency into Volt, i.e.
other than by cryo Josephson junction array or realizing Ohm by a
Klitzing quantum hall effect device. Otherwise, FLUKE would have
implemented that already in their Calibrators/Standards. They still rely
on Artefact Calibration, i.e. ovenized longterm stable Zener References
and Reference Resistors.
The 5720A uses a stacked double Zener reference on a proprietary hybrid
circuitry, giving 1-2 ppm/year stability, the 7001 and 732B use the
LTZ1000 (Zener above BE junction), as the 3458A, the 732A uses the
Motorola device (Zener below BE junction), and the elder 332D and 335D
use similar, but less longterm stable references.
The LM199, AD587 and I think also the Geller device may only be used as
transfer standards, having poor longterm stabilities of 20ppm/yr. or more.
Therefore, the LTZ1000 only may serve as a really affordable standard,
i.e. below 8ppm longterm stability, for private use.
I was lucky to get some LTZ1000 samples, and used the standard circuit
from the LT datasheet for creating a small PCB. I purchased commercially
available wire wound resistors (TK 3, 25ppm/yr) for the 5 necessary
reference resistors and two OP07. Those resistors should give less than
TK 1 and 1ppm/yr additional drifts.
Compared to my HP34401A, the circuitry showed quite good short term
stability below 1ppm, but shielding still has to be improved, as the
LTZ1000 circuit is susceptible to external EMC disturbances. This Volt
reference then costs less than 100 Euros/Dollars in total.
I designed further circuitry (with TK 0.3 and TK 0.1 precision metal
foil resistors from Alpha and Vishay, chopper amp, precision switches
and Teflon insulated wires) to have the possibility for precision
transfers of the 7,2V reference voltage to 100mV, 1V, 10V, 100V, 1000V
level.
Only then, a Volt Standard is complete.
All this stuff will emulate or replace the commonly needed 732A (ref),
720A (Kelvin Varley), 752A (Reference Divider) and 834B (Null Detector).
Got no time yet to finish and improve the system, and to do the repair
on an old 332B standard, but would like to share my knowledge, if
anyone's interested.
Frank Stellmach
W
wje
Sun, Nov 30, 2008 3:35 PM
Another (sometimes) relatively inexpensive outstanding reference is
either a Datron 4910 or 4912. These are also LTZ1000 based. The 10 has
one reference, the 12 has four that can be averaged or used
independently. You can on rare occasions pick one up for a few hundred.
I have a pair, and yes, I paid Fluke $600 for traceable certification
for one.
These use a rather clever way of generating 1V and 1.18 volts without
significant division error. The 10V reference is sampled by a
pulse-width modulator whose duty cycle is crystal-controlled and
programmable. The result is then LP filtered using an active filter and
tracks the primary reference to better than 1ppm.
My primary one was hot-shipped from Fluke after certification (it has
battery backup) and hasn't ever been turned off. I have turned the
secondary one on and off a few times, and the resultant error is less
than 0.3 ppm. Both of these units had thousands of hours of burn-in
before I got them, and I've added another 30 thousand or so.
I also have a Solartron 7081 8.5 digit meter, which is a marvelous unit.
It uses a selected ultra-low TC Zener with a transistor for temp
compensation, a sort-of discrete implementation of the LTZ1000. The
Zener current is programmable, and is used to set the zero point for the
particular zener/transistor pair. I can turn mine off for months at a
time, turn it back on, and after a 24 h warmup, usually have it within
1ppm(!) of my primary ref. These are somewhat rare, but can be picked up
for a few hundreds. I paid $300 for mine.
As for why, I'm surprised that no one has stated the obvious reason -
because you can. It's the same reason time-nuts collect 10e-13 frequency
standards. I was into precision voltage and resistance metrology well
before I got into precision frequency. I find it fascinating to be able
to determine various values to precisions that not all that long ago
were limited to national standards labs.
Bill Ezell
They said 'Windows or better'
so I used Linux.
Dr. Frank Stellmach wrote:
Hello,
there's currently no easy way to convert a frequency into Volt, i.e.
other than by cryo Josephson junction array or realizing Ohm by a
Klitzing quantum hall effect device. Otherwise, FLUKE would have
implemented that already in their Calibrators/Standards. They still rely
on Artefact Calibration, i.e. ovenized longterm stable Zener References
and Reference Resistors.
The 5720A uses a stacked double Zener reference on a proprietary hybrid
circuitry, giving 1-2 ppm/year stability, the 7001 and 732B use the
LTZ1000 (Zener above BE junction), as the 3458A, the 732A uses the
Motorola device (Zener below BE junction), and the elder 332D and 335D
use similar, but less longterm stable references.
The LM199, AD587 and I think also the Geller device may only be used as
transfer standards, having poor longterm stabilities of 20ppm/yr. or more.
Therefore, the LTZ1000 only may serve as a really affordable standard,
i.e. below 8ppm longterm stability, for private use.
I was lucky to get some LTZ1000 samples, and used the standard circuit
from the LT datasheet for creating a small PCB. I purchased commercially
available wire wound resistors (TK 3, 25ppm/yr) for the 5 necessary
reference resistors and two OP07. Those resistors should give less than
TK 1 and 1ppm/yr additional drifts.
Compared to my HP34401A, the circuitry showed quite good short term
stability below 1ppm, but shielding still has to be improved, as the
LTZ1000 circuit is susceptible to external EMC disturbances. This Volt
reference then costs less than 100 Euros/Dollars in total.
I designed further circuitry (with TK 0.3 and TK 0.1 precision metal
foil resistors from Alpha and Vishay, chopper amp, precision switches
and Teflon insulated wires) to have the possibility for precision
transfers of the 7,2V reference voltage to 100mV, 1V, 10V, 100V, 1000V
level.
Only then, a Volt Standard is complete.
All this stuff will emulate or replace the commonly needed 732A (ref),
720A (Kelvin Varley), 752A (Reference Divider) and 834B (Null Detector).
Got no time yet to finish and improve the system, and to do the repair
on an old 332B standard, but would like to share my knowledge, if
anyone's interested.
Frank Stellmach
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Another (sometimes) relatively inexpensive outstanding reference is
either a Datron 4910 or 4912. These are also LTZ1000 based. The 10 has
one reference, the 12 has four that can be averaged or used
independently. You can on rare occasions pick one up for a few hundred.
I have a pair, and yes, I paid Fluke $600 for traceable certification
for one.
These use a rather clever way of generating 1V and 1.18 volts without
significant division error. The 10V reference is sampled by a
pulse-width modulator whose duty cycle is crystal-controlled and
programmable. The result is then LP filtered using an active filter and
tracks the primary reference to better than 1ppm.
My primary one was hot-shipped from Fluke after certification (it has
battery backup) and hasn't ever been turned off. I have turned the
secondary one on and off a few times, and the resultant error is less
than 0.3 ppm. Both of these units had thousands of hours of burn-in
before I got them, and I've added another 30 thousand or so.
I also have a Solartron 7081 8.5 digit meter, which is a marvelous unit.
It uses a selected ultra-low TC Zener with a transistor for temp
compensation, a sort-of discrete implementation of the LTZ1000. The
Zener current is programmable, and is used to set the zero point for the
particular zener/transistor pair. I can turn mine off for months at a
time, turn it back on, and after a 24 h warmup, usually have it within
1ppm(!) of my primary ref. These are somewhat rare, but can be picked up
for a few hundreds. I paid $300 for mine.
As for why, I'm surprised that no one has stated the obvious reason -
because you can. It's the same reason time-nuts collect 10e-13 frequency
standards. I was into precision voltage and resistance metrology well
before I got into precision frequency. I find it fascinating to be able
to determine various values to precisions that not all that long ago
were limited to national standards labs.
Bill Ezell
----------
They said 'Windows or better'
so I used Linux.
Dr. Frank Stellmach wrote:
> Hello,
>
> there's currently no easy way to convert a frequency into Volt, i.e.
> other than by cryo Josephson junction array or realizing Ohm by a
> Klitzing quantum hall effect device. Otherwise, FLUKE would have
> implemented that already in their Calibrators/Standards. They still rely
> on Artefact Calibration, i.e. ovenized longterm stable Zener References
> and Reference Resistors.
>
> The 5720A uses a stacked double Zener reference on a proprietary hybrid
> circuitry, giving 1-2 ppm/year stability, the 7001 and 732B use the
> LTZ1000 (Zener above BE junction), as the 3458A, the 732A uses the
> Motorola device (Zener below BE junction), and the elder 332D and 335D
> use similar, but less longterm stable references.
> The LM199, AD587 and I think also the Geller device may only be used as
> transfer standards, having poor longterm stabilities of 20ppm/yr. or more.
>
> Therefore, the LTZ1000 only may serve as a really affordable standard,
> i.e. below 8ppm longterm stability, for private use.
>
> I was lucky to get some LTZ1000 samples, and used the standard circuit
> from the LT datasheet for creating a small PCB. I purchased commercially
> available wire wound resistors (TK 3, 25ppm/yr) for the 5 necessary
> reference resistors and two OP07. Those resistors should give less than
> TK 1 and 1ppm/yr additional drifts.
>
> Compared to my HP34401A, the circuitry showed quite good short term
> stability below 1ppm, but shielding still has to be improved, as the
> LTZ1000 circuit is susceptible to external EMC disturbances. This Volt
> reference then costs less than 100 Euros/Dollars in total.
>
> I designed further circuitry (with TK 0.3 and TK 0.1 precision metal
> foil resistors from Alpha and Vishay, chopper amp, precision switches
> and Teflon insulated wires) to have the possibility for precision
> transfers of the 7,2V reference voltage to 100mV, 1V, 10V, 100V, 1000V
> level.
> Only then, a Volt Standard is complete.
>
> All this stuff will emulate or replace the commonly needed 732A (ref),
> 720A (Kelvin Varley), 752A (Reference Divider) and 834B (Null Detector).
>
> Got no time yet to finish and improve the system, and to do the repair
> on an old 332B standard, but would like to share my knowledge, if
> anyone's interested.
>
> Frank Stellmach
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
>
DF
Dr. Frank Stellmach
Sun, Nov 30, 2008 5:29 PM
@Bill Ezell:
Well, I have the same motivation to invest time and money into "precision".
I started with metrology working in a German Airforce cal lab in 1980.
We had all that goddie equipment, ie. a bank of Weston standard cells,
the Fluke cal system, DCF receiver, a HP caesium standard, and so on.
This cal lab was tightly associated with our PTB.
In a "secret" lab they obviously made some tests on the new Josephson
junction standard, as they transferred the Volt from this lab to our
facility with a Fluke 731A, and they were very proud of that.
From then on, the ppm quest never let me go.
It's biggest fun for me to design standards on my own, not only to
collect and repair old ones.
I've already read about the Datron standards, but didn't know details,
and that it's so sophisticated. It's inner principle of dividing the
reference is identical to the Fluke 5720A, I think.
Do you have a detailed schematic of the LTZ reference circuitry in the
Datron?
This cannot be found in the manuals of HP3458 or Fluke 7000.
In Germany there is no big chance for getting surplus standards for a
reasonable price.
It's a pity..
Frank
@Bill Ezell:
Well, I have the same motivation to invest time and money into "precision".
I started with metrology working in a German Airforce cal lab in 1980.
We had all that goddie equipment, ie. a bank of Weston standard cells,
the Fluke cal system, DCF receiver, a HP caesium standard, and so on.
This cal lab was tightly associated with our PTB.
In a "secret" lab they obviously made some tests on the new Josephson
junction standard, as they transferred the Volt from this lab to our
facility with a Fluke 731A, and they were very proud of that.
From then on, the ppm quest never let me go.
It's biggest fun for me to design standards on my own, not only to
collect and repair old ones.
I've already read about the Datron standards, but didn't know details,
and that it's so sophisticated. It's inner principle of dividing the
reference is identical to the Fluke 5720A, I think.
Do you have a detailed schematic of the LTZ reference circuitry in the
Datron?
This cannot be found in the manuals of HP3458 or Fluke 7000.
In Germany there is no big chance for getting surplus standards for a
reasonable price.
It's a pity..
Frank
W
wje
Sun, Nov 30, 2008 6:25 PM
Yes, I do have full schematics for the Datron refs, including the
LTZ1000 circuitry. It isn't the same as that in the LTZ1000 data sheet.
I'll dig out my manuals. If you'd like a copy, email your postal address
and I'll copy the page and send it to you:
wje@quackers.net
I've built a few standards myself. My latest was one using 16 399's. I
shamelessly stole some circuit designs from a Fluke reference to provide
sense-current compensation, etc. It was a lot of fun.
Bill Ezell
They said 'Windows or better'
so I used Linux.
Dr. Frank Stellmach wrote:
@Bill Ezell:
Well, I have the same motivation to invest time and money into "precision".
I started with metrology working in a German Airforce cal lab in 1980.
We had all that goddie equipment, ie. a bank of Weston standard cells,
the Fluke cal system, DCF receiver, a HP caesium standard, and so on.
This cal lab was tightly associated with our PTB.
In a "secret" lab they obviously made some tests on the new Josephson
junction standard, as they transferred the Volt from this lab to our
facility with a Fluke 731A, and they were very proud of that.
From then on, the ppm quest never let me go.
It's biggest fun for me to design standards on my own, not only to
collect and repair old ones.
I've already read about the Datron standards, but didn't know details,
and that it's so sophisticated. It's inner principle of dividing the
reference is identical to the Fluke 5720A, I think.
Do you have a detailed schematic of the LTZ reference circuitry in the
Datron?
This cannot be found in the manuals of HP3458 or Fluke 7000.
In Germany there is no big chance for getting surplus standards for a
reasonable price.
It's a pity..
Frank
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Yes, I do have full schematics for the Datron refs, including the
LTZ1000 circuitry. It isn't the same as that in the LTZ1000 data sheet.
I'll dig out my manuals. If you'd like a copy, email your postal address
and I'll copy the page and send it to you:
wje@quackers.net
I've built a few standards myself. My latest was one using 16 399's. I
shamelessly stole some circuit designs from a Fluke reference to provide
sense-current compensation, etc. It was a lot of fun.
Bill Ezell
----------
They said 'Windows or better'
so I used Linux.
Dr. Frank Stellmach wrote:
> @Bill Ezell:
>
> Well, I have the same motivation to invest time and money into "precision".
>
> I started with metrology working in a German Airforce cal lab in 1980.
> We had all that goddie equipment, ie. a bank of Weston standard cells,
> the Fluke cal system, DCF receiver, a HP caesium standard, and so on.
> This cal lab was tightly associated with our PTB.
> In a "secret" lab they obviously made some tests on the new Josephson
> junction standard, as they transferred the Volt from this lab to our
> facility with a Fluke 731A, and they were very proud of that.
>
> From then on, the ppm quest never let me go.
> It's biggest fun for me to design standards on my own, not only to
> collect and repair old ones.
>
> I've already read about the Datron standards, but didn't know details,
> and that it's so sophisticated. It's inner principle of dividing the
> reference is identical to the Fluke 5720A, I think.
>
> Do you have a detailed schematic of the LTZ reference circuitry in the
> Datron?
> This cannot be found in the manuals of HP3458 or Fluke 7000.
>
> In Germany there is no big chance for getting surplus standards for a
> reasonable price.
> It's a pity..
>
> Frank
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
>
PD
Predrag Dukic
Mon, Dec 1, 2008 1:24 AM
Obsession for precision is the same whether one is after Hertz,
Volts, or Degrees of Celsius (Or Fahrenheit).
The methods and technology are similar...
I am now trying to fix two HP2804A quarz thermometers, thet are
giving some error codes, and do not work.
More or less they are oscillators, and measure of temperature is
measured by frequency shift between reference and external oscillator.
Reference frequency is unusual 10.000.000,8 in one of them (marked
exactly so) and 10.000.001 in the other.
(Yes, yes, not a typo: it is 10MHz plus 0.8 Hz or plus 1.0 Hz)
So precise temperature and precise frequency cross their ways...
By the way, does anybody have op/serv manual for this thermometer?
Predrag Dukic
At 16:18 30.11.2008, you wrote:
Hello,
there's currently no easy way to convert a frequency into Volt, i.e.
other than by cryo Josephson junction array or realizing Ohm by a
Klitzing quantum hall effect device. Otherwise, FLUKE would have
implemented that already in their Calibrators/Standards. They still rely
on Artefact Calibration, i.e. ovenized longterm stable Zener References
and Reference Resistors.
The 5720A uses a stacked double Zener reference on a proprietary hybrid
circuitry, giving 1-2 ppm/year stability, the 7001 and 732B use the
LTZ1000 (Zener above BE junction), as the 3458A, the 732A uses the
Motorola device (Zener below BE junction), and the elder 332D and 335D
use similar, but less longterm stable references.
The LM199, AD587 and I think also the Geller device may only be used as
transfer standards, having poor longterm stabilities of 20ppm/yr. or more.
Therefore, the LTZ1000 only may serve as a really affordable standard,
i.e. below 8ppm longterm stability, for private use.
I was lucky to get some LTZ1000 samples, and used the standard circuit
from the LT datasheet for creating a small PCB. I purchased commercially
available wire wound resistors (TK 3, 25ppm/yr) for the 5 necessary
reference resistors and two OP07. Those resistors should give less than
TK 1 and 1ppm/yr additional drifts.
Compared to my HP34401A, the circuitry showed quite good short term
stability below 1ppm, but shielding still has to be improved, as the
LTZ1000 circuit is susceptible to external EMC disturbances. This Volt
reference then costs less than 100 Euros/Dollars in total.
I designed further circuitry (with TK 0.3 and TK 0.1 precision metal
foil resistors from Alpha and Vishay, chopper amp, precision switches
and Teflon insulated wires) to have the possibility for precision
transfers of the 7,2V reference voltage to 100mV, 1V, 10V, 100V, 1000V
level.
Only then, a Volt Standard is complete.
All this stuff will emulate or replace the commonly needed 732A (ref),
720A (Kelvin Varley), 752A (Reference Divider) and 834B (Null Detector).
Got no time yet to finish and improve the system, and to do the repair
on an old 332B standard, but would like to share my knowledge, if
anyone's interested.
Frank Stellmach
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Obsession for precision is the same whether one is after Hertz,
Volts, or Degrees of Celsius (Or Fahrenheit).
The methods and technology are similar...
I am now trying to fix two HP2804A quarz thermometers, thet are
giving some error codes, and do not work.
More or less they are oscillators, and measure of temperature is
measured by frequency shift between reference and external oscillator.
Reference frequency is unusual 10.000.000,8 in one of them (marked
exactly so) and 10.000.001 in the other.
(Yes, yes, not a typo: it is 10MHz plus 0.8 Hz or plus 1.0 Hz)
So precise temperature and precise frequency cross their ways...
By the way, does anybody have op/serv manual for this thermometer?
Predrag Dukic
At 16:18 30.11.2008, you wrote:
>Hello,
>
>there's currently no easy way to convert a frequency into Volt, i.e.
>other than by cryo Josephson junction array or realizing Ohm by a
>Klitzing quantum hall effect device. Otherwise, FLUKE would have
>implemented that already in their Calibrators/Standards. They still rely
>on Artefact Calibration, i.e. ovenized longterm stable Zener References
>and Reference Resistors.
>
>The 5720A uses a stacked double Zener reference on a proprietary hybrid
>circuitry, giving 1-2 ppm/year stability, the 7001 and 732B use the
>LTZ1000 (Zener above BE junction), as the 3458A, the 732A uses the
>Motorola device (Zener below BE junction), and the elder 332D and 335D
>use similar, but less longterm stable references.
>The LM199, AD587 and I think also the Geller device may only be used as
>transfer standards, having poor longterm stabilities of 20ppm/yr. or more.
>
>Therefore, the LTZ1000 only may serve as a really affordable standard,
>i.e. below 8ppm longterm stability, for private use.
>
>I was lucky to get some LTZ1000 samples, and used the standard circuit
>from the LT datasheet for creating a small PCB. I purchased commercially
>available wire wound resistors (TK 3, 25ppm/yr) for the 5 necessary
>reference resistors and two OP07. Those resistors should give less than
>TK 1 and 1ppm/yr additional drifts.
>
>Compared to my HP34401A, the circuitry showed quite good short term
>stability below 1ppm, but shielding still has to be improved, as the
>LTZ1000 circuit is susceptible to external EMC disturbances. This Volt
>reference then costs less than 100 Euros/Dollars in total.
>
>I designed further circuitry (with TK 0.3 and TK 0.1 precision metal
>foil resistors from Alpha and Vishay, chopper amp, precision switches
>and Teflon insulated wires) to have the possibility for precision
>transfers of the 7,2V reference voltage to 100mV, 1V, 10V, 100V, 1000V
>level.
>Only then, a Volt Standard is complete.
>
>All this stuff will emulate or replace the commonly needed 732A (ref),
>720A (Kelvin Varley), 752A (Reference Divider) and 834B (Null Detector).
>
>Got no time yet to finish and improve the system, and to do the repair
>on an old 332B standard, but would like to share my knowledge, if
>anyone's interested.
>
>Frank Stellmach
>
>_______________________________________________
>time-nuts mailing list -- time-nuts@febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.
NM
Neville Michie
Mon, Dec 1, 2008 4:25 AM
Hi,
Temperature is one quantity that is (or was) determined by physical
properties of substances.
I have a platinum resistance thermometer, but alone it is useless.
The simplest way of using it is to connect it in 4 wire mode to a HP
3468A multimeter,
and it measures the resistance with a resolution of about 1mK.
Connect it to another HP 3468A and it varies by less than 1mK.
So the HP 3468A measurement is robust.
Use a widely disseminated formula for the resistance of thermal pure
platinum
and it seems to measure temperature.
Construct an ice-point cell with a dewar flask, shaved ice, a
stirring rod and a syphon tube
and we seem to have calibration to better than 10mK.
I then built a hypsometer to boil water in.
The temperature of the steam did not shift 1mK in several hours.
But you have to use a barometer (Fortin pattern) to find the
atmospheric pressure,
correct for the density of mercury,
correct for the expansion of the scale,
get an estimate for local gravity from
the Geoid, apply an altitude correction.
The result was that a $10 platinum resistance thermometer seems to be
accurate to 1mK
but the ice-point calibration uncertainty may add plus or minus 5mK.
The big difficulty with temperature measurement is that you need
circulating thermostat
baths to immerse things in to compare temperatures to any accuracy.
You only need
one or two of those in your shack to have no room for your time
standards, voltage standards etc.
cheers, Neville Michie
On 01/12/2008, at 12:24 PM, Predrag Dukic wrote:
Obsession for precision is the same whether one is after Hertz,
Volts, or Degrees of Celsius (Or Fahrenheit).
The methods and technology are similar...
I am now trying to fix two HP2804A quarz thermometers, thet are
giving some error codes, and do not work.
More or less they are oscillators, and measure of temperature is
measured by frequency shift between reference and external
oscillator.
Reference frequency is unusual 10.000.000,8 in one of them (marked
exactly so) and 10.000.001 in the other.
(Yes, yes, not a typo: it is 10MHz plus 0.8 Hz or plus 1.0 Hz)
So precise temperature and precise frequency cross their ways...
By the way, does anybody have op/serv manual for this thermometer?
Predrag Dukic
At 16:18 30.11.2008, you wrote:
Hello,
there's currently no easy way to convert a frequency into Volt, i.e.
other than by cryo Josephson junction array or realizing Ohm by a
Klitzing quantum hall effect device. Otherwise, FLUKE would have
implemented that already in their Calibrators/Standards. They
still rely
on Artefact Calibration, i.e. ovenized longterm stable Zener
References
and Reference Resistors.
The 5720A uses a stacked double Zener reference on a proprietary
hybrid
circuitry, giving 1-2 ppm/year stability, the 7001 and 732B use the
LTZ1000 (Zener above BE junction), as the 3458A, the 732A uses the
Motorola device (Zener below BE junction), and the elder 332D and
335D
use similar, but less longterm stable references.
The LM199, AD587 and I think also the Geller device may only be
used as
transfer standards, having poor longterm stabilities of 20ppm/yr.
or more.
Therefore, the LTZ1000 only may serve as a really affordable
standard,
i.e. below 8ppm longterm stability, for private use.
I was lucky to get some LTZ1000 samples, and used the standard
circuit
from the LT datasheet for creating a small PCB. I purchased
commercially
available wire wound resistors (TK 3, 25ppm/yr) for the 5 necessary
reference resistors and two OP07. Those resistors should give less
than
TK 1 and 1ppm/yr additional drifts.
Compared to my HP34401A, the circuitry showed quite good short term
stability below 1ppm, but shielding still has to be improved, as the
LTZ1000 circuit is susceptible to external EMC disturbances. This
Volt
reference then costs less than 100 Euros/Dollars in total.
I designed further circuitry (with TK 0.3 and TK 0.1 precision metal
foil resistors from Alpha and Vishay, chopper amp, precision switches
and Teflon insulated wires) to have the possibility for precision
transfers of the 7,2V reference voltage to 100mV, 1V, 10V, 100V,
1000V
level.
Only then, a Volt Standard is complete.
All this stuff will emulate or replace the commonly needed 732A
(ref),
720A (Kelvin Varley), 752A (Reference Divider) and 834B (Null
Detector).
Got no time yet to finish and improve the system, and to do the
repair
on an old 332B standard, but would like to share my knowledge, if
anyone's interested.
Frank Stellmach
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Hi,
Temperature is one quantity that is (or was) determined by physical
properties of substances.
I have a platinum resistance thermometer, but alone it is useless.
The simplest way of using it is to connect it in 4 wire mode to a HP
3468A multimeter,
and it measures the resistance with a resolution of about 1mK.
Connect it to another HP 3468A and it varies by less than 1mK.
So the HP 3468A measurement is robust.
Use a widely disseminated formula for the resistance of thermal pure
platinum
and it seems to measure temperature.
Construct an ice-point cell with a dewar flask, shaved ice, a
stirring rod and a syphon tube
and we seem to have calibration to better than 10mK.
I then built a hypsometer to boil water in.
The temperature of the steam did not shift 1mK in several hours.
But you have to use a barometer (Fortin pattern) to find the
atmospheric pressure,
correct for the density of mercury,
correct for the expansion of the scale,
get an estimate for local gravity from
the Geoid, apply an altitude correction.
The result was that a $10 platinum resistance thermometer seems to be
accurate to 1mK
but the ice-point calibration uncertainty may add plus or minus 5mK.
The big difficulty with temperature measurement is that you need
circulating thermostat
baths to immerse things in to compare temperatures to any accuracy.
You only need
one or two of those in your shack to have no room for your time
standards, voltage standards etc.
cheers, Neville Michie
On 01/12/2008, at 12:24 PM, Predrag Dukic wrote:
>
> Obsession for precision is the same whether one is after Hertz,
> Volts, or Degrees of Celsius (Or Fahrenheit).
>
> The methods and technology are similar...
>
> I am now trying to fix two HP2804A quarz thermometers, thet are
> giving some error codes, and do not work.
>
> More or less they are oscillators, and measure of temperature is
> measured by frequency shift between reference and external
> oscillator.
>
> Reference frequency is unusual 10.000.000,8 in one of them (marked
> exactly so) and 10.000.001 in the other.
>
> (Yes, yes, not a typo: it is 10MHz plus 0.8 Hz or plus 1.0 Hz)
>
> So precise temperature and precise frequency cross their ways...
>
>
> By the way, does anybody have op/serv manual for this thermometer?
>
>
> Predrag Dukic
>
>
>
>
>
>
> At 16:18 30.11.2008, you wrote:
>> Hello,
>>
>> there's currently no easy way to convert a frequency into Volt, i.e.
>> other than by cryo Josephson junction array or realizing Ohm by a
>> Klitzing quantum hall effect device. Otherwise, FLUKE would have
>> implemented that already in their Calibrators/Standards. They
>> still rely
>> on Artefact Calibration, i.e. ovenized longterm stable Zener
>> References
>> and Reference Resistors.
>>
>> The 5720A uses a stacked double Zener reference on a proprietary
>> hybrid
>> circuitry, giving 1-2 ppm/year stability, the 7001 and 732B use the
>> LTZ1000 (Zener above BE junction), as the 3458A, the 732A uses the
>> Motorola device (Zener below BE junction), and the elder 332D and
>> 335D
>> use similar, but less longterm stable references.
>> The LM199, AD587 and I think also the Geller device may only be
>> used as
>> transfer standards, having poor longterm stabilities of 20ppm/yr.
>> or more.
>>
>> Therefore, the LTZ1000 only may serve as a really affordable
>> standard,
>> i.e. below 8ppm longterm stability, for private use.
>>
>> I was lucky to get some LTZ1000 samples, and used the standard
>> circuit
>> from the LT datasheet for creating a small PCB. I purchased
>> commercially
>> available wire wound resistors (TK 3, 25ppm/yr) for the 5 necessary
>> reference resistors and two OP07. Those resistors should give less
>> than
>> TK 1 and 1ppm/yr additional drifts.
>>
>> Compared to my HP34401A, the circuitry showed quite good short term
>> stability below 1ppm, but shielding still has to be improved, as the
>> LTZ1000 circuit is susceptible to external EMC disturbances. This
>> Volt
>> reference then costs less than 100 Euros/Dollars in total.
>>
>> I designed further circuitry (with TK 0.3 and TK 0.1 precision metal
>> foil resistors from Alpha and Vishay, chopper amp, precision switches
>> and Teflon insulated wires) to have the possibility for precision
>> transfers of the 7,2V reference voltage to 100mV, 1V, 10V, 100V,
>> 1000V
>> level.
>> Only then, a Volt Standard is complete.
>>
>> All this stuff will emulate or replace the commonly needed 732A
>> (ref),
>> 720A (Kelvin Varley), 752A (Reference Divider) and 834B (Null
>> Detector).
>>
>> Got no time yet to finish and improve the system, and to do the
>> repair
>> on an old 332B standard, but would like to share my knowledge, if
>> anyone's interested.
>>
>> Frank Stellmach
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/
>> listinfo/time-nuts
>> and follow the instructions there.
>
>
> _______________________________________________
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> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/
> time-nuts
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