An update on my 'new' (formerly Stan's 'old') 7081.

It arrived in good condition and seems to work OK.  Just beginning to get
familiar with it this weekend.  The 'knobology' is certainly completely
different from any other DMM I have ever used.  I finally figured out how to
make a measurement.  I guess I am not familiar with the 'high-end' meters.

The connectors for the test leads are, indeed, the correct connectors.  I
plan on ordering a couple more along with a spare panel receptacle in case I
encounter any 'contact' issues.  Also, the 'AUXILIARY SOCKET' is not
installed on this meter and I will order that and a connector as well.  Does
anyone know what purpose it serves?  I looked at the schematics in the
manual and it shows how it is connected.  Does anyone have a picture of the
connection to the PCB?  Do two of the wires use connectors that slide over
pins at 'TL1' and 'TL2'?  The other two wires connect to the 'RATIO
REFERENCE INPUT' and 'REAR INPUT' connectors.

The CAL key Jerry sent me works!  Interestingly, in the 'NORMAL' position,
the switch is 'closed' and in the 'CAL' position, the switch is 'open'.  So,
minus a key, just unplug the connector for the cable from the switch to the
circuit board and you are now in 'CAL' mode.

I have made up one test lead, the 'two terminal input lead' using 10KV
Pomona silicone rubber test lead wire, connecting the red wire to pins 4 and
5 and the black wire to pins 1, 2, and 3 at the connector.  I am not
entirely sure that is how it should have been done but it seems to work.
Now waiting on some cable banana plugs to mate with the probes.  Forgot to
order those with the probes.  Next will come the Kelvin leads and the 3 wire
lead.

Also need to come up with a solution for the RS232 terminal program issue so
I can communicate with it and 'DUMP' the CAL Constants.  I am very weak on
the computer issues so that promises to be a learning experience as well.

Then to figure out how accurate it is.  Any 'volt-nuts' in the Panama City,
FL, area?  Would love to compare readings with an HP 3458A or participate in
any 'traveling standard' that might come to pass.

Thanks for all the help.

Joe

I am planning to make a set of Kelvin cables for my new meter and would like
to use a 4 conductor, shielded cable with 18 ga stranded wires.  I have
found several possible sources but do not want to buy 1000 feet.  Any
suggestions for a source for 10 feet or so of suitable cable for this
application?

Thanks in advance.

Joe

Hi Joe,
I strongly recommend VanDamme cables. Very high quality, flexible, huge range, don't have to buy a reel, resonably priced and a range of colours. I understand that the NPL use it in their calibration labs. I'd suggest "starquad" microphone cable for minimum noise pickup.
http://www.vdctrading.com

Regards,
Robert.

--- On Thu, 1/9/11, J. L. Trantham jltran@att.net wrote:

From: J. L. Trantham jltran@att.net
Subject: Re: [volt-nuts] Solartron 7081 - Any suggestions for cable for Kelvin Clips
To: "Discussion of precise voltage measurement" volt-nuts@febo.com
Date: Thursday, 1 September, 2011, 4:22

I am planning to make a set of Kelvin cables for my new meter and would like
to use a 4 conductor, shielded cable with 18 ga stranded wires.  I have
found several possible sources but do not want to buy 1000 feet.  Any
suggestions for a source for 10 feet or so of suitable cable for this
application?

Thanks in advance.

Joe

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 have been testing my 'new' 7081 and suspect I have arrived at the 'usual'
cross roads of what to believe.

I have two Fluke 731B's that I got from 'the site'.  I replaced the battery
packs in months past and have left both on for the past 3 or 4 days along
with the 7081 and other meters, an HP 3478A and an HP 3457A, as well as a
Fluke 335A voltage standard set to 10.000000 volts, all from 'the site'.

Regarding the 731B's, one is a 'white' face and the other is a 'black' face
and both are set to 10V.

I left the 7081 connected to the 'black' face 731B, set to 7 X 9 (3.2s) in
'TRACK', and walked in to the shop to find it reading 10.000000.  When
connected to the 'white' face 731B, it reads 9.999898 and, when connected to
the 335A, it reads 10.000392.

The 3478A reads 10.0001, 10.0000, and 10.0005, respectively.  The 3457A
reads 10.0001, 10.0000, and 10.0005, respectively.

Soooooooo, what, if any, conclusions are reachable?  I am tempted to believe
that the 'black' face 731B and the 7081 are correct.  What are the odds?

Thanks in advance.

Joe

Hi Joe,

To display one more digit of resolution on your HP 3457A, do this:

1. Press "DIGITS DISP"
2. Press "6"
3. Press "ENT"

For a more quiet reading, do this:

1. Press "NPLC"
2. Press "100"
3. Press "ENT"

After several hours warm-up, be sure to run "ACAL ALL".

I'm guessing your HP 3457A might typically be within 10ppm at 10Vdc.
Possibly within 5ppm but not likely better than that due to drift and
stability issues.

For example, my 3457A has drifted 5ppm since last "CAL 10"  (5 years ago).

Of course in your case there's the uncertainty of not knowing when your
instruments were last cal'd by previous owners.

It sounds like you're a prime candidate to participate in a VDC round-robin,
as the other fellows are now discussing and proposing?

Cheers!
Greg

----- Original Message -----
From: "J. L. Trantham" jltran@att.net
To: "Discussion of precise voltage measurement" volt-nuts@febo.com
Sent: Friday, September 02, 2011 5:02 PM
Subject: [volt-nuts] Solartron 7081, other meters, and some voltage
standards

I have been testing my 'new' 7081 and suspect I have arrived at the 'usual'
cross roads of what to believe.

I have two Fluke 731B's that I got from 'the site'.  I replaced the battery
packs in months past and have left both on for the past 3 or 4 days along
with the 7081 and other meters, an HP 3478A and an HP 3457A, as well as a
Fluke 335A voltage standard set to 10.000000 volts, all from 'the site'.

Regarding the 731B's, one is a 'white' face and the other is a 'black' face
and both are set to 10V.

I left the 7081 connected to the 'black' face 731B, set to 7 X 9 (3.2s) in
'TRACK', and walked in to the shop to find it reading 10.000000.  When
connected to the 'white' face 731B, it reads 9.999898 and, when connected to
the 335A, it reads 10.000392.

The 3478A reads 10.0001, 10.0000, and 10.0005, respectively.  The 3457A
reads 10.0001, 10.0000, and 10.0005, respectively.

Soooooooo, what, if any, conclusions are reachable?  I am tempted to believe
that the 'black' face 731B and the 7081 are correct.  What are the odds?

Thanks in advance.

Joe

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.

Hi again Joe,

Disclaimer (to my last post):
Although my old (aged) 3457A drifted only 5ppm in the last 5 years - and
your particular 3457A might do as well - we have no "guarantee" of that
based on HP's original 3457A specs. For example your 3457A could be off 50
ppm in 1 year yet still be in tolerance. I've not observed that much drift
in a 3457A - but just pointing this out so as to cover all bases and
possibilities.

...All of which brings us back to the usefulness of the proposed DCV
round-robin proposals being discussed.

Best,
Greg