[volt-nuts] DMM calibration

[J. L. Trantham]

Joe,

Sorry to be so late answering this post but I'm 'tied up' right now and
can't get to all my data.

However, I have sent DMM's to Agilent (3458A), Fluke (289 and 8846A), and
Ametek - Solartron (7081).

Agilent was for their 'Agilent Cal' and it included 'As Found' and 'As Left'
data with 'adjustments' made for meters that were 'in cal' 'As Found'.

Fluke was for their Z540 cal.  On the 289, three types of data were offered,
'As Found', 'As Left', and 'As Found - As Left'.  Both my 289's were 'in
cal' and all I got back was 'As Found - As Left' and no adjustments were
made.  I can't recall what the 8846A was but I think it was for their Z540
cal, some measurements were out of cal, and adjustments were made.

Ametek gave 'As Found', 'As Left', and both repairs and adjustments were
made and included returning the replaced parts.

Comparing these meters to each other, using a Fluke 335A, Fluke 5450A, EDC
CR103J, and a Fluke 5100B, they are amazingly close.  Therefore, I feel that
these three companies provide a good service.

I had occasion (as a result of 'killing' the NVRAM by trying to read it
while still 'hot' from the removal process) to calibrate a 3458A using my
recently calibrated 7081.  I did not have a satisfactory AC source at the
time and used a 3326A, Fluke 335A, and some standard resistors.  I then sent
the 3458A to Agilent and the 'As Found' data was all 'in cal' except for two
of the 'mid-range' AC scales.

Now that I have a Fluke 5100B, I think I could do a good job calibrating any
meter by using my 3458A as a 'transfer standard'.

I have also calibrated a 3478A that I managed to lose the NVRAM data on and
it appears to be accurate as well.  I have not sent it to Agilent though I
have been thinking about doing that.

Good luck.

Joe

-----Original Message-----
From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
Behalf Of Joseph Gray
Sent: Wednesday, August 07, 2013 11:30 AM
To: Discussion of precise voltage measurement
Subject: [volt-nuts] DMM calibration

I just got the following quote for getting my HP 3478A calibrated.

35.00 for ISO 9001 no data
87.50 for Z540 with data and uncertainties
275.00 for 17025 with data, uncertainties and logo calibration.

I still didn't get any explaination as to exactly what the lab does for each
of these price points. When I asked about the "Level 4" listed next to the
meter, I was told that it is the difficulty level. Still not telling me
much. I have read the procedure in the HP service manual and it is very
easy. You set some volt, amp, ohm values on the standard, then push some
buttons on the meter.

I understand about getting data or not, it is the other aspects that I don't
understand. What is Z540, 17025 and "logo calibration"?


Joe Gray
W5JG
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