[volt-nuts] DMM calibration

[Electronics and Books]

Specs for a 3478A


Brand HP Model 3478A Counts 303.099 TrueRMS X Display LCD  Year 1983 Range                     Stability [ppm] Low   High   Resolution      1y
DC Volt 30m  300  100n 60 AC Volt 300m 300  1u  2000 Max Frequency 300k Resistance 30  30M  100u 160 DC Current 300m 3  1u  1500 AC Current 300m 3  1u  7200 Interface GPIB Battery backup X 
If you do the adjustments with some hobby equipment wich an accuracy of say 20 to 30 ppm. Thats all within limits of this multimeter. You never see the difference.
In my opion, expensive adjustments and calibration for not so accurate equipment is a waste of money. Especialy when the calibration price exceeds the equipment price.
 



 
Regards


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________________________________
 From: "Marv @ Home" <marvin.gozum at comcast.net>
To: Discussion of precise voltage measurement <volt-nuts at febo.com>; Discussion of precise voltage measurement <volt-nuts at febo.com> 
Sent: Wednesday, August 7, 2013 6:53 PM
Subject: Re: [volt-nuts] DMM calibration
 

I don't know what logo cal is, but between Z540 and 17025 is a 
question of procedures and how they are done.
In metrology the procedures, and how strict they are, reduce the risk 
of uncertainty in the final measurement.  For example, some 
procedures in Z540 can be 'interpreted' where in 17025 is explicit, 
thus there is more room in Z540 for one lab to be worse than another, 
or vice versa, which defeats the purpose of standardization.  This 
'intepretation' is fairly reduced when the device is cal'd by an 
autocalibrator such for close case calibration DMMs, but becomes a 
big issue with any manual cal.

If these do not mean anything to you and you do not need the data for 
long term drift calculations, ISO 9001 is good to go.

IMHO the difference between all 3 is insignificant for 5.5 digit 
DMMs, except for one's need for data.


http://us.flukecal.com/literature/articles-and-education/temperature-calibration/papers-articles/comparison-ansincsl-z540-1?geoip=1

At 12:30 PM 8/7/2013, Joseph Gray wrote:
>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



Sincerely,



Marv
Philadelphia, PA 

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