Products > Test Equipment
Some old school instruments showing how it's done (HP 3325A and Fluke 8506a)
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joeqsmith:
Sadly we lost power today long enough that the UPS cut out.  The Arb was brought up cold but still it appears it was going to be fairly drift free.   The 2mV of error could be the Arb, meter, terminator, all of the above.   Close enough.   


--- Quote from: SilverSolder on January 26, 2021, 05:25:23 pm ---You can get 1uV on both the 10V and 1V ranges.

It may perform slightly better on the 10V range?  Worth a comparison.  (Need to enable averaging to get to 7.5 digits on 10V)

--- End quote ---

After I noticed my manual was incorrect, I have not tried to enable the average again.   I just tried it out and it seems to work.   
joeqsmith:
My HP meter in red, the Fluke in white.  Both meters have been on for over 24 hours now.   The Fluke is set to average.   The top cover has yet to be installed.   Using my old 731B for a source. 

The software currently captures the data once every 5 seconds, so you are looking at about 1 hour of data.  Again, the Fluke was aligned using the HP.  The voltage standard could very well be tighter.   Ignore the absolute readings.
SilverSolder:

Interesting, are you seeing the "missing numbers" issue that @bdunham7 was talking about?
My GPIB setup is still down - when I get it back up and running, I'll try some logging to look for this issue specifically. 

As @bdunham7 said, it is hard to beat the metrology bang for the buck with these things.  But they can be hard to maintain if there are subtle problems unless you have another meter that is equally precise that you can compare it with.  One thing leads to another... !

The spec is nearly 2x wider on the 1V scale compared to 10V - probably due to the input attenuator?





guenthert:
     Even if the ADC would be unable to report some codes, the averaging surely will.  I can only assume that what @bdunham7 sees is coincidence.
joeqsmith:
Shown is about 4.5 hours.   Increasing the histogram's bin size to look at the missing codes,  the meter has not put out any 1s, 2s, 6s and 7's in the extended code.   We see something similar with the HP not showing 3s & 8's.

To test it out, I changed the voltage standard to delta E (uV resolution) and slowly adjusted the output voltage.  No missing codes.
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