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Some old school instruments showing how it's done (HP 3325A and Fluke 8506a)
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joeqsmith:
Looks like pretty much every range is out for every function.  I checked the main supply and started to read the calibration adjustments section.   First step, install PN# MIS-7013K Bus Interconnect and Monitor Board.   They offered an extender board as well which would be handy about now.   

If I power up the meter, it defaults to DCV.   If I  then short all four connectors and select zero, it the Zero LED becomes active and it displays 0.000.   So it can hold within a 1mV for several minutes.  If I select the auto range, it looks like it will drift around by 5uV  (0.0050 -3) or so.  If I enable the average and filter, it seem to hold within 1uV (saw a 700nV).   

Having some software to store the min/max.... would also be helpful about now.  Does it have the ability to record basic metrics like this?

Did you write the software to run it through the software cal or is this something you found from Fluke?
SilverSolder:
Each range has its own zero - you need to set the range of interest manually, then set the zero. 

Min/Max is the PEAK button.  Press it, and it starts storing min/max from that point.

To see the values, press buttons RECALL-HI-PEAK and RECALL-LO-PEAK respectively.


The software cal is described in the manual, you don't need any additional software, just some reference voltages - the values are not important as long as you know what the values are!

The references just have to be anywhere from 60% of the top of the range or above, in order to do a calibration.   So if you have a 7.007365 volt reference, for example, you can use it directly to calibrate the 10V range without amplifying it up to 10V or anything like that....  pretty cool, as you can use the most stable "naked" LTZ1000 circuit (without 10 volt up-conversion) to calibrate with.

The calibration is done by throwing the CAL switch on the back (note: lots of dangers as protection circuits are disabled), then set a permanent zero and enter the reference voltage for each range.  RTFM!

Hardware cal is more work, but not too bad.

SilverSolder:

--- Quote from: guenthert on January 23, 2021, 07:05:54 pm ---     I bought a few older DMMs and all drifted less (or rather the accumulated drift was less) than the original specification would have allowed for (one HP 34401A even seems to have been "spot-on" in the 10DV range).  That might have been survivor's bias or an indication that the manufacturers specification are wider than necessary for instruments living an easy life.
     In any case, I haven't seen one, which drifted so far as yours.  I'd watch it for a while and observe the current drift, which might indicate some fault needing a repair before calibration.

--- End quote ---

All of the ones that I have were bought very cheaply - as junk, basically... -  and they were all still within spec, unless they were outright broken.  When fixed, they came back to spec.

joeqsmith:

--- Quote from: SilverSolder on January 23, 2021, 08:21:01 pm ---RTFM!

--- End quote ---

No problem.
SilverSolder:

--- Quote from: joeqsmith on January 23, 2021, 08:46:51 pm ---
--- Quote from: SilverSolder on January 23, 2021, 08:21:01 pm ---RTFM!

--- End quote ---

No problem.

--- End quote ---

I meant in the sense that it is possible to damage the meter in CAL mode, the manual explains how to avoid that.

I've never seen the printed version of the manual, BTW.  It does look rather intimidating on the picture...  I have it in PDF form (easier to search, and add notes).  Got it from Artek.



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