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How to compare (MEMC) a value from reference instrument (34401 over GPIB) with manually entered value by keyboard?

I have to calibrate a power supply without interface, so I have to enter values from UUT's display by keyboad.

The problem is, the electronic load I use, has wide tolerances. If I send 1A to electronic load, real current will be about 1.04A.

So I have to measure the real current by reference instrument (34401A) and check, if displayed value on UUT's display (that I enter by keyboard) is in tolerance.

As far as I understood, MEMC compares measured value from an instrument to a (fixednominal, that is given by command line:

MEMC 1 1A 1%  ...will compare measured value with 1A (not with the real current of 1.04A).

Maybe I can write both register values MEMC uses (MEM1 and MEM ) before usage of MEMC FSC.

So I need to enter the value by keyboard manually into one of the registers, and I have no idea how to do this.

Someone please help me...

 

 

 

4 comments

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Krista E.

You can use an N in mod 4 and use the 34401 to get  your nominal value. It will go through and ask you to source the value from the UUT and then it will record the 34401 reading in MEM.

 

Then remember from MEMC help:

If the statement specifies a Nominal value, that value is used as the UUT Indicated value. 
The value of memory register MEM is used as the System Actual value. 
 
So you state your test value in the memc statement and the "real" value you are comparing it against is in MEM which is where you want it.
 
Try it.

Krista Erickson

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metcal user

Thank you, Krista.

It works:

------------------------------------------------------------------------------

9.008 IEEE [@HP60]CURR 1.0;:INPUT:STATE OFF

9.009 DISP Connect DMM and electronic load in series

9.009 DISP Use LO + I inputs on DMM

9.010 DISP Adjust power supply voltage to max

9.011 IEEE [@HP60]INPUT:STATE ON

9.012 34401   1   1.000A        N   2W

9.013 MATH MEM1 = MEM

9.014 MEMI Please enter current display from power supply: (Amps)

9.015 MEMCX     A      0.1U

--------------------------------------------------------------------------------------------

 

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Krista E.

Did you get the resolution issue worked out?  Yes - the way you have your nominal configured now:

1.000A  is correct

Versus  34401   1   1A         which is incorrect.

That goes for normal instrument fsc lines as well

so 

5520 1.000V 1% the value in the nominal column (1.000) must match your UUT (DUT) resolution.

Krista

 

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metcal user

Yes, thank you.

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