Keithley 6517 Zero Correction

[Yohan_B]

Hello guys,

I need to programm a VI so as to make multiple measurements including a low current measurement (pA) depending of the time. I'm using Keithley 6517 A/B electrometer. I want to do a zerocorrection to avoid any offset influence on my measurements.

After downloading the driver I tried to do something logic with the zerocorrect functions, but I can't get the REL sign on the display indicating that the correction is currently applied.

Then I've checked the 6517 manual to directly write SCPI commands.

That's what is written on it:

""""""

There are two methods to perform zero
correction. The first method is consistent with the way zero correction is performed from the
front panel. That is, zero correct is enabled, and then this command is used to enable zero correct. The following command sequence performs zero correction:
:SYSTem:ZCHeck ON ‘ Enable zero check
:SYSTem:ZCORrect ON ‘ Perform zero correction
The second method to perform zero correction is to first acquire the zero correct value, and then
use this command to enable zero correct. The zero correction is done with zero check disabled.
The following command sequence demonstrates this method.
:SYSTem:ZCHeck ON ‘ Enable zero check
:SYSTem:ZCORrect:ACQuire ‘ Acquire zero correct value
:SYSTem:ZCHeck OFF ‘ Disable zero check
:SYSTem:ZCORrect ON ‘ Perform zero correction

""""""

With the first method, it looks like it is working but then i can't read measurements with my programm, I think it is because I'm still in ZeroCheck mode. I tried adding a command for disabling zerocheck mode but then the REL message on the display goes away.

The second method seems logic but I have problems with the ACQ command. The Keithley displays Error 200: "Execution Error".

Currently, my measurements reading are made with these commands:

"""

:FORM:ELEM READ
:SENSE:FUNC 'CURR'
:DATA?

"""

Does anyone already faced that problem ? Is there a particular way to acquire these measurements in these conditions ? Does the 'REL' light mean an other thing that I didn't understand ?

Any help would be much appreciated.

Regards,

Yohan B