Electronic – How to measure resistance across a capacitive load using an Agilent 34410A in GPIB mode

multimeter

I'm trying to measure resistance across two test points in a circuit that has an overall capacitive load. This is for a very specific application and it is to ensure there are no shorts in the circuit. When I use my Agilent 34410A manually (continuous triggering) I have to wait for a few seconds for the capacitors to charge up and then I get a high resistance value as expected, showing there are no shorts. But I need to do the same thing using GPIB. The trouble is, when I use the GPIB commands such as "MEAS:RES?" or "CONF:RES; READ?" or "CONF:RES; INIT?; FETCH?", they all take a quick snapshot of the resistance and don't provide the capacitors enough time to charge and so they show a very low resistance reading. Is there a way I can mimic the continuous trigger reading that I can do manually, but using the GPIB mode?

Best Answer

OK, I got it to work. This procedure will do:

CONF:RES
INIT
<place code here to wait a little bit>
INIT
FETCH?

Basically, "CONF:RES" will place the meter in resistance measurement mode. The, first "INIT" will apply voltage and measure resistance and will place the first measurement in memory. At this point this first measurement is accessible via "FETCH?" but this is not what I want (this is the low ohmic value before the caps are charged). After a few seconds of waiting, a second "INIT" will take another measurement of the resistance while not ceasing to apply voltage between the two INITs so the caps will be charging all along. The "FETCH?" will then return the final resistance value at equilibrium when all the caps are charged.

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