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Checking connectors for contamination

Posted: September 6th, 2018, 11:00 am
by TimOster
I'm trying to use a 6514 Electrometer to verify the assembly of a sample probe we build. The probe is used to measure 5G-Ohm samples during testing and maybe higher for our customers. We have been having trouble due possibly to contamination.

I've manually used the 6514 to measure both good and bad probes. The good probes over range (<210G) relatively quickly. The time I believe is the charging of the input capacitance (6514), and that which exists in the probe design. Bad probes take much longer, usually at least twice (> 2 mins) to show over range, or stop at some high resistance. 188G-Ohms for example.

The ones that eventually do over range, take longer I believe due to the extremely high resistance shorts...somewhere in the probe, constantly discharging the current that should be charging the capacitance.

Here is the problem. We don't want to do this manually, so I have created a .net class and written a test program to do this for us. What happens though it not the same as when I follow the exact steps manually. When I do it manually, it acts like I said above. Two mins or so to over range. But when I allow the program to run, I immediately see an over range.

I'm not sure if I'm supposed to post code here, so I'll save that for if anyone responds.

Basically I set to resistance, set autorange ON, limit the return to the reading, and then READ?. I am trying to do this in a loop every 10 seconds, but like I said, I immediately see over range. I do use the zeroing procedure and turn that off just before I ask for READ?.

Anyone?

Re: Checking connectors for contamination

Posted: September 9th, 2018, 1:29 pm
by Kiriakos
What you forgotten to mention this is if you are using SCPI mode ?
User Guide mentioning that full amount of control commands these are available at SCPI mode only.

Upload of latest firmware this it might also help.

Re: Checking connectors for contamination

Posted: September 10th, 2018, 9:34 am
by TimOster
You are correct. I forgot to mention that. Yes, I am using the SCPI commands to perform all setting changes and the readback the data.