I-V measurement with E3631 and KE6485

[Code]

Hi,

I use an Agilent E3631a triple output power supply and Keithley 6485 picoammeter to obtain I-V curves. I use a for loop for this purpose. But I found a couple of problems with the measurement.

1. Voltage in E3631a keeps falling back 2% at each point. For example, even though I set it to 2.000V,it outputs 2.000 v first, then falls to 1.980 V. I don't know whether or not it is because of the for-loop.

2. Although I didn't set any delay time in voltage output, the sweep is not as fast as I expected. I am wondering whether or not there is a rate limiting step in VISA sessions.

This is my first labview program, so I want to post it here for critism and suggestions. Thank you. I use Labview 6.

[Emilie S.]

Hi Code:

I briefly looked at your code and it looks pretty good. It is hard to tell exactly what is going on without having the instruments though. I cannot tell why you would be getting the problems you are seeing but my suggestion would be to strip the code down and try one instrument at a time to see if you still get the same results.

Regards,

Emilie S.
Applications Engineer
National Instruments