Keithley 6517Continuous Voltage Read

[Akello]

Hello,

I'm working with a Keithley 6517A Electrometer/High Resistance Meter. I've downloaded the driver (http://sine.ni.com/apps/utf8/niid_web_display.model_page?p_model_id=2978) and successfully modified the example file to monitor for X seconds and write into a spreadsheet file. Now I'd like to do some more modification so I can get continuous readings written into a spreadhseet.

I started out with a VI that Dennis_Knutson posted here (http://forums.ni.com/t5/Instrument-Control-GPIB-Serial/Continuous-Measurement-with-Keithley-6517-ele... It works great but is a bit over my head and I had trouble modifying it to my needs beyond the continuous read. I then tried ibecerra's VI posted here (forums.ni.com/t5/Instrument-Control-GPIB-Serial/measure-current-continuously-with-Keithley-6517-electrometer/td-p/684028) and had more success with modification. I got rid of the Zero Switch and changed the current to voltage. Everything works when the VI runs but the timing is way off. I set the timer value to .001 but get around 100 readings for several minutes of operations (should be 1000 per minute). Further, when I look at the instrument's front panel, I see the voltage reading switching on and off every time unlike in Dennis_Knutson's vi where it stays on. 

I suspect the problem lies with the device being polled for a single read each time but can't figure out a way around that to a truely continuous reading. Multiple Readings seems like it wouldn't work here but I don't know what I can do for the single reading besides remove the Zero Check which I did. I tried finding the difference in the working continuous read VI but, as I mentioned, it's a bit over my head and I can't isolate it.

Hope to hear back from you, any advice is greatly appreciated.

Thanks,

Yusif Nurizade

[ConnorM]

Yusif,

The VI that Dennis_Knutson wrote looks like it will work for you, and all we need to do is add streaming the readings to disk. Correct? For saving to disk as the program runs, check out the example TDMS-Write data (time domain).vi. It may be under a different name depending on the version of LabVIEW you have. 

-Connor

[Akello]

Connor,

Thank you for the reply.

You are right; Dennis_Knutson's VI works perfectly. At this point, however, my skills are not so sharp as to allow me to easily modify the stucture of his VI. I've acheived a similar functionality off the VI that I made off the example with the exeption of the panel seemingly switching off an on (comes back to 0 for every measurement) as opposed to running continuously as in his.

I am hoping to get some advice as to what has to be changed in my VI to achieve that continuous run. I thought it had to do with the Zero Check but, while that has improved things, that was not the fix. 

Thanks again,

Yusif Nurizade

[ConnorM]

Can you also post your modification to the single read vi. We cannot see what changes you made to the shipping example.

[Akello]

Connor,

My apologies, here it is.

Best,

Yusif Nurizade

[ConnorM]

Yusif,

The reason why you are seeing it reset to 0 every loop is because you redo the configurations every time. Notices in the other example we only set the configurations once and then just collect data. I added file streaming to Dennis’s example to show what I was talking about.

Connor