How to connect HV probe to NI-DAQ?

[xwang0329]

I'm an electrochemist educated from Chemistry background and have to build instrument for research. When no one around me is a electrical engineer or instrumentation expert, I do things naively. God bless, I am still alive.

[xwang0329]

That's right point. I once had the computer black screen during measurement. I think it's safer to use an Oscilloscope digitizer and NI-scope software to do this job.

[Henrik_Volkers]

I don't know your HV source .. please make shure not to kill yourself.

What model of probe do you use?

Usually the probes ecxpect a 1 MOhm and some pF as input impedance  (and need some individual adjustment to that capacity, however depends on your dynamic range ... how fast the voltage is changing) and depending of type a serious grounding is improtant.

The 6009 has an input impedance ot 144 kOhm and unknown capacity, and as far as I know a 1.25V bias , so it need a low impedance source .....     I wouldn't expect it to work properly.

[JÞB]

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@xwang0329 wrote:

I'm an electrochemist educated from Chemistry background and have to build instrument for research. When no one around me is a electrical engineer or instrumentation expert, I do things naively. God bless, I am still alive.

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Make sure to post back with ways you found to learn more about taking these measurements safely.  (Unless Darwin's theories become applicable,  of course )

[xwang0329]

Thank you for your reply! Greetings from Texas, USA. You’re right that USB-6009 doesn’t work well for this job. The negative voltage beyond -200V can’t be measured as DC. I eventually switched to an oscilloscope digitizer card and it worked well. It has input impedance of 1MOhm.