Problem with using multiple piezo sensors with DAQ

[Zerroth]

Hi Sheela,

Sorry, have been studying for exams recently.

I took the ground connections off and the problem still persists.  I then swicthed the mode to NRSE, changed to the pins that the connection diagram showed. Still have the same problem.

I looked through the page you linked me to. I could not really find anything of use in it excpet for maybe this:

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Warning: Bias resistors must be provided when measuring floating signal sources in DIFF and NRSE configurations. Failure to do so will result in erratic or saturated (positive full-scale or negative full-scale) readings. 

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Maybe i should add some bias resistors? If so what value should i use?

Emile

[SheelaS · Accepted solution]

Emile,

Yes, you will need to use bias resisitors, and we recommend a value between 10kohm to 100kohm.

The following is a silghtly different problem, but it explains more about using bias resistors with piezoelectric sensors:

Why Am I Reading a Floating Voltage for My Piezoelectric?

All the best with your exmas 🙂

[Zerroth]

Thanks Sheela, that solved my problem. working perfectly now. 🙂

Just one more thing, is there any chance you can convert the windows_media VI posted by bnoronha 
in this thread so that i can open it in LabVIEW 8.5?

http://forums.ni.com/ni/board/message?board.id=170&message.id=386460#M386460

Thank you very much again,

Emile

Message Edited by Zerroth on 05-28-2009 12:05 PM