filter SC-2345: signal drift issues

[swoodman1]

Hello all,

Our lab has a NI filter SC-2345 (Signal Conditioning Connector Block) to filter out noise from motion sensors used in a MRI console.  We also use LabView to gather this data in our computer.  The problem is that when we set up our equipment (serial cables with motion sensor at end) the signal seems cleaner, but appears to drift- eventually going out of our field of view.  This (floating) signal is drifting out of range over time. We are thinking it might be an issue with the grounding?  Does anyone know how to properly ground this device?  What could fix this problem?  Would adding resistors help? and are there fixes without adding resistors?

Any help or advice is much appreciated.

Thank you!!

Sandra

[Marcus_M]

Hello Sandra,

This is Marcus in Applications Engineering.  Thank you for your post.  I have attached a document which I think will be helpful.  It has procedures for wiring your analog signals and also has a section on noise and floating signals which I believe will be relevant to your case.  

Please let me know if you are still having issues and I will do my best to assist you.

http://zone.ni.com/devzone/cda/tut/p/id/3344#toc2

Regards, 

Marcus