ESD damaging NI 9234 module

[charliep]

Hi,

I'm using a NI 9234 DSA module with a triaxial accelerometer (IEPE powered, AC coupled). The system works fine for a while, and then one of the channels goes out - with lots of noise riding on almost no signal.

When I replace the module with a new one ($1800!), the system works fine again for a day or two, and then a channel goes out again. It is not always the same channel.

The system has been working fine for several years without a NI 9234 problem, but now, I have had three modules fail in the last week and my system is down with no more spares.

Any ideas as to wht could be causing this damage? Is it possible that it is ESD when the operator picks up the accelrometer to place it on the DUT?

Thanks and regards,

Charlie Allan

Novatorque

[Henrik_Volkers]

So, what has changed?

New/additional/changed installation?

Broken ground/shield cable?

I would hook up a scope at the inputs and monitor various differential voltages.

The accelerometer commonly are used in a setup ..  is that stationary (machine monitoring) or changing (test/cal facility) ?  

If you power up/down  or connect/disconnect  items, maybe spikes are generated....   

[charliep]

Hi Henrik,

I spoke with NI about this problem, and they thought that it might be the DAQ chassis causing the 9234's to fry. So I changed the chassis, and have had no other 9234 failures in one week:)

Thank you for your quick response.

Charlie

[Henrik_Volkers]

Thank you for the feedback.  Seems that you found  the reason. Migth help others in the future.