What is the recommended way to protect ai/ao lines when there is risk of seeing voltages as high as 60V?

[Sean.C]

Hello,

I am developing a test system for a board that has voltages as high as 60V.  While I am not trying to directly measure those levels, I do not want to damage my card if there is a short on the DUT.  What (if any) are the recommended methods of protecting the ai/ao lines from unintended application of such voltages? 

Thanks,

Sean

[Henrik_Volkers]

If your signal has a low impedance and is not sensitive to some more bias currents , you can use a current limiting resistor and additional clamping diodes.

Quick and dirty: 0-10V input range, 10V rail supplied by the DAQ, 10K current limiter and 1N4148s to supply and GND.

Depending on the input impedance of your DAQ this can have a serious influence. (and there are better solutions) . Just say your input impedance is only 100k and you use a 10k limiter, you are 9% off.