PXIe-6363 DAQ AI max input voltage and potential damage

[wlmm10]

Hello,

The PXIe-6363 defines -10 to 10V maximum inputs on the input AI channels. Going above these voltages will rail the ADC output to 10V. I think the spec says the absolute max input is 11V.

The question I have is whether this absolute max comes into play only when the CH is activated and an ADC measurement is taken, e.g., in a voltage measurement task? If I connect a given AI channel to a higher voltage, e.g. 16V, but I do not actually start the task or obtain a sample on this AI channel, will this still possibly damage the channel? Or, when not sampling, is the AI in high impedance and the input is protected?

Thanks.

[BertMcMahan]

The specs here: https://www.ni.com/docs/en-US/bundle/pxie-6363-specs/page/specs.html

say this for overvoltage protection:

I would assume this means that it doesn't matter if you're taking a sample or not, it's got up to +/-25V for two pins while on, and +/-15V while off.

Either way, the AI channels are always high impedance (>10 GΩ) regardless of whether or not it's sampling.

[NIquist]

I suspect it is the opposite, and the card is more vulnerable to damage when NOT operating.  Note the specs for overvoltage protection and impedance:

I would avoid connecting larger than +/-11 VDC across any of the pins unless you get a clear OK from NI Support that you can safely do so.

EDIT: Bert beat me to it!