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NI 9401 specifications (I/O propagation delay)


I would like to use a CRIO module with eight NI 9401 cards. The application would have an internal trigger (let's say every 100 ms), and each output would have a delay generator with configured pulse delay and pulse width.


When browsing through the documentation of the NI9401 I get a bit puzzled. The specification say, if you use 8 channels, the maximal output frequency is 5 MHz. This is fine for me. What I do not like is the "I/O propagation delay" of 100 ns maximum.


Why 100 ns maximum? What does that mean? Will all channels on all cards be delayed for 100 ns? Or will card 1 have delay of 0 ns, and card 8 delay of 100 ns?

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From a pure spec perspective, I think your first interpretation is correct. That one card could have a delay of 0 ns since there's no minimum specified. In practice, I'd guess you'd see much less variation. Maybe 20 ns if you had cards from different batches running at different temperatures into different capacitive loads. Hopefully someone from NI can privately give you a lower end if it was a concern for you.


FYI, the 9402 gives a "typical" spec of 18ns

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