Hi Everyone,
We are trying to trigger DAQmx functions using the FPGA on the same cRIO.
The idea, as it stands, is to use a NI 9042 in FPGA mode to export the trigger signal to the NI 9042 that is in Real-Time acquisition mode.
IIRC, there are ways to do this via the backplane or without any external wires, but team lead explicitly desires hardwiring externally like this.
An alternative I might try to pitch is to export via the 9042 into the PFI0 input.
NEVER THE LESS we're trying to capture as high resolution precision as possible... so I need to know more distinctly what is the minimum pulse width I need to generate on the FPGA for the DAQmx trigger function to detect it correctly.
An initial hunch is that the refresh rate will be limited by the real-time operating frequency. (somewhere in the ms range)
The nanosecond resolution is only for allowing us to precisely synchronize the trigger, I don't need to do this repeatedly such that we worry about data handling over multiple clock rates or anything super complicated like that.
From what I have looked up the specs on the NI 9042 say a propagation delay averaging ~20ns, but maxing up to 55ns. Between two of them that'd be ~40ns, 110ns... is that my answer sitting right in front of me (making the pulse width more than 110ns?) or do I have to account for the slow speed at which the real time system cycles?
Say the real-time system is running at 1khz... if a 125ns pulse comes, is it not going to be registered by the DAQmx trigger VI?
Thanks for your time