Synchronize cRIO and NI9239

[ghr1]

Hi all,

In my project try to send a predefined train of pulses (100kHz ) to a lab setup and measure the voltage response of the setup.

For this I use a cRIO with a FPGA, a NI9401 for sending the signal and a NI 9239 to measure the signal. On my FPGA I have one loop that reads bits from memory and outputs them via he NI9401 and one that samples one channel of the NI9239 and writes its value to a FIFO. The problem is, that signal generation and measurement are not in sync and what should be a sine with a period of 200 NI9239 samples turns out to be almost 201 samples long.

I think the OnboardClock FPGA I/O node of the NI9230 could be part of the solution, but I could not find any information about it. How does this I/O node work, can I use it, to change the clock rate of the 9239 "a ittle" so it syncs with the fpga clock?

Thanks!

ghr1