The error message in the screenshot above has several possible reasons, the one applicable here is "Sample timing type is something other than On Demand". The root cause for this issue is a conflicting setting of the Simulate Arbitrary Signal node and the DAQ Assistant's Timing Settings: As an example, the former could have been set to generate one sample per loop iteration whereas the DAQ Assistant could have been set to write 1000 samples per iteration.
There are two possible solutions to this disparity:
- Set the Simulate Arbitrary Signal node to output the Entire Signal each iteration and configure the DAQ Assistant to N Samples. Remove the loop. Make sure the Samples to write value in DAQ Assistant is the same or less than Number of points defined in the Signal Simulator. This way the complete signal is generated at once, transferred to the USB-6211 which then outputs it automatically.
- Leave the Simulate Arbitrary Signal node Signal Generation setting as One Point per iteration, but set the DAQ Assistant to 1 Sample (On Demand). Add code into the while loop to handle the needed timing.