simulate signal in daqmx settings

[sj367]

Hi,

I am trying to simulate a sine wave from a DAQ and reacquire the signal from the same daq, as well as from another daq. I am not able to get the sine signal generator and the daq assistant to function correctly. For example, if I set the sine wave to output at 10hz, it appears to function correctly. If I were to change this to 7 Hz, it outputs a very strange signal. I tested the output of the DAQ on an oscilloscope and it looks the same as the acquired input to the ADC. Clearly I am doing something incorrect and would appreciate advice on how to resolve this.

I am attaching the VI, as well as the output graphs for two sine waves at different frequencies.

Thank you

[sj367]

Also, I am using USB X 6356

[Tarek]

Hi sj,

Took a look at your code. It seems that the Simulate Signal VI is not generating samples as fast as the DAQ Assistant VI is writing to the channel, so the latter is writing the sampels in the buffer more than once, which is resulting in a strange signal.

Try to set the number of samples in both VIs to be equal to, let's say, 2000 and run it. (at the rate of 10kHz, 2000 points would cover one period of the 5Hz signal)

Hope this helps.