Hello,
I am working on a project that requires two digital waveform outputs at different frequencies. Wave 1's frequency is about 1 kHz and is modulated on and off at a rate that will change during the execution of the program. Wave 2 goes from 1 kHz to about 6 kHz while needing to be fairly accurate to one tenth of a Hertz.
I initially tried to handle the simultaneous waveform output at different frequencies using one daqmx task on a single 9477 in a cdaq-9174 chassis. As far as I know, the best way to get accurate frequency in a waveform output is to set the sample rate to 2 times the frequency of the wave that is being generated and generate a waveform that switches at every clock cycle. This works fine when dealing with one wave, however I was unable to get the frequency of the modulated waveform (wave 1) to remain constant when the frequency of wave 2 changed or vice versa.
I have a few other modules lying around (another 9477, 9403, and 9476) and I thought that I would try running another task on a separate module. I end up receiving Error -50103 if I add any of those modules to my cdaq chassis and run one of the waveforms from a task set to run on the extra module. Is there any way around this error? I assume it to be caused by running two digital output tasks on the cdaq-9174 at the same time, but it would seem to me that with an extra module this would not be a problem.
How can I have two digital waveform outputs, running at the same time, maintain their frequency independent from changes to frequency of sample clock rate of each other. Also, because wave 1 is turned on and off at a set frequency, I use it to set the number of samples to write when writing an array of waveforms to the module (when generating both waveforms on the same module).
I'm sorry if the explanation was hard to understand. I have attached an example of the 50103 error being thrown. This is not really a part of my overall project but it is the simplest way to reproduce the error.
Thanks