failed to read PWM signal generated by LabVIEW and DAQmx

[Euni]

Dear all,

I'm a beginner of Labview and DAQmx. I create a simulated NI PCI-6225 device and a virtual channel by using DAQmx. I want to use the counter of PCI-6225 to generate PWM signal, then display the waveform of PWM signal. I generate the PWM signal according to an NI example "pulse width modulation using NI_DAQmx and Labview" (http://www.ni.com/tutorial/2991/en/ ).

This example can't display digital waveform, so I add a DAQmx read module. Then there is an error " Error -200460. Read failed, because there are no channels in this task from which data can be read. Task Name: _unnamedTask<21>".

I tried different methods to modify the error, like add while loop, change sample rate, and so on. But, these don't work.

The problem may be simple, but because I'm a beginner, it's confusing to me. I've uploaded my .vi file. Hope to get help from you. Thanks a lot.

[ErikaB]

Hi Euni,

Does this device work in the original example? Did you only start to get the error when you used your modified code? Are you able to create a different task -- as in, is this isolated to just the Counter Output from the card?

Hope this gets you moving in the right direction!