How do I use the virtual channels, created in MAX, in my LabWindows/CVI application?

[DanielH]

I'm running Measurment Studio 6.0 and NIDAQ 7. I have installed the NiDAQ 6533 card properly and created a number of virtual channels with MAX. How do I access these virtual channels in my LabWindows/CVI application? I have tried saving the channel setup as a traditional NIDAQ configuration, but how do I include this setup in my project in LabWindows?
/Daniel

[Wendy L]

Hello Daniel,

You can access virtual channels in CVI through the Easy I/O for DAQ functions. The attached KnowledgeBase goes into further detail.


Thanks.

[DanielH]

Thanks,
Will this only work for easy I/O? I would like to send patterns to my virtual channels, is that possible with easy I/O or will I need to configure channels within the application manually in that case?

[Wendy L]

Hello Daniel,

You can use the Easy/IO functions to write patterns to your analog output channels.

In particular, if you are using analog output, there are functions to create or read in a waveform and write it out to a virtual channel.

On the other hand, you're not going to be able to do patterned digital output using the Easy/IO functions, since you're going to have to use some of the more advanced DIO C function calls that require physical channels instead of virtual channels.

On the other hand, if you use the DAQmx driver, and create DAQmx tasks, you will be able to write analog and digital patterns to your board via CVI. The DAQmx Library allows you to load tasks previously created in Measurement and Automation Explorer. Also, there are example to do patterned digital output and waveform analog output in the CVI example finder.

If you are using a board that is not supported in DAQmx or if you have pre-existing code that cannot be ported to DAQmx, then staying with Traditional DAQ may be the best solution. Otherwise I would suggest taking a look at the DAQmx examples and see if those will work for you.


Thanks.