Output frequency to a port mentioned in MAX

Question

Hi,
I am trying to output ca. 100 KHz on a PIF port using NI 6351. I used example from NI example bank and it's working fine with the following code.
DAQmxErrChk (DAQmxCreateTask("",&gTaskHandle));
DAQmxErrChk (DAQmxCreateCOPulseChanFreq(gTaskHandle, aChannel, aVirtualAddress, DAQmx_Val_Hz, aIdle, 0.0, aFreq, aDuty));
DAQmxErrChk (DAQmxCfgImplicitTiming(gTaskHandle, DAQmx_Val_ContSamps, 1000));
 In the above example, I am creating a COPulseChannel and aChannel represents its physical address (for e.g. Dev1/ctr2) and aVirtualAddress is the one which I can assign to this physical address for future use.
My question is:
How can I create a virtual channel in MAX and use its name here with a name say "myFrequencyChannel" and then write a function to output Frequency to this channel?
Motivation:
This was possible till now for all channels like AI/AO/DI/DO, where I defined all channels with virtual names in MAX and then simply performed tasks by forwarding their names (only) to my functions. So the user need not remember always physical channel but just virtual channel names.
Thanks in advance.
Regards
RB
Solved!
Go to Solution.

Answer 1

Hi,
I think I misunderstood your questions. I though you wanted to import a Virtual Channel from MAX. 
 As background info: You use the function DAQmxAddGlobalChansToTask when you want to import a global virtual channel from max and DAQmxCreateCOPulseChanFreq when you want to confugure it all programmatically. aVirtualChannel in your example in the name you want to give to the created channel. According to the help, you can also let this field empty. 
Long story short, you use either DAQmxAddGlobalChansToTask to import a global channel from MAX or  DAQmxCreateCOPulseChanFreq to document your task programmaticaly. Then you can start your task using.
DAQmxStartTask (gTaskHandle);
 I still have doubt concerning my understanding of your question. Please let me know if that is answering it.
Best regards 
Florian Abry
Application Engineer Group Leader
NI Germany