Physical Channel is empty

[ZhenhuanZhang]

Greeting! 

I'm using a NI-9411 on an CRIO-9045 to read rotation signal from an encoder.  The version of my software are : LabVIEW 2020, NI-DAQmx 20.0. LabVIEW Real-Time 20.0. 

I can see the NI-9411 module on MAX and I can run the test panel of NI-9411.  All works fine. 

The problem happens when I turn into programming in my LabVIEW.  I want to use NI-DAQmx to read counter channel of NI-9411, But the physical channels show EMPTY,  no channel shows up.  

Does anyone know how to solve this problem? Many thanks 

best 

[JensG69]

On which system do you try to run your DAQmx code? On your Windows host? Or on the cRIO-target.

You have to run your VIs on the compactRIO for that !

Regards, Jens

[FireFist-Redhawk]

Attach the VI you've put together so far.

[ZhenhuanZhang]

Hi Jen,

Thanks for your reply.  I have attached a figure of the project. I added the VI under my real-time target CRIO-9045.  When I open that VI for programing, I can not see the channel. 

[Bob_Schor]

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@ZhenhuanZhang wrote:

I have attached a figure of the project. I added the VI under my real-time target CRIO-9045.  When I open that VI for programing, I can not see the channel. 

You can see the Channel in MAX.  You cannot see the channel in the "VI under my real-time target CRIO-9045".  This suggests (to me) that your VI is the problem.  You failed to attach your VI, and it seems silly for me to try to "guess" what you did or didn't do in your code.

Please attach your VI (or VIs, or, best, the entire Project, compressed into a single .zip file).  That makes it much easier for us to see if there is a problem in your code.

Bob Schor

[ZhenhuanZhang]

I did not see the channel in my MAX last time, I only see my module NI9411 there. 

I found a possible reason. In the last time, I did not create a channel in MAX.  I thought if I can see my module 9411 in the MAX, then I can just read it with functions in my VI. But I think I'm wrong on that.  Today, I right clicked the NI9411 and chose " Create a task", Then I can see one channel appeared in tab of " Data neighborhood" .  Now if I add DAQ-Assistant in my VI, I can see the corresponding channel.  So I learn that I have to create a channel first, am I right? 

[santo_13]

So you're using DAQ Assistant?

NO - do not use DAQ Assistant, use the DAQmx drivers instead.

[Bob_Schor]

The Dreaded DAQ Assistant (DDA) is an extremely limited tool that can handle the most simple Data Acquisition Tasks.  It is built "on top of" DAQmx, an excellent (and easy-to-use) set of utilities that NI introduced about 15 years ago.  NI has an excellent set of DAQmx Tutorials and videos that you can find by searching the Web.  My favorite one is "Learn 10 Functions in NI DAQmx and Handle 80 Percent of Your Data Acquisition Applications".  But I suggest you find the other lessons in the DAQmx series and learn DAQmx.

Bob Schor