Attempting to use change detection with USB6525 as generated event

[plyons.gks]

9.7 i think (already left work at this point)

thx

[plyons.gks]

I'm still stuck swinging on this stinking problem-

this is the error- clearly stating that no IO line has been chosen to detect changes on...

and this is the code shot of the property node that clearly wires in MIO1/port1/line0 as the line to detect rising edges on...

This same exact code works on another computer with the same LV/MAX versions and a USB6525... I'm now going to try switching the USB6363 to the other computer...

-pat

[John_P1 · Accepted solution]

Try doing it this way:

Best Regards,

[plyons.gks]

John-

thanks!, I was planning on posting up the solution after finally getting some help from a senior app engineer at NI (but im so busy I practically forgot about this post).  I also learned that the 6363 only allows for change detection on port 0 it seems...  

Thanks again

-pat

[John_P1]

You may configure non-buffered change detection on the other ports (like this):

Best Regards,

[plyons.gks]

nice!

thanks for the info!

what is the name of that vi you added there?

-pat

[John_P1]

DAQmx Configure Input Buffer.vi

Best Regards,

[Les__Bartel]

When running this sample, I get an error about not being able to unregister for events because a task is running. So I wire the error out from 'Clear Task' to the error in of 'Unregister...'. Now I get error 1, 'Input parameter is invalid'. I wired the 'Event Registration Refnum' wire through all of the cases, and still get error 1. How do I clean up properly?

[John_P1]

That is interesting...

Upon wiring the error cluster, I notice on my system that I do not receive the errors you are reporting whether I call unregister before or after stopping and clearing the task.  I am using LabVIEW 2011, DAQmx 9.7.5, and a USB-6251 (I happened to have this plugged in to my system).  I'll admit though that my use of the unregister without any error cluster was a bit lazy.

Error 1 is what you would get if you try to unregsiter an event which has already been unregistered--it sounds like perhaps the DAQmx Clear Task is unregistering the event for you, though I'm not positive and haven't heard of this before (what version of LabVIEW / DAQmx are you using?).  You didn't mention the other error code, but it sounds like the driver is telling you that the event can't be unregistered without first stopping the task (which is fair enough I suppose).

With this in mind, I would try calling unregister after stopping the task but before clearing it, something like this:

If this is indeed the way to explicitly unregister DAQmx events nowadays, then NI needs to update their shipping example:

https://decibel.ni.com/content/docs/DOC-25103

Best Regards,

[Les__Bartel]

This works. LV 2013 SP1, DAQmx 9.8.0.

Thanks and kudos 🙂