Register Change Detection Event on USB-6221

[dacad]

Hi All,

I am using the Change Detection Event to trigger a User Event.  Essentially, capturing a user controlled digitial input change to trigger another command.  This was working pertty good on my prototype but is now not working on my final configuration.

I am using a USB-6221 and I have received and error about not using a DIO channel that supports Change Detection.  I did rearrange my DIO assignments between the prototype and final version and was trying to use DIO P1.2  I made no other changes.

I looked in the manual for this board and it does not make any indication on limitations on what DIO's can be used for Change Detection or not.   Did I miss something in the manual or is this information listed somewhere else?

Or does someone just inherently know which channels can be used specifically for Change Detection Events.

Thanks

Doug

[John_P1]

Hi Doug,

Change detection is only available on port 0 of our current Multifunction Devices (shown on page 6-8 of the M Series User Manual).  Is it possible for you to go back to P0?

Best Regards,

[dacad]

Thanks for the feedback on this.   I can change back to port 0 but wanted to make sure it was a hardware limitation vs. some other issue.

I had already looked at that section of the manual though and after looking again, can not find any mention of this feature being limited to port 0.

The text saying specifically   "..... on each DIO line."  The diagram listing P0.0 ..... P0.31 appears to be an example as opposed to a stated limitation.

Will know for next time though.

Thanks

Doug

[John_P1]

Hi Doug,

I agree that the manual does not exlpicitly state that change detection can only be done on port 0 of your M Series card.  The diagram does show the P0 lines as the change detection circuitry but it doesn't clearly state that this is the only port that the circuitry is present on (which it is).

There are a few scattered references that mention that change detection can only be performed on port 0 (e.g. Which NI DIO Devices Support Change Detection?), but it would be nice to make the manual more clear.  I'll look into getting this implemented on our end, thanks for bringing it to our attention!

Best Regards,