How do I determine what digital data was last outputted using regeneration?

[Tom_from_the_Lab]

Is there a way to determine the last digital data output if you are running a fast clock and using regeneration?  Right now I am using an unused digital channel to read the DO channel with the same clock I use for the other data capture. It works fine and I know the data I get is correct but there is something wrong with burning up a channel  for that. The data I am regenerating changes many times during the test so counting samples to determine where in the buffer I was would make my code a lot more complex and the chances of an error increase.

I have a mix of hardware I use from a cDAQ-9172, an M series USB box and a PXI-1033.

[ColeTrain · Accepted solution]

Hello Tom,

There is absolutely something wrong with having to use one of your channels to monitor what you are outputting, however that is the best that we can do right now.  The problem is, when you set a buffer up to output, the card just access that memory location to stream it back out.  This is to optomize speed and overall card design.  There is no return path on hardware to do what you are looking for and no software to interact directly with the buffer memory location.  

[ColeTrain]

For what it's worth, you can always file a product suggestion asking for this type of functionality within the card.  There are people way smarter than I am who have solved way more difficult tasks in the past and they may be able to do it again.  Visit here and click here:

[Tom_from_the_Lab]

Thanks for the input, I have submitted feedback on this. In the meantime I will continue to "double up" my digital ports when I need feedback.