Can someone tell me what the "Match Transition Array" option does and why it is NOT shown in the help file???

[balmerjd]

So I've been doing some really screwy stuff lately to make scrolling windows and things in a data recording application and in one of my sub-VIs I end up using the "DWDT Get Waveform Time Array" function.  No big deal, but with all of the VIs I use I like to be able to know what all the inputs are and how to use them.  So I check out the context help and I get shown this:

Great!  Just what I wanted to see.  Ok so there's in, out, blah, blah,....  What's this "Match Transition Array???  So I click on Detailed help and get this....

Um.... Yeah.... Where's the Match Transition Array input and its description of what the heck it does???

Anyone have any ideas???

[JÞB · Accepted solution]

If Match Transitions is true AND There are Transitions in the DWfm the Time array returned will be the time of the transitions otherwise the  Timestamp Array will contain the sample times. NOTE From inspection of the BD in LabVIEW 2016

Rolling my 8-Ball (guessing) as to why it is undocumented.  The behavior that reverts the array output to time of samples with no transitions in the input waveform is debatable.  I could argue either way whether in the case where there are no transitions that the current behavior is prefered or that the Timestamp array should be empty.  Undocumented behavior is subject to change.

[balmerjd]

Thanks for the info.  I suppose short of someone from NI commenting as to why the feature is undocumented there really isn't a good explanation (though yours is pretty reasonable).

Either way though, that's actually a pretty useful feature for the right application.  That actually makes me even more puzzled as to why this isn't documented regardless of whether the current behavior in the case of an empty array is "correct" or not.

But again, thanks for the assist!

[JÞB]

Testing for empty transition array can be done a lot easier.  Argument for current behavior.  You have the correct argument against.

[the_mitten]

Hi balmerjd,

Thanks for pointing this out, and thanks Jeff for the answer! I've done some digging here, and can't find any obvious reason on our end why this is not documented. I'll file a request to ensure that this terminal is documented in the future.

Regards,