One Shot Trailing Edge Applied to Xxx Input - Not Working?

[belias]

I've stared at this for 2 days now and I can't figure out what's going on.  I feel like I'm missing something obvious, so please be nice to me if it is...

This ladder logic comes from a task.  The top and bottom rungs work fine (the bottom run was actually just for my own testing).  The middle run that applies a trailing edge contact to the X38 input doesn't work.  Even when I provide a very slow (15 second) change to the X38 signal from ON to OFF, it still will not allow power flow.

As soon as I change the X38 to a C-bit and manually change it, it works fine.

Any idea what I'm missing?

[RBPLC]

Two things:
1) What command is on the output side of the rung?
2) What does your ENTASK look like for this Task?

[belias]

Sorry...the picture was apparently too large to show the whole thing (re-sized below).  The output is a simple STRPRINT command.

The ENTASK is set in the Main program:

ST1 ($On)  ---->   ENTASK (Interval 0)

And it's not like this is an intermittent thing...every single time, it works perfectly for a change in the C-bit, but not for a change in the actual input (X-bit).

[BobO]

I put this code in a task exactly as shown, and it worked as expected. Only thing I can think of is the input isn't really doing what you think. You could try forcing it on then off and see if that fires the logic.

[ADC Product Engineer]

Put a counter on the rung under this one and use the same logic to trigger it.  As Bob said, I would bet that it doesn't increment when you think it is.