well........ if your brave enough.....
You could set up a "Timer" in your PLC script that watches for a User Made LED on your machines run screen.
Then in your M2 or M30 or what ever... when that script runs have it "Turn On" that User LED.
the PLC script will be watching for it to turn on, when it does you could have a wxTimer run for what ever amount of time (if any at all),
that when it timed out, it would Turn OFF your Output that enables your Geckos....
There could be many ways to skin this cat.
Scott