For questions like this, I always RTFM...... Read The Fantastic Manual.....
Page 30 of Doc #1465, OptoMMP Protocol Guide. (http://www.opto22.com/documents/1465_OptoMMP_Protocol_Guide.pdf)
I will quote it here.....
"(digital and analog points)—A watchdog monitors communication on the OptoMMP port (port 2001, unless you have changed it). If nothing accesses the port for the length of time set in the watchdog, the I/O unit automatically sets designated digital and analog I/O points to the values you have determined."
To me, that is pretty cut and dry. ANY communications on port 2001 will reset the watchdog timer. It does not matter if it PAC Display, PAC Control or a .NET program. If there is activity on port 2001 it will reset the watchdog timer.
The SNAP-PAC or SNAP-Brain does not know what is talking to it on that port, there are no special 'signatures' that identify the source of traffic on that port, it just knows if it is hearing traffic, don't fire the watchdog.
Just a personal note, I really like that Doc 1465 and have read it end to end several times over the years. It's a great way to get to know your Opto.