You would have to continuously monitor the user frame of interest, and compare the XYZWPR values to a previous version that you stored. Backgound logic sounds perfect for this, except you can't use Position Registers in BG Logic. To avoid PR's I would say get the values directly from the system variable ($MNUFRAME[1,*]) but I don't know of a way to get individual XYZWPR values directly into a register in TP. The system variable returns a position and, again, PR's are benched.
This would leave multitasking as the only option left I can think of, in which what you're trying to achieve is very easy to do in either TP or Karel, using the method I described above.
For your info, should you choose to use the multitasking option with Karel, it is possible to get the system's timestamp at the time a change is detected. It's probably pretty doable via TP too if there's some system variable with the timestamp you can access (which I'm pretty sure there should be).
