SIM FA moves are incomplete

[taldcroft]

The events archive for FA moves is incomplete. The code is using 3FAMOVE to find moves, but apparently it doesn't actually go to True for about half of moves, probably because they don't span a major frame. (And 3FAMOVE is reported once each major frame).

Likely need to use a new method of detecting diffs in 3FAPOS.

From Ken Gage on what the FOT does:

Focus moves are so short that the slow (major frame) telemetry often misses the flag.

I actually didn’t write the script that does that, but looking at it I find what I expected. The logic looks for either a MOVE flag or a change in position. That has on rare occasions caused a false reading. Specifically, at least once that I recall, the SIM Translation position shifted by 1 in between moves (probably not indicative of actual motion since the motor is locked when a move ends.)

Yes, we consider a (+) focus move to the 50 step overshoot position and the subsequent (–) move to the final position as two moves. Actually, a much more common problem I see with our script is conflating these two moves as it misses the intermediate position.