sheila.dwyer@LIGO.ORG - posted 11:49, Monday 07 December 2015 - last comment - 18:27, Tuesday 29 December 2015(24031)
PRMI to DRMI transitions
My previous entry about the PRMI branch in the ISC_LOCK guardian isn't as clear as it could be, so here is a newer version.
If you find that DRMI won't lock and seems to be missalinged (you see a lot of higher order modes on the AS camera, POP90 and POP18 flashes are low) you may want to lock PRMI to adjust alignment manually:
- with ISC_LOCK in the state LOCK_DRMI_1F (or any earlier states), request LOCK_PRMI
- Once PRMI is locked, manually adjust the alignment of BS and PRM to increase the POP18 and POP90 buildups. (POP18_I_NORM_MON around 50 counts and POP90_I_NORM_MON around 80 counts, should be stable).
- Once you are happy with the buildups, request DRMI_LOCKED. Either it will smoothly make the transition or it will break the PRMI lock and go back to trying to lock DRMI.
The transition from PRMI to DRMI only works sometimes, so this is probably best used only when the alignment is bad for now. (Its not a reliable way to speed up DRMI locking).
The above instructions have changed, only in that the name of the state to request is now PRMI_LOCKED:
If you find that DRMI won't lock and seems to be missalinged (you see a lot of higher order modes on the AS camera, POP90 and POP18 flashes are low) you may want to lock PRMI to adjust alignment manually:
The transition from PRMI to DRMI only works sometimes, so this is probably best used only when the alignment is bad for now. (Its not a reliable way to speed up DRMI locking).