sheila.dwyer@LIGO.ORG - posted 21:36, Wednesday 07 October 2015 - last comment - 22:03, Wednesday 07 October 2015(22322)
ALIGN_IFO guardian fix
Nutsinee started an inital alingment as part of recovering from the last lockloss. The INPUT align WFS loops failed for an unknown reason, and caused the X arm to drop lock with out offloading the WFS. At this point we noticed that the history in the suspension filters was not cleared in the down state of the ALIGN_IFO guardian, which caused the X arm to stay misalinged in this case. I've now added clear history for the filters.
We got to DC readout transition this time, but had similar difficulties to last night where the OMC locked on a wrong mode, switched to the dither alignment and became misaligned. I added a check on the DCPD sum in the OMC_LOCKED state, if the sum is below 14 mA it will give a notification and not move on the the dither aligment.
We went through a couple of rounds of turning of the OMC ASC, clearing the history, and turning it back on. I think this failed the first time because I didn't wait for the suspension to stop swinging before turning the ASC loops on again. The last time everything seemed fine, but we had been sitting at DC readout transition for a while. Like last night we lost the lock when we tried to transition.