Displaying report 1-1 of 1.
Reports until 14:15, Friday 06 February 2015
H1 ISC
kiwamu.izumi@LIGO.ORG - posted 14:15, Friday 06 February 2015 (16523)
Green ASC camera servo issue fixed in Y arm

Ed, TJ, Kiwamu,

We fixed an issue associated with the camera servo in the green ASC loops. It is now functional as it should be.

When we were going through the initial alignment sequence this morning, we noticed that the Y arm green transmitted light decreased after the ASC loops were engaged. We figured out that this happened only when the DOF3 (which is the ITMY camera servo actuating on all three suspensions) was engaged. Adter some inspections, we found that the input of M0_LOCK_P(Y) were off on ETMY. Since the camera servo is the only one who actuates on ETM, the servo was introducing some funny imbalanced feedback into the cavity. Bad. We enabled them and confirmed that this fixed the issue.

Also, Alexa told us that she had a similar issue in the X arm green ASC yesterday and she had to switch off the camera servo. Checking M0_LOCK_P(Y) filters in ETMX, we found them also disabled. So we enabled them. We did not check whether this fixed the situation or not, but I believe that this fixed the issue in the X arm as well.

Displaying report 1-1 of 1.