cheryl.vorvick@LIGO.ORG - posted 10:16, Wednesday 20 April 2016 - last comment - 12:30, Wednesday 20 April 2016(26685)
IM1, IM2, and IM3 now have a notification in DIAG_MAIN when alignment has shifted
The IM alignment shifts have caused locking issues, and so I asked TJ to add an alignment notification for IM1, IM2, and IM3 in DIAG_MAIN.
I've set the notification levels at:
- IM1 pitch and yaw, +/-5urad
- IM2 pitch and yaw, +/-10urad
- IM3 pitch and yaw, +/-10urad
These levels reflect roughly twice the drift in a recent 60 day trend.
Nominal alignment values in the notifications are:
- IM1 p: 187
- IM1 y: 1118
- IM2 p: 603
- IM2 y: -205
- IM3 p: 1965
- IM3 y: -79
IM3 yaw nominal value may need to be updated in about a month, since it has a sustained downward drift that was present through O1 and continues.
- TJ, Cheryl
To clarify:
Limits on alignment shifts:
Limits on alignment Notifications must be larger:
The Notifications are only intended to allert Operators and Commissioners to an IM alignment shift that may have happened during a time when the CR was not staffed.
What is always true regarding the IM alignments:
When HAM2 ISI trips, it continues to be necessary to trend IM1, IM2, and IM3 alignments to check for shifts that need to be corrected, regardless of the Notifications appearance or lack of appearance on DIAG_MAIN.