edmond.merilh@LIGO.ORG - posted 16:07, Saturday 22 October 2016 - last comment - 19:02, Saturday 22 October 2016(30751)
Shift Summary -Day
- The day started with not much hope of taming PI modes.
- After deciding to do an initial alignment, it was discovered after Sheila finally arrived that SR2 had been knocked off alignment so much that SRC_ALIGN kept shaking and tripping watchdogs in HAM5 when trying to center.
- Terra had the answers to the PI issue regarding bandpass filters aimed in the wrong range but there was no communication about it during the night.
- Further difficulties locking PRMI/DRMI were addressed after Stefan got here. Mainly gains and some alignment.
- Sheila taking data from new TCS adjustments
- the remainder of the shift was an occassional exercise in damping PI modes.
- Mike Landry stole someone's lunch.
My earlier comment assumption was correct: during the settling of the recent ring heater changes, Mode26 had shifted outside of the usual guardian-controlled bandpasses; an already existing filter needed to be turned on. After this, we powered up and damped with no problems. Locked for 2.5 hours at this point needing only normal phase changes. I walked Ed through how to check on this and change the filter, but this large of change only occurs after a ring heater change so will not be a normal issue operators need to worry about.
Reminder that I've requested to be called anytime there is a persistant PI problem.
I've added step-by-step instructions for how to attempt to handle this scenerio in the Operator PI Wiki (under 'If a PI seems unresponsive') if for some reason I can't be reached. PI Wiki can also be opened from PI medm screen. Working on automating this.