Reports until 17:38, Sunday 17 May 2015
H1 ISC (DetChar)
jeffrey.kissel@LIGO.ORG - posted 17:38, Sunday 17 May 2015 - last comment - 20:45, Sunday 17 May 2015(18492)
IFO left attempting to lock 
J. Kissel

Robert has left the site, and I have to head out. After the long stretch's lock loss, I needed to tweak the ETMY alignment by ~0.5 [urad] before the green WFS were able to take over. Other than that, the lock acquisition system has taken over and run with it. So far there have been two failed attempts in the same way -- it gets all the way up to the middle of the power increase (right as the CSOFT and DSOFT loops come on) and then it looses lock. Maybe the ITM OL damping loops need to be off for the lock acquisition sequence and then turned on later? Dunno.

The IFO disappears for a few days starting tomorrow. Lots of electronics need swapping. Hopefully it will be quick to return to this great Sunday's kind of locking around Thursday or Friday.
Comments related to this report
sheila.dwyer@LIGO.ORG - 19:43, Sunday 17 May 2015 (18494)
Link

The asc engages, before the power up, but we haven't added a pause in the guardian to let the asc loops converge before the power increase. We were doing this by requesting the ASC engage state, waiting 30 seconds to a few minutes there before requesting LSC FF. A fixed time pause could easily be added there which could probably prevent these kind of locklosses for now
evan.hall@LIGO.ORG - 20:45, Sunday 17 May 2015 (18495)
Link

ITM pitch oplev damping can be left on the whole time.

Occasionally after a lockloss the loops may ring for a while, but I decreased the output limiting from 20 000 to 1000 ct to (hopefully) prevent this.