Louis, Jenne, TJ, Sheila
Today we continued to try to transition to the new Darm configuration, which we had suceeded in doing in December but weren't able to repeat last week (75204).
In our first attempt today we tried a faster ramp time, 0.1 seconds. This caused immediate saturation of ETMX ESD. We struggled to relock because of the environment.
Because Elenna pointed out that the problem at roughly 3 Hz with the earlier transition attempts might have been the soft loops, we thought of trying to do the transition before the soft loops are engaged, after the other ASC is on. We tried this first before transitioning to DC readout which wouldn't work because of the DARM filter changes. Then we made a second attempt at DC readout. We also lost lock due to a 2 Hz oscialltion, even without the soft loops on.
Some gps times of transitions and attempt:
- 1387034100 succsesful transition from December
- 1388520329 attempt from last week with 5 second ramp
- 1388520329 attempt from last week to transition to the NEW DARM in TRANSITION_FROM_ETMX and LOWNOISE_ESD_ETMX with a 5 second ramp
- 1388952732 attempt from today to transition with a 0.1 second ramp, imediate saturation of ESD
- 1388961745 attempt at 2W with soft loops off (5 second ramp)
Adding two more times to this list:
The second screenshot here shows the transitions from Dec 13th, 14th, and 19th. These are three slightly different configuration of the UIM filters and variations on which PUM boosts were on when we made the transition. On the 14th the oscillation was particularly small, this was with our new UIM filter (FM 2 + 6) and with both PUM boosts on L2 LOCK FM1,2,10 already during the transition. This is the same configuraition that failed mulitple times in the last two weeks.
Today I went back to three of these transitions, December 14th (1386621508 sucsesful no oscillation) and Jan 4 (1388444283) + Jan 5th (1388520329) which were unsucsesfull attempts. It also seems as though the only change to the filter file since the Dec 14th transition is a change copy the Qprime filter into L1 drivealign, which has not been used in any of these attempts (this can't be used because tidal is routed through drivalign).
In short, it doesn't seem that we made a mistaken change to any of these settings between December and January which caused the transition to stop working.