TITLE: 09/14 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
INCOMING OPERATOR: Ibrahim
SHIFT SUMMARY: More troubleshooting today on H1 locking, primarily focused on getting through the CARM_TO_REFL transition and RESONANCE states. See my morning alog for details on the first half of the day; the rest I list here:
- After a discussion online between people, decided using a different TR CARM offset may be the path forward
- Reverted my earlier change of LSC_TR_REFLAIR9_CARM_TO_REF gain in lscparams back to -0.8
- Relocked - held in CARM_5_PICOMETERS and stepped TR_CARM offset
- Took TR CARM transfer function between steps to check UGF doesn't get too low
- Settled on -52 as a good offset
- Moved to CARM_TO_ANALOG, PRG got noisy, waited here about 10 sec
- Moved to RESONANCE, PRG less noisy, but DHARD control signals got glitchy and lockloss
- 2 Hz ringup seen in DHARD and DARM
- Relocked - after CARM_5_PICOMETERS lowered TR CARM offset to -52
- Requested CARM_TO_ANALOG, lockloss soon after entering RESONANCE
- Relocked - lowered TR CARM offset again after CARM_5_PICOMETERS
- Turned off DHARD loops
- Requested CARM_TO_ANALOG; lockloss at same place in RESONANCE
- Realized RESONANCE turns DHARD gains back on, temporarily commented these lines out for next attempt
- Relocked - did NOT lower TR CARM gain
- Turned off DHARD loops
- Requested RESONANCE, lockloss at same place
- Relocked - lowered TR CARM offset again after CARM_5_PICOMETERS
- Turned off DHARD loops
- Requested RESONANCE, lockloss at same place
- Relocked - lowered TR CARM offset even lower to -55
- Left DHARD on
- Lockloss before even leaving CARM_5_PICOMETERS
- -55 is too low of an offset
- Relocked - lowered TR CARM offset to -52
- Left DHARD on
- Lockloss at start of RESONANCE again
- Relocked - lowered TR CARM offset to -52
- Uncommented DHARD gains in RESONANCE
- Moved to CARM_TO_ANALOG, PRG noisy but otherwise stable
- Ibrahim starts taking measurements
Generally locking has been very easy today up through CARM_5_PICOMETERS and alignment has been good.