Reports until 10:11, Thursday 29 April 2021
H1 AOS
varun.srivastava@LIGO.ORG - posted 10:11, Thursday 29 April 2021 - last comment - 14:40, Thursday 29 April 2021(58787)
ETM Ring-Heater settings restored to O3 for PI damping; Locking today

Georgia, Jenne, Craig, TJ, Daniel, Keita, Varun

Comments related to this report
georgia.mansell@LIGO.ORG - 13:49, Thursday 29 April 2021 (58792)ISC, TCS

When ETMY ring heater was first turned on there was a 0.07W discrepancy between the requested and measured power on the lower segment. DIAG_MAIN complained that the segment might be dead.

We found an SDF diff where, on April 6, the resistance of the lower segment (H1:TCS-ETMY_LOWRESISTANCE) had been modified from 43.6 Ohms to 36 Ohms. Not sure why this would ever change, maybe with a computer restart? Reverting this diff removed the discrepancy, and our ring heater is heating uniformly.

Before fixing this issue we had a lockloss from 46W input power, where a 0.46Hz CSOFT_P instability rang up. Unclear if the mismatched ring heater powers contributed of not.

craig.cahillane@LIGO.ORG - 14:40, Thursday 29 April 2021 (58794)
Power trends for a lock today.
Non-image files attached to this comment