ibrahim.abouelfettouh@LIGO.ORG - posted 14:07, Thursday 14 December 2023 - last comment - 14:49, Thursday 14 December 2023(74814)
Lockloss 21:19 UTC - While Taking Simuline Calibration Measurements
21:18- UTC - Calibration Measurement (simuLines) started.
21:19 - UTC - Lost Lock
- Hepi EX watchdog tripped
- ISI EX Stage 1 and 2 watchdogs tripped
- The lockloss may have been caused by driving ETMX too hard with the new EX configuration. Louis is currently working to improve simulines so that it doesn’t happen again (see screenshot).
- Another potential cause is a 63/64hz ring-up - investigation ongoing.
Potentially (but unlikely) related - Oli also lost lock during Simulines during their shift - alog 74716
Relocking Now as of 21:20 UTC.
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Attached shows that the sus excitations began shortly before the oscillation begain, but that the DARM1 and SWEPTSINE excitations began after the oscillation. Investigation still ongoing as to what caused the lockloss though.
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We plotted the fast 16kHz channel of H1:SUS-ETMX_L2_CAL_EXC_OUT_DQ and can see this excitation caused the ETMX oscillation and lockloss. Sheila/Jenne state this is not that surprising as the gains have been changed the ETMX filters. Plot attached.
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