Jennie, TJ, Camilla
The Operator team has been seeing more locklosses at state 557 TRANSISITON _FROM_ETMX, more so when the wind is high. Times: 1397719797; 1397722896; 1397725803; 1397273349, 1397915077
Last night we had a lockloss from 558 LOWNOISE_ESD_ETMX with a 9Hz ITMX L3 oscillation, see attached. Compare to a successful transition (still has glitch).
Note that there is a glitch ~30s before state 558 in both cases. H1:SUS-ETMX_L3_DRIVEALIGN_L2L and _L3_LOCK_L filter changes happens here. Are ramp times finished before these changes?
The timing of the glitch is 2 m 55 seconds after we get to state 557, this is the same time as in the 4 of the last 6 state 557 locklosses.
Louis, Camilla. Investigations ongoing but the timing of this glitch is suspiciously when the H1:SUS-ETMX_L1_LOCK_L gain and filters are changed, tramp is 1secinds but FM2 and FM6 foton filters have a 3 seconds ramp. There is an INPUT to this filter bank before the gain and filters are turned on. Plot attached.
In 77640 we show that the DARM1 filter change is the cause of the glitches/locklosses.