david.barker@LIGO.ORG - posted 15:38, Saturday 02 December 2023 (74547)
ISI ST1 DAC drives railed at time of earthquake
The attached plot shows the ST1 H1,H2,H3 DAC drives for, from upper to lower, ETMX, ITMX, ETMY, ITMY.
H1=blue, H2=orange, H3=green.
ETMY does not rail at all, ITMY all 3 rail for 6 seconds, ITMX H1,H3 rail for 7 seconds, ETMX all 3 rail for 12 seconds.
ETMX only differs from ITMY in the length of time the DAC drives are saturated at 10V (12 sec vs 6 sec).
Images attached to this report
