ibrahim.abouelfettouh@LIGO.ORG - posted 09:43, Friday 17 October 2025 - last comment - 10:34, Friday 17 October 2025(87540)
PRMI to MICH timer changed to 10 mins
Sheila, Ibrahim
PRMI locking waited a long while with high counts before going into MICH so Sheila changed the timer from 20 mins to 10 mins.
Tony, Ibrahim, Sheila
Referencing 44348, Ibrahim and I went back to Sept 12 2018, and found a time when PRMI locked in 3 minutes. At that time, the MICH trigger level was 6, and based on the minute trend max the MICH TRIF channel was around 70, 9% of the max value. In locked DRMI, the trigger channel was 70, and the trigger level was 40, so 57% of the locked value, and the trigger matrix had a value of 1.
On March 31st, 2025 I changed the trigger matrix from 1 to 2 for PRMI and DRMI 83655, at that time the locked value on POPAIR 18 NORM was only 32 perhaps because the diode was misalinged, the trigger threshold was 37, so with the factor of 2 the trigger was still 43% of the locked value for DRMI. After the vent where ISCT1 was moved and realinged, POP 18 NORM has been back at around 70 counts when DRMI was locked.
We removed the factor of 2 from the input matrix, and loaded the DRMI guardian. After this we have had one short PRMI lock, where we can see that something is moving a lot and PRMI is not well aligned.