Reports until 02:25, Tuesday 27 September 2016
H1 AOS
sheila.dwyer@LIGO.ORG - posted 02:25, Tuesday 27 September 2016 (29994)
Locklosses possibly caused by glitches in DRMI

Lisa, Sheila

Since yesterday afternoon, we have struggled with locklosses that happen 5 to 15 minutes after we power up.  

There are a dramatic, very short, glitches in DRMI LSC channels.  It also shows up in the ASC channels, but after LSC.  

Some lockloss times are:

2016-09-27 06:40:33 UTC

2016-09-27 05:39:35

Some times (within a few seconds) when saw the glitch but we did not loose lock are:

1158999031

1158998954

1158999031

 

As a test to see what the problem could be, I commented out the lines in REDUCE_MODULATION_DEPTH where the POP9 to SRCL matrix element is changed.  With this matrix element out, I didn't see these glitches, but the problem did seem intermittent so this could be a coincidence. 

Images attached to this report