The nominal settings for ITMY mode05/06 has stopped working past few IFO locks and both the modes are gradually growing. The nominal setting had a -30 deg phase filter engaged with a gain of -0.01. I tried flipping the sign but the mode was still growing. Hence I switched off FM2 (-30 deg phase filter) and applied a positive gain, which looks to be working (during the last lock) - see screenshot of the ndscope which shows both the modes damping down slowly (both narrow and broad band monitor filters). Given below are the setting which I will try in the next lock and if everything goes fine then I will make the changes in lscparams and accept them in the SDF.Observe file.
IY05/06 FM1 + FM10, Gain +0.01
Also, for IY07 someone found the mode to be growing with -60deg phase filter engaged (I see a comment on lscparams). I tested it this morning and found it to working fine with the -60degree phase filter. I will keep an eye on this mode but at the moment I am going with the following filters and gain,
IY07: FM1+FM2+FM10 Gain +0.1
Accepted the changes for IY07 on SDF.OBSERVE, screenshot is attached below.
I can confirm that the new IY05/06 settings work well for multiple locks. They can be guardianized!
I have confirmed the above settings in the lscparam.
Attaching a plot from last night (6 hours of damping went fine).
