The glitches seem to come from the slow controls output and temporarily result in an actuation voltage of +-10 V even when the limit for that channel was set to +-2 V in the PID script. This triggers the 'WIN' light and a beep from the ITC 502 while also losing the lock.

Aaron and I also had observed this last week.

[shruti, chris]

We were able to measure the loop transfer functions with the latest settings of KI=0.5 and PDH_CTL offset=2000cts on the slow control without being affected by the glitches too much. Chris also set up all the slow control channels so that they can be viewed with ndscope. In this we could also see that the transmission monitor sometimes glitched but the loop remained locked.

Attachment 2:

Updated measurement similar to elog 2759