When Patrick relocked the IFO we had a repeat of the problem with the CLF locking that caused us some difficulty last Thursday (alluded to but not really explained in 54822).
What happened last Thursday: I unlocked the squeezer, changed the green power, adjusted the temperature for the nonlinear gain, and tried to go back to squeezing. The CLF would not lock, the problem seemed to be with the CLF ISS, which would saturate every time it was engaged, the guardian would then toggle it off and on again repeatedly. The symptom of this is that SQZ MANAGER is stuck in LOCK_CLF and won't move on. Last Thursday Keita and I tried a variety of button clicking. Eventually, Daniel came in, and as we were talking about the problem it fixed itself.
Today, when faced with the same problem:
- I requested LOCK_OPO from the SQZ_MANAGER guardian.
- I then opened the CLF ISS screen (linked from squeezer overview shown in black rectangle here, this rectangle might be outlines in yellow when the ISS is not working correctly). On the ISS screen I clicked the SERVO/RAMP button as shown in the black rectangle here. This button enables the servo to run when SERVO is shown (the configuration in the screenshot has the servo enabled), and enables a BNC input labeled ramp on the front panel when it says ramp (which disables the servo). When I manually enabled the servo, it saturated at first so that the green limiter box was outlined in red, but stopped saturating and seemed to be working OK after a few seconds.
- I requested LOCK_CLF from the SQZ_MANGER and waited for it to arrive which it did without a problem.
- I reset the SQZ_MANAGER request to SQUEEZING, which opens the beam diverter and let us go back to squeezing.
I don't know for sure if what I did solved the problem, but I would suggest that operators who encounter this situation try this procedure, and let us know how it works.
