Reports until 17:33, Saturday 13 February 2016
H1 ISC
evan.hall@LIGO.ORG - posted 17:33, Saturday 13 February 2016 (25534)
ALS X alignment is very slow

{Kiwamu, Evan}

We had another instance of the interferometer coming into resonance with low recycling gain, even though this was the first lock after an initial alignment.

In this case, the issue was solved by redoing the initial alignment, and letting the green ALS alignment loops integrate about 20 minutes. In this case that might have been overkill; from the attached plot of the ITMX control signals (which contain several instances of offloading to the sliders: 20:54:00, 20:59:00, and 21:08:00), one can see that the control signal took about 10 minutes to reach 90% of its asymptotic value.

We already knew that some of these loops were quite slow, but 10 minutes borders on excruciating. We should try to make these faster.

Images attached to this report