kiwamu.izumi@LIGO.ORG - posted 20:22, Thursday 04 February 2016 - last comment - 16:01, Friday 05 February 2016(25398)
something is wrong with OMC DCPD whitenings
Masayuki and I noticed that ADC noise in OMC was too high. It turned out that the whitening filters turned off for no obvious reason at around 17:00 pm local according to trend.
Looking at the control screen, we noticed that some channels were not accessible. See the attached. We seem to be able to toggle the analog whitenings and digital anti-whitenings independently now. The rest of the PDs seem OK -- they don't have inaccessible channels.
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Dave, JimB, Kiwamu,
We investigated a bit more today. Interestingly, we discovered that these blank channels never existed before. The only remaining oddity is the fact that we were unable to synchronously switch the analog and digital whitenings by clicking the buttons in the OMC_DCPD screen.