sheila.dwyer@LIGO.ORG - posted 16:19, Wednesday 12 November 2014 - last comment - 19:17, Friday 21 November 2014(15021)
ITMX has a problem
Here is a collection of suspicious CPS trips on ITMX. This is a problem only on this chamber, which has just cropped up in the last few weeks. It needs to be investigated.
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another example
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Still there, still a problem....
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I made a few plots today. The spectrum of the CPS right before and right after the trip, and the zoom-in time series plot around the time of the trip. I notice that the time that the CPS signal goes down does not match the GPS time indicated the trip exactly (off by a few hundred milliseconds). While making the spectrum I also notice the peak near 4Hz in the "beforetrips" spectrum plot. So I went and look at the LHO summary page and found that there's a small gaussian-looking bump around 4Hz that seems to appear everyday. Probably not very important but just wanted to point that out. Also, please note that V2, H2, and H1 signals are almost perfectly overlapped (that's why you only see two colors). I'll start looking into other related channels that *should* have seen the signals. Although I believe this might be an electronics issue.
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