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Reports until 07:54, Saturday 24 September 2016
H1 AOS (DetChar)
joshua.smith@LIGO.ORG - posted 07:54, Saturday 24 September 2016 (29955)
ASC AS_C INMONs overflowing on 9/23 but not 9/24

Josh, Andy

Summary: The ASC AS_C INMONs were overflowing on 9/23 but not 9/24. We're not sure if this has any negative consequences. 

During O1 we were asked to report any overflows that happened in analysis ready time. The summary page for overflows for 9/23 had a lot of entries but nearly all of them were at the lock loss. Of the handfull of things that overflowed for longer periods we looked at the ASC AS_C INMONs.

These overflowed the entire lock on 9/23 (like in fig 1) but were not overflowing in O1 (fig 2) and were not overflowing in the most recent lock on 9/24.
The histograms of the values for segs 2 and 4 are compressed around -32768 (though these are not integer counts and that value is exceeded) (fig 3).
We're not sure if this translates into problems for AS_C, but there is somewhat elevated noise in those channels now compared to O1 (fig 4,5) and those channels are used for ASC SRC2 which in turn has ~5-10Hz coherence with SRCL (fig 6).
But AS_C channels have not much coherence with DARM (fig 7).  

We thought it was worth reporting even if there isn't an obviously bad consequence. 

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