aLIGO LHO Logbook

H1 DetChar

sheila.dwyer@LIGO.ORG - posted 13:31, Friday 21 August 2015 - last comment - 15:16, Friday 21 August 2015(20752)

glitches in current lock stretches

It seems like Detchar must already be aware of this, but we are having huge glitches durring this lock long lock stretch, which show up in auxiallary degrees of freedom. We were wondering if anyone has checked for things like DAC crossings, or saturations.

Comments related to this report

laura.nuttall@LIGO.ORG - 13:55, Friday 21 August 2015 (20755)

Link

We're currently checking for DAC glitches, hopefully have an answer shortly

andrew.lundgren@LIGO.ORG - 14:09, Friday 21 August 2015 (20756)DetChar

Link

We have checked for software saturations (drives hitting a software limit) and have found none in either of the locks today or the one yesterday. There are no ADC overflows in the OMC DCPDs or POP_A. There are a few DAC overflows in the ETMY ESD, but that can't possibly explain this noise. There are no DAC overflows in any ETM L2 coils. DAC major-carry transition glitches are being checked now.

gabriele.vajente@LIGO.ORG - 15:16, Friday 21 August 2015 (20760)

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I checked for correlations of the glitches with the ASC error signals residual motion around zero, and with suspension witness sensors and optical levers. I couldn't find anything convincing.