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Reports until 22:08, Wednesday 19 August 2015
H1 ISC
stefan.ballmer@LIGO.ORG - posted 22:08, Wednesday 19 August 2015 - last comment - 18:06, Thursday 20 August 2015(20698)
PRMI to DRMI transition without dropping lock
As part of the recovery effort today we stumbled upon a way that seems to fairly reliable allow us to transition from PRMI to DRMI (we were 3 for 3 today - we'll try again tomorrow).

The procedure is:

- Let Guardian set up for DRMI locking.
- Misalign SRM
- turn off H1:LSC-SRCL OFFSET, INPUT and OUTPUT
- Let PRMI lock
- make sure H1:LSC-SRCL OFFSET, INPUT and OUTPUT are off (guardian turns on OFFSET), and clear history.
- Pause ISC_LOCK and ISC_DRMI guardian
- Align SRM, wait until it damps down. Today the PRMI always stayed locked in this configuration.
- Turn on H1:LSC-SRCL OUTPUT
- Turn on H1:LSC-SRCL INPUT. DRMI is now locked.
- Turn on H1:LSC-SRCL OFFSET, if desired for mode-hopping suppression


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gabriele.vajente@LIGO.ORG - 09:21, Thursday 20 August 2015 (20707)

Already done at Livingston a long time ago...

https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=11340

stefan.ballmer@LIGO.ORG - 18:06, Thursday 20 August 2015 (20727)
Except this scheme seems much faster than waiting for DRMI...
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