Reports until 19:55, Tuesday 28 July 2015
H1 ISC
jenne.driggers@LIGO.ORG - posted 19:55, Tuesday 28 July 2015 - last comment - 09:18, Wednesday 29 July 2015(20008)
Global burt restore guardian option

[Jenne, StefanB, Cheryl]

We were having some trouble getting the IMC WFS to converge (WFS came on, looked okay for a while, then started dragging the MC transmitted power down), so we implemented and tested the new global burt restore state, accessible from the ISC_LOCK guardian. 

In the end, the specific problem with the IMC WFS was that the ISC input filters on the M3 stage of the MC mirrors (definitely MC1, maybe others) had gain of zero, so the WFS signals weren't getting through to the optics' outputs. 

The solution we created, which should solve all kinds of problems, is a guardian state that does a global burt restore to a recent set of autoburt snapshots. This state has a date and time hard-coded in the guardian script, although it is easily change-able if we find a more preferable time.  Currently, it is restoring to the autoburts of 28 July 2015, 07:10.  To select this state, you need to go to "manual", since there are no edges to get there from any other state.  When it has finished the restores, it will immediately go to and run the Down state. 

The list of snapshots that are restored is:

Perhaps though, we should just restore *every* snapshot that is captured by autoburt?

Comments related to this report
jeffrey.kissel@LIGO.ORG - 08:28, Wednesday 29 July 2015 (20030)CDS, GRD
J. Kissel, J. Driggers

Use this feature with caution, as we found yesterday evening during the rest of recovery (LHO aLOG 20011), BURT restoring to a single time with the IFO was at low-noise isn't necessarily the right time to BURT restore to, especially until we've caught all of the settings that have fallen between the guardian and SDF cracks.
jameson.rollins@LIGO.ORG - 09:18, Wednesday 29 July 2015 (20032)

I really don't like this as a solution to whatever problem you're trying to solve.  Is there something wrong with the SDF system that is causing you to resort to such a sledgehammer approach?