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Reports until 19:17, Friday 11 November 2016
H1 OpsInfo
terra.hardwick@LIGO.ORG - posted 19:17, Friday 11 November 2016 - last comment - 19:26, Friday 11 November 2016(31428)
PI gain check

Operator task request

Now that we're at lower power, we'd like to double check what PI's actually need to be damped. We still have damping settings set up on all the modes that rang up while at 50 W, but it looks like most of them are no longer actually needed. I trended the past several days of locks and only Modes 26, 27, 28, (and maybe 3) rang up enough to engage their damping loops. We'd like to turn off the damping for the other modes and watch and make sure that they really don't need it. 

To check:

1. Once you've passed DC READOUT, guardian has turned on all the usual PI gains. Write the gains down (or I've put them in the comment below) so that you can quickly put these values back in if needed.

2. Set the gains of Modes  1 - 25   (edited to now include keeping Mode 3 on) 1, 2 , 4 - 25 to zero. Do Not zero Modes 3, 26, 27, 28 as we are definitely actively damping those. Just do this directly on the main PI medm screen under the 'gain' column. 

3. Watch the modes throughout the lock. The StripTool will still give the same ring up info as always and the DTT screen is a good way to keep an eye on if something is growing. 

4. If a mode starts to clearly ring up, put back in the original noted gain value and damp as usual. Make a note in the log. 

I've chosen not to just auto set the gains to zero already in case the operator is busy for now. Let's get a few longer locks that are more closely watched and confirm we really dont need damping on. 

Comments related to this report
terra.hardwick@LIGO.ORG - 19:26, Friday 11 November 2016 (31429)
Mode Gain
2 5000
3 -3000
9 -1000
10 -1000
17 1000
18 -5000
25 -1000
26 -3000
27 5000
28 3000
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