Reports until 19:42, Wednesday 26 July 2017
H1 General
edmond.merilh@LIGO.ORG - posted 19:42, Wednesday 26 July 2017 - last comment - 21:20, Wednesday 26 July 2017(37802)
Violin Damping

Jeff K., Ed M.

ETMX mode 4 damping was in progress from Day shift when I arrived. Jim had found good results at 0 phase, 75gain and both YAW and PIT to activate on via the DARM damp matrix. I was slowly increasing the gain until I hit a "wall" where the RMS leveled off. Empirical switching on and off of various components/combos of the filter bank ended up with me activating on L/P/Y @ -60phase and 95gain. Modes 2 and 3 were also being tended as they would seem to be excited by actions to mode 4. These settings have brought H1 completely out of fundamental violin frequency domination (for the time being).

As I noted in my previous aLog, care (which I did not heed), must be taken when attempting to damp violin modes while in Observing. While it is acceptable to do so, one must UNmonitor the filter bank channels to be used or the SDF will bounce the intention bit out of Observing. As of now there is a ragged smattering of monitored vs unmonitored channels for these modes. Below are a couple of stragglers that had to be accepted as a result of our successes.

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edmond.merilh@LIGO.ORG - 19:45, Wednesday 26 July 2017 (37804)

Here are the filter settings du jour:

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edmond.merilh@LIGO.ORG - 21:20, Wednesday 26 July 2017 (37805)

Channels were unmonitored for this task and have since been restored to their original "monitored" state: H1:SUS-ETMX_L2_DAMP_MODE_MTRX_1_4; H1:SUS-ETMX_L2_DAMP_MODE_MTRX_2_4; H1:SUS-ETMX_L2_DAMP_MODE_MTRX_3_4