jeffrey.kissel@LIGO.ORG - posted 17:41, Monday 17 July 2017 - last comment - 10:08, Tuesday 18 July 2017(37570)
Active Platforms vs. and Angry Earth
J. Kissel
As we're getting slammed by another earthquake, I wonder if there can be a few things that team SEI can change in order to get the SEI platforms back to DAMPED (HEPI robust isolated on L4Cs, HAMs Damping with GS13s, BSC ISIs damping with L4Cs and GS13s) and optics back to DAMPED as soon as possible. Here're the flaws I see at the moment:
(1) SEI_CONFIG manager doesn't turn off BSC-ISI Z sensor correction (at least in EARTHQUAKE_v2), so giant EQs like the current still push HEPI in Z enough that it makes the T240s angry and trips the ISI's watchdog, even though the T240s aren't yet involved in any active control. The SEI manager should have a state where it turns off ALL sensor correction, not just horizontal sensor correction.
EDITNevermind => I had not read Jim's updates to the SEI_CONFIG Guide. We should be in LARGE_EQ_NOBRSXY, and that does indeed turn off ALL sensor correction.
(2) This may be hard, but it would be best if the T240s weren't in the watchdog system until they're used.
Just planting the seed for discussion, no need to pull out ECR pens just yet.
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Re #2, My recollection was that it was ignored or else while it was riled up it would trip which it does not. Regardless, I reviewed the model and indeed I recalled correctly that the T240s are ignored in the WD as long as all the Isolation Gains are zero. Not sure the situation that Corey was experiencing during the EQ ring-down that suggested the T240s were the problem.