Since Sebastian and Lisa have been trying to look into this, Rich and I had a look at some trends from around the time of these trips.
The ALS DIFF guardian down state exits too soon, moving on to the prepare state too soon (alternatively, it fails to clear the history of DARM, which is par tof the down state but isn't working.) This causes a transient to be sent to the suspension. Of course we need to fix the guardian, but also need to decide if these kind of transients should be tripping the ISIs.
The screen shots below show the input to the suspension from the LSC model, the outputs to the test mass and to the top mass, and the time of the WD trip for two of these trips.
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sebastien.biscans@LIGO.ORG - 14:24, Thursday 05 June 2014 (12235)
I'm still analyzing those trips to be sure that we have a full understanding of what's happening before taking any decision. I should have a full report before the end of the week.
The same thing happened again, this time the plotting script worked.
ETMY sus also tripped just now
Since Sebastian and Lisa have been trying to look into this, Rich and I had a look at some trends from around the time of these trips.
The ALS DIFF guardian down state exits too soon, moving on to the prepare state too soon (alternatively, it fails to clear the history of DARM, which is par tof the down state but isn't working.) This causes a transient to be sent to the suspension. Of course we need to fix the guardian, but also need to decide if these kind of transients should be tripping the ISIs.
The screen shots below show the input to the suspension from the LSC model, the outputs to the test mass and to the top mass, and the time of the WD trip for two of these trips.
Thank you for the follow up Sheila.
I'm still analyzing those trips to be sure that we have a full understanding of what's happening before taking any decision. I should have a full report before the end of the week.