This morning a 6.2 magnitude earthquake near Vanuatu happened during the commissioning window, so we tested the asc gain reversion scripts Elenna came up with in this alog. It took a little longer than I would have liked to get the scripts working, so we didn't actually transition until basically the peak ground velocities, but the transition went pretty smoothly. I think this eq is tied for the biggest we stayed locked through for all of O4.
Attached image shows ground velocities on the top row (both peakmon and the ITMY Z STS 30-100mhz blrms, second row is the ISC_LOCK state, third and fourth show channels related to the asc transition. Fourth row is the first gain changed by the script CHARD Y, the third row is the SRCL FF gain, which is the last thing changed in the script. The dashed white vertical lines on the CHARD trace and the top row ground traces show the time the transition took to complete.
Even if the transition was a little late I think that this test likely still saved the lock, I have often seen on eqs like this that the IFO stays locked through the peak ground motion, but loses lock some time shortly after, while the eq is still ringing down.
There is still a lot of work to be done as the transition is currently handled by a couple of scripts on the ISI_CONFIG overview medm and the transition will knock us out of Observe, still unclear what the best way to automate this would be, but still a pretty good test.
It's been remarkable and wonderful to see how well we've been surviving earthquakes lately!
This is such a big win, that I suggest we not worry too much about if this pops us out of Observing. If we're able to automate saving the lock, and then going back to Observe when the ground motion is compatible with our usual loops, that's already a huge leap forward on improving our duty cycle.
I have updated ISC LOCK guardian and LSCPARAMS to have the gains for the lownoise ASC and length feedforwards as parameters in LSCPARAMS. Then, TJ helped me figure out how to import LSCPARAMS into these two scripts so it draws those gains from the parameters instead of having them hardcoded. This way, if we decide to update a feedforward or ASC gain, it will also be updated for the earthquake script.
This script also changes ASC filters, but an update to have those filters as parameters in LSCPARAMS is a much more involved change to ISC_LOCK, so I have to think about that one a bit. That means if we change ASC filters, we have to remember to update this script, for now.