Jim, Elenna
We had a 6.6 earthquake begin rolling in from Panama, so Jim and I tried to take the ASC arm control loops to the high bandwidth state. I also turned off the LSC feedforward which drives the ETMY PUM.
This obviously creates a lot of noise in DARM, but we are curious to see if it helps us ride out a large earthquake.
This consists of:
Some of these things can be done by hand, but others, like transitioning filters and gains together have to be done with guardian code to ensure they are done at the same time. I copied and pasted lines of code into a guardian shell.
These are the lines of code that will do everything I mentioned above:
ezca.get_LIGOFilter('ASC-CHARD_Y').ramp_gain(300, ramp_time=10, wait=False)ezca.switch('ASC-CHARD_Y', 'FM3', 'FM8', 'FM9', 'OFF')ezca.switch('ASC-DHARD_Y', 'FM1', 'FM3', 'FM4', 'FM5', 'FM8', 'OFF')ezca.switch('ASC-CHARD_P', 'FM9', 'ON')ezca.switch('ASC-CHARD_P', 'FM3', 'FM8', 'OFF')ezca['ASC-CHARD_P_GAIN'] = 80ezca.get_LIGOFilter('ASC-DSOFT_Y').ramp_gain(30, ramp_time=5, wait=False)ezca.get_LIGOFilter('ASC-DSOFT_P').ramp_gain(10, ramp_time=5, wait=False)ezca.switch('ASC-DHARD_P', 'FM4', 'FM8', 'OFF')ezca['LSC-PRCLFF_GAIN'] = 0ezca['LSC-MICHFF_GAIN'] = 0ezca['LSC-SRCLFF1_GAIN'] = 0I saved this as a script called "lownoise_asc_revert.py" in my home directory. This is a bit of a misnomer since it also reverts the LSC feedforward.
We are still locked so far, but we are waiting to see how this goes (R wave just arrived).
We lost lock when the ground motion got to be about 2.5 micron/s.
This was a "large earthquake" aka within the yellow band on the EQ response zone plot. Since these earthquakes are highly likely to cause lockloss, Jim and I are thinking we could try this high bandwidth control reversion for these earthquakes to see if this can help us survive the earthquake. This would take us out of observing and kill the range (we were at about 70 Mpc before the lockloss), but we could then go back to lownoise once the earthquake passes.
Jim also thinks he can make some adjustments to other seismic controls, but I'll let him explain how that would work since he is the expert.
I refined the script to include some sleeps, and wrote another script to revert the reversion so it will put the ASC and LSC feedforward back in the nominal low noise state.
Both scripts are attached. They should be tested!
I have added buttons to run modified versions of Elenna's scripts to my seismic overview ISI_CONFIG screen, the smaller red and blue buttons that say "ASC Hi Gn" and "ASC Low noise" in the upper left, but I don't think we are ready to suggest anyone use them yet. I added a bit of code to ask if you are sure, so they shouldn't be very easy to launch accidentally. I'm trying to compile some data to estimate how much run time we lose or could gain before investing much more effort in automating this.