Camilla, Louis
We dropped out of Observing at 7am PST test the new DARM loop config:
- the new DARM loop config, navigated to by going to NLN_ETMY -> NEW_DARM, seems to be stable. We were able to sit there for several minutes without issue.
- Camilla took a quick look at MICH FF settings while in 'NEW_DARM'. She will follow up with more info on that.
- We lost lock again while trying to cal measurements in the NEW_DARM state. Still trying to figure out what's happening there; clearly reducing the amplitudes by 50% (LHO:74883) wasn't nearly enough. It seems we kicked the IFO hard enough for ISI_ETMX watchdogs to trip.
due to the lockloss we did not get to test the DARM_RECOVER guardian state.
When the excitations started, the ETMX HEPI, ISI and SUS WDs tripped and (~5 minutes later) the hardware watchdogs for both SEI and SUS.
With all watchdogs tripped, I cleared history of the L2 LOCK L stage of ETMX as this was outputting very large numbers. M0 DAMP also seemed to be outputting very large numbers, I tried cleaning history but it seems like this was physically ust moving a LOT, plot attached.
Rahul via phone walked me though checking that ETMX is ready to be untripped: output counts changing by hundreds not 10,000's. We then reset SUS SW WD (cds > SWWD > ETMX) and untripped the SUS ETMX WD, Rahul said if it was still ringing very badly we would turn on M0 DAMP damping loops one-by-one but they already looked on so I took the GRD to DAMPED then ALIGNED.
After we got ETMX SUS back to usual, I reset the ETMX SEI SWWD and I followed the procedure to uptrip SEI (from wiki, HEPI then ISI). Once this was done Ryan took us to maintenance mode.
The new DARM configuration is shown in this plot is veery effective in reducing the ESD RMS, as shown in the plot below. The blue curve is one hour of normal configuration, showing the ESD total RMS as a function of time. The orange trace is during the test: the first few hundreds of seconds are still the nominal configuration, while between ~1000 and ~2000 seconds the new DARM configuration is running. The RMS is reduced well below the minimum of the normal configuration.
Unfortunately the was no clean data collected during this time to see the effect on the strain.
The MICHFF FM4 that we fit for cold OM2 74877 was actually very good for tis new DARM configuration green trace, much better than the FM1 we fit for the new DARM configuration 74817.
DARM didn't look great at 30-100Hz in either configuration, maybe this could be as the calibration is wrong.