Handing off the servo from ALS to LSC for one arm is quite easy because servo filters are pretty much same for ALS and LSC. I demonstrated it Y arm during MI is locked.
We need DARM/CARM-kind of handing off in the near future.
What I did:
1. Brought both arms to IR resonance.
2. Brought X arm to off resonance.
3. Locked MI in bright fringe(why can't I lock in dark fringe, when one arm is on resonance?) using AS55_Q and BS.
4. Ran /opt/rtcds/caltech/c1/scripts/ALS/handofftoLSC.py Yarm to handoff. It decreases ALS gain and increases LSC gain in 30 sec ramp time. It also turns on some filters for LSC. Make sure you turn off filter triggers for LSC.
Below is the plot of what I did. You can see LSC feedback signal gradually increasing and TRY getting more stable.
I was dissapointed with ALS not having any DQ channels for feedback signal. I will make them DQ channels tomorrow.