Step by step description of transition from 2arm ALS to Common/Differential LSC for FPMI

- Step 0: Place the frequencies of the arm green beams at the opposite side of the carrier green.

- Step 1: Activate stablization loops for ALSX and ALSY simultaneously.
  (Use LSC filter modules for the control. This still requires correct handling of the servo and filter module triggers)

- Step 2: Activate stablization loops for ALS Common and Differential by actuating ETMX and ETMY

- Step 2 (advanced): Activate stabilization loops for ALS Common by actuating MC2 and ALS Differential by ETMX and ETMY

- Step 3: Transition from ALS Common to 1/SQRT(TRX)+1/SQRT(TRY). Make sure that the calibration of TRX and TRY are matched.
  The current understanding is that the offset for 1/SQRT(TRX)+1/SQRT(TRY) can't be provided at the servo filter. Figure out
  what is the correct way to give the offsets to the TR signals.

- Step 4: Lock Michelson with AS55Q and then POP55Q (PD not available yet) or any other PD, while the arms are kept off-resonant using ALS.

- Step 5: Reduce the TR offsets. Transition to RF CARM signals obtained from POP55I or REFL11I in the digital land.

- Step 5 (advanced): Same as test6 but involve the analog common mode servo too.

- Step 6: Transition from ALS Differential to AS55Q

Independent test: One arm ALS (To be done everyday)

- ALS resonance scan

- Measurement of out-of-loop displacement (or frequency) stability 

- Check openloop transer function

Independent test: Common Mode servo for one arm

- Reproduce Decmber CM servo result of transition from one arm ALS to CM servo
  Insert 1/sqrt(TRY) servo in between?

- How can we realize smooth transition from ALS to POY11?