SQZ locking is now automated from locking OPO to SQZ angle. The automation will also bring things back up to nominal states when they're kicked out of place. SQZ guardians now have a manager called SQZ_LOCK (Haocun wrote this a while back, now it's ready). SQZ_LOCK manages OPO guardian, PLL (beat note locking), CLF, and LO. SHG guardian is still a stand-alone guardian (I see no advantage of it being managed at the moment).

When the nominal state is requested, SQZ_LOCK will lock OPO on CLF double resonance. Once the node is arrived SQZ_LOCK takes PLL to CHECK_BEATNOTE_2 which put SQZ pump laser frequency close to the IFO carrier and lock CLF. Although SQZ_LOCK manages LO guardian, LO lock still has to be requested by hand at the moment (note that LO_LOCKED_OMC doesn't work yet, so don't go there, the current nominal state is LO_LOCKED_HD).

LO looks at average RF3 beatnote value to determine if it's okay to close the loop. Once it's locked it uses stddev to determined whether or not it's actually locked. LO guardian also looks for rails. If any output rails it will disengage the loop and turn off boosts. In addition it also looks at OPO, CLF, and IMC status.

PLL looks at both OPO and IMC guardian states. If either is not nominal it will go to a state where it waits for both of them to be nominal again. IMC when loses lock usually kicks the reference cavity which is where our PSL LO sample comes from. When PLL is disengage LO will also rail and disengage. This has been tested with several IMC lock losses. All of them successfully came back to nominal state on their own.

Intensity stabilization servo is now a function lives in SQZ_OPO guardian.

The repeated cause of TTFSS EOM railing is LO output rails. So OPO CHECK_EOM state will now close EOM loop if LO outputs are okay and automatically return to nominal state. That will also allow PLL and LO to go back to their nominal states.

Will need some time with the IFO to get the LO OMC guardian to work. And will continue to fine tune the guardian.