Today new versions of the single arm IR locking nodes, NARM_LOCK and WARM_LOCK, have been put in operation and tested. This serves three purposes:

1. allow a (partial) lock with reflection signals, namely SPRB_B4_6MHz_I (for both arms), as fallback configuration in case the B7/B8 beams are not available (up to a point, more on this later);
2. ease the integration with the ALS nodes, ALS_NARM and ALS_WARM, and the forthcoming management of the four of them by the single "arms" node;
3. polish the code, that was not done in a very long time.

Here are the main changes:

• we now import virgotools as we are supposed to (from virgotools.everything import *);
• the state indexes have been rethinked and changed;
• the state names have not changed aside the two handoff states, which are now HANDOFF_B{7/8}_TO_B4 and HANDOFF_B4_TO_B{7/8};
• some states have been removed from the drop down menu (request = False) as they should not be requested manually; if really needed, the usual full states list window should be used instead;
• the path for the lock with B{7/8}_56MHz_I has been removed entirely, as it was basically never used;
• the lock with the B4_6MHz_I signal has been re-implemented; a few notes about it:
  • since that we are forced to use the Guided Lock to acquire the lock of the arm, it is not possible to lock an arm directly with the B4 beam, as the Guided Lock is strongly dependent on the availability of B{7/8}_DC; instead, we can lock with the usual B{7/8}_6MHz_I signals and then handoff the control to B4_6MHz_I; this has been enforced by breaking the symmetry of the two locking paths by severing the edge between the ACQUIRE and the ACQUIRE_WITH_B4 states; so, selecting directly the LOCKED_WITH_B4_BOOST_ON state will lock the arm as usual and then perform the handoff (see next point);
  • selecting the LOCKED_ON_B4_BOOST_ON state will ask the transition through the HANDOFF state; in the final state, aside the obvious change of sensor, the drift control is disabled (as it relies on B{7/8}_DC) and the decorator which checks if the arm is still locked is changed from a "min" check on B{7/8}_DC to a "max" check on B4; due to the logic of Guided Lock triggers and flags, it is also needed to force a relay to be always 1 (LSC.B{7/8}_GL_DC_TRIG_LO);
  • the inverse handoff is possible, selecting back the usual LOCKED_ON_B{7/8}_BOOST_ON state; given that this should be done after verifying the availabilty of the B{7/8} beam, doing so will enable again the drift control, change the decorator back to the B{7/8} one and put the aforementioned relay back to automatic mode (-2); this very last thing is done also in the DOWN state, in case of unlock;
  • the automatic check of the availability of the B4 PD (which should be B4_PD2) will be tested and added tomorrow;
  • the lock on B4 was tested on both arms and the logic works, disabling B{7/8}_DC did not unlock the arms;
• the ACQUIRE state has been made a little more beam-independent (aside the Guided Lock parameters), as one would want the two paths with B{7/8} and B4 available; as said above, it will be studied if this is really possible or if the initial lock is forced to be using B{7/8};
• there are two new states, ALIGNING_{NORTH/WEST}_ARM and ALIGNED_{NORTH/WEST}_ARM, which realign the arms; this was earlier embedded in the ACQUIRE state, but it had to be separated and anticipated in order to ease the forthcoming management of all the four single arm nodes;
• there is a tentative WIP state, named for now OFFLOADED_TO_MANAGER: in this state nothing is done or checked, and this is the point: it will be used as a "parking" state for the node once everything is under the direct control of the single "arms" node; it can be only reached (but not requested manually) from the "final" state for these nodes, LOCKED_ON_B{7/8}_BOOST_ON.

The new node layout is attached, PLEASE RESTART ANY INSTANCE OF THESE NODES CURRENTLY OPEN, as the states list in the drop down menu has changed.