Camilla, Oli

Recently, because of the PSL/IMC issues, we've been having a lot of times where the IFO (according to verbals) seemingly goes into READY and then immediately goes to DOWN because the IMC is not locked. Camilla and I checked this out today and it turns out that these locklosses are actually from LOCKING_ARMS_GREEN - the checker in READY that is supposed to make sure the IMC is locked was actually written as nodes['IMC_LOCK'] == 'LOCKED' (line 947), which just checks that the requested state for IMC_LOCK is LOCKED, and it doesn't actually make sure the IMC is locked. So READY will return True, it will continue to LOCKING_ARMS_GREEN, and immediately lose lock because LOCKING_ARMS_GREEN actually makes sure the IMC is locked. This all happens so fast that verbals doesn't have time to announce LOCKING_ARMS_GREEN before we are taken to DOWN.

To (hopefully) solve this problem, we changed nodes['IMC_LOCK'] == 'LOCKED' to be nodes['IMC_LOCK'].arrived and nodes['IMC_LOCK'].done, and this should make sure that we stay in READY until the IMC is fully locked. ISC_LOCK has been reloaded with these changes.