After we changed the SEI configuration Guardian nodes to work with the new Fader from B. Lantz (see my alog46297), Jim and I had waited to see how the fader would handle during a lock before automating SC changes in the case of an issue with the BRS. Changing the SC with the fader while in lock has proved to be very successful so I wrote up new code for ETMY_ST1 and ETMX_ST1 SC Guardian nodes.

These nodes watch the BRSX_STAT and BRSY_STAT nodes to see if they are are in the FAULT or DAMPING_HIGH_VEL states. If one of these monitor nodes goes into either of these states, then it will fade off the sensor correction for that cucumber chamber until the monitor node is okay again while it waits in the BRS_FAULT_SC_OFF state. Or, if the SC node is transitioning to a state that uses a BRS corrected SC and the stat node is not okay, then it will wait in the BRS_FAULT_SC_OFF state until it is resolved.

The circumstances for the BRS stat nodes to go to either fault state are very uncommon, so we should rarely see this. The reason to automate this process is because if the BRS is feeding a signal to the ISI that is not healthy, we will most likely lose lock.

I tested it out today and all seemed to work as expected. I created a new brs_states.py that will import the normal states.py that every other SC node uses. This allows the state creation to stay automated, while giving users freedom to change/add configurations easily. The brs_states.py adds a new state (BRS_FAULT_SC_OFF) and adds a decorator to the idle states that use a BRS sensor corrected signal. I attached the code if anyone is interested.

(Edited typo)