It seems like the LVEA temperature is not as stable as it should be, and among other things this might be correlated to the slow trend of ALS diff signal going down. It used to be 0dBm, now it's -8 to -10 dBm.
Since diff (X-Y) is degrading much faster than comm (X-SHG), and since it's degrading faster than the SHG power, this is probably just an alignment of some steering mirror on ISCT1. This needs to be fixed tomorrow during the maintenance.
Keita and I looked at zones 4 and 5 temperatures (Output MC and Input MC ) and noticed that they are oscillating in opposition.
In response I have done the following;
Reduced heat zone 3A (from 10ma to 4ma) - this is a reduction of ~33kw or one stage of a 3 stage heater.
Reduced heat zone 5 (from 10ma to 8ma) - Variac controlled - not sure of the power reduction but duct temperature dropped by ~5 degF.
Reduced chilled water setpoint to 43F from 47F to provide more control authority for the chilled air portion of the air handler. The face bypass damper has been swinging from rail to rail for the last few days.
No warranties are implied.
Bubba and I will continue to monitor and adjust.
Temperature of the LVEA is controlled based on the average called H0:FMC-LVEA_CONTROL_AVTEMP. Don't expect H0:FMC-LVEA_AVTEMP to behave as nicely.
