(Elli, Richard, Dave, Rich, etc.)
Last Tuesday around 1pm the readback channels of the TCSX CO2 laser system went crazy. We tracked this to the AI/AA chassis which were not powered. Not clear why, but maybe the power connector fell off, when someone worked in the PEM rack? When the digital system goes down, the chiller doesn't get a temperature setpoint. It will then turn itself off with a fault. In turn the laser shuts off. With the power restored, it was possible to turn the chiller on, and then the laser. Both actions need to be done on the floor. The laser is now back in operation with the requested heating set to 0W. Once we leave we can set it back to 0.3 W. The mask is set to central heating, but the monitor for the annular mask is flaky.
In conclusion: The TCSX CO2 was probably off since last Tuesday 1pm.
The TCS Y arm chiller was off when I investigated the problem. There were no fault codes on restart and the reservoir level was well above the trip level. The X arm chiller was still running. However, the laser controller was showing a flow fault for both the X and Y arm. Toggling the key and re-enabling the gate restored the controller to its operating state.