Eurocrate key turning reboots today morning for c1psl and c1aux.c1auxex and c1auxey are also down but I didn't bother keying them for now. PSL FSS slow loop is now active again (its inactivity was what prompted me to check status of the slow machines).

Note that the EPCIS channels for PSL shutter are hosted on c1aux.But looks like the slow machine became unresponsive at some point during the weekend, so plotting the trend data for the PSL shutter channel would have you believe that the PSL shutter was open all the time. But the MC_REFL DC channel tells a different story - it suggests that the PSL shutter was closed at ~4AM on Sunday, presumably by the vacuum interlock system. I wonder:

1. How does the vacuum interlock close the PSL shutter? Is there a non-EPICS channel path? Because if the slow machine happens to be unresponsive when the interlock wants to close the PSL shutter via EPICS commands, it will be unable to. The fact that the PSL shutter did close suggests that there is indeed another path.
2. We should add some feature to the vacuum interlock (if it doesn't already exist) such that the PSL shutter isn't accidentally re-opened until any vacuum related issues are resolved. Steve was immediately able to identify that the problem was vacuum related, but I think I would have just re-opened the PSL shutter thinking that the issue was slow computer related.