We asked for the beam to be taken away, and then stabilized the target temperature using the manual controls.
We rebooted using the "Reboot" button on the "IOC Save/Restore/Reboot" window. This took a long time to produce the usual "whiteout" effect but it did come after a while.
Then we did a Normal Restore using the "!" button on the "IOC Save/Restore/Reboot" window. Then we restored PID operation, and asked for the beam to be returned.
Everything seems fine now.
A copy of this log entry has been emailed to: smithg@jlab.org