Glad it's back online. A power cycle waiting a few seconds in between is the simple answer, and that's what you did. The anti-suckback valve in the rough pump shuts when the power goes off to prevent a catastrophic backstream/venting through the exhaust - as would happen in a power outage - so it protects the system. The turbo pump just slowly spins down. When the system comes back up, the default 100/100/100 temperatures are loaded.
So if you had to vent all the way to atmosphere without the computer/software working, you would power cycle, then wait an hour or so for the temperatures to come down to 100/100/100, then turn off the power, wait for the turbo pump to spin down some - maybe ten or fifteen more minutes - and then open the vent valve.