In most applications, there are two isolation valves in the vacuum foreline; one near the chamber exit for process isolation and one directly upstream of the pump for preventative maintenance work.
The Rapid Isolation Valve can be triggered a number of ways, including:
Power to the pump - many pumps have accessory relays which can be easily tapped.
Programmable Automation Controller (PAC) or equivalent device providing logic.
Pressure Sensors, based either on a threshold pressure or a rate-of-rise.