Monitoring and controlling system

A monitoring and controlling system of which monitoring-and-control targets are a plant control device for controlling a plant and a safety protection device for performing safety protection of the plant, the monitoring and controlling system comprising:

• a non-safety system which monitors and controls the plant control device and the safety protection device;
• and
• a safety system which monitors and controls the safety protection device, wherein
• the non-safety system includes a first operation switch for operating the safety protection device,
• the safety system includes a second operation switch for operating the safety protection device, a parameter generation circuit which transmits a parameter to the non-safety system, and a coincidence determination circuit which determines whether or not a parameter returned from the non-safety system and the parameter transmitted from the parameter generation circuit coincide with each other, and
• in a case where the coincidence determination circuit determines that the parameters do not coincide with each other, the safety system blocks an output signal from the first operation switch of the non-safety system.