Plant control protection device

A plant control protection device comprising:

• monitoring operation circuitry for performing monitoring operation to keep a plant component in a normal state;
• and
• a protection control circuitry which performs state detection for the plant component and performs process control by transmitting an automatic control signal to the plant component in accordance with a detected state of the plant component, wherein
• the monitoring operation circuitry includes a manual transmission circuitry for transmitting a manual block signal to manually block the automatic control signal from being outputted to the plant component when an unexpected event has occurred, and
• the protection control circuitry includes a control logic circuitry, and in a case where the manual block signal is inputted to the control logic circuitry in a state in which the automatic control signal is inputted to the control logic circuitry, the control logic circuitry blocks the automatic control signal from being outputted to the plant component
• wherein
• the control logic unit includes a logic circuit composed of
• a T flip-flop circuit to which a signal obtained by the automatic control signal passing through a first NOT circuit is inputted as a reset signal and the manual block signal is inputted as a trigger signal for level inversion, and
• an AND circuit which receives the automatic control signal as one input and receives an output obtained through a second NOT circuit from the T flip-flop circuit, as another input.