A plant protection instrumentation equipment, comprises, a sensor that detects a process signal indicating a quantity of a state of a plant, a plurality of A/D converters, each of the A/D converters converts the process signal into a digital signal and outputs a value corresponding to the digital signal, a plurality of instrumentation circuits, each of the instrumentation circuits receives the value corresponding to the process signal and performs a logical operation using the value, and a judgment circuit that judges the state of the plant based on outputs of the plurality of instrumentation circuits and outputs an operation signal based on the process signal, wherein each of the instrumentation circuits comprises a logical integrated circuit including a set value comparator that compares the value corresponding to the process signal with a predetermined set value, and outputs a signal when the value corresponding to the process signal exceeds the set value.