A control apparatus, comprising an arithmetic operation device for configuring the control apparatus, and one or a plurality of functional units, the arithmetic operation device comprising: a communication circuit configured for exchanging data with the one or a plurality of functional units through a communication line; a processor configured for executing a user program executing at least one of an arithmetic operation process using data acquired from the one or the plurality of functional units and a generating process of data to be transmitted to the one or the plurality of functional units; and a monitoring circuit that is connected to the communication circuit and the processor, wherein the monitoring circuit is configured to give a power shutdown notification from the communication circuit to the one or the plurality of functional units on the basis of at least one of detection of shutoff of power supplied to the arithmetic operation device and reception of a preliminary notification before the shutoff of the power supplied to the arithmetic operation device, by transmitting a specific frame including a command associated with the process according to the shutoff of the power supply to the arithmetic operation device, from the communication circuit through the communication line to the one or a plurality of functional units, the control apparatus being characterised in that each of the one or a plurality of functional units is configured to execute a process according to shutoff of power supply to the arithmetic operation device upon receiving the power shutdown notification, and to sequentially transmit the specific frame to the respective next one of one or the plurality of functional units to operate one or the plurality of functional units in a safe operation state. a communication circuit configured for exchanging data with the one or a plurality of functional units through a communication line; a processor configured for executing a user program executing at least one of an arithmetic operation process using data acquired from the one or the plurality of functional units and a generating process of data to be transmitted to the one or the plurality of functional units; and a monitoring circuit that is connected to the communication circuit and the processor, wherein the monitoring circuit is configured to give a power shutdown notification from the communication circuit to the one or the plurality of functional units on the basis of at least one of detection of shutoff of power supplied to the arithmetic operation device and reception of a preliminary notification before the shutoff of the power supplied to the arithmetic operation device, by transmitting a specific frame including a command associated with the process according to the shutoff of the power supply to the arithmetic operation device, from the communication circuit through the communication line to the one or a plurality of functional units, the control apparatus being characterised in that each of the one or a plurality of functional units is configured to execute a process according to shutoff of power supply to the arithmetic operation device upon receiving the power shutdown notification, and to sequentially transmit the specific frame to the respective next one of one or the plurality of functional units to operate one or the plurality of functional units in a safe operation state.