CONTROL DEVICE, CONTROL SYSTEM, AND CONTROL METHOD

A CPU includes an auxiliary power supply, a power receiver, a storage, an abnormality detector that detects an abnormality occurring in at least one device of devices including the CPU and a plurality of external devices including a main power supply unit and stores, into the storage, abnormality data including data indicating the device with the abnormality, an indication controller that provides, based on the abnormality data, information indicating the device with the abnormality using an indicator, and a power supplier that supplies power to the storage and the indication controller. The storage and the indication controller operate on power supplied from the power supplier. The power supplier supplies power from the main power supply unit when the power receiver receives power from the main power supply unit, and supplies power from the auxiliary power supply when the power receiver receives no power from the main power supply unit.