| 摘要 |
<p>In order to enable device data (371) to be reliably saved even if a voltage hold decreases due to deterioration of an electrolytic capacitor (22), a CPU (36) saves a portion of the device data (371) that is in device memory (37) in storage memory (33) for each scan process, and when a power failure detection circuit (24) detects a main power source power failure, the CPU (36) uses a power source (4d) maintained by the electrolytic capacitor (22) to save the remaining device data (37) in the device memory (37). In order to increase the amount of device data (371) that is to be saved for each scan process when a capacitance detection circuit (23) detects that the capacity of the electrolytic capacitor (22) has decreased, the CPU (36) changes the amount of device data to be saved by means of the save process for each scan process in response to the capacity of the electrolytic capacitor (22) detected by the capacitance detection circuit (23).</p> |
