| 摘要 |
PURPOSE:To detect the disconnection of an input converter easily by confirming the normalcy of circuit groups on the secondary side of the input converter, applying a power supply for monitor from the primary side and comparing a value after the application of voltage with a set value. CONSTITUTION:Voltage is applied to a power supply 1c for monitor by an auxiliary relay 2c, and input to the primary side of an input converter 4 to which voltage at the normal time is not applied. The normalcy of the secondary side (a filter circuit 5, a sample-and-hold circuit 6, a multiplexer circuit 7 and an A/D converter 8) of the input converter 4 is decided in an analog input circuit. Voltage for monitor is applied to a circuit 12, to which voltage at the normal time is not applied, from the primary side of the input converter 4 in addition to the decision. The normalcy of the input converter 4 is decided by comparing a value after the application of voltage with a preset value. Accordingly, trouble such as the disconnection of the circuit, to which voltage at the normal time is not applied, can be detected easily by the input converter 4. Reliability is improved because inspection is conducted from the secondary side. |
