| 摘要 |
PURPOSE:To assuredly prevent the malfunction of a controller caused by a fault of a DC power source, by detecting the output voltage of plural DC power sources of the controller and then controlling the output signal of the controller. CONSTITUTION:The output voltage of each of DC power sources 2-4 of a controller 5 is detected by a detecting circuit consisting of Zener diodes 7-9 plus photocouplers 10-12. A power source 13 at the output part of the controller 5 is used for the above-mentioned detecting circuit. The detected current of each photocoupler is converted into a voltage signal through resistances 14-16 to be supplied to an OR circuit 20 via inverters 17-19. Accordingly if at least a faulty voltage is detected, an auxiliary relay 21 is energized by the output of the circuit 20. As a result, the control signals supplied from auxiliary relays 231-23n of the control circuit 5 are locked to prevent the malfunction of the controller which is caused by a fault of the DC power source. |
