| 摘要 |
PURPOSE:To detect indicating a presence of disconnection, detachment of wiring, etc. in the load circuit, by operating a logical judgement for the output, from a current detector circuit for detecting a flow of current in the load circuit, and the output command. CONSTITUTION:With an output command of the sequencer applied to a terminal 1, a photothyristor 6 comes to be turned on. In case of the load circuit being in a normal state, AC current is fed to a load 10 from AC line 11 with the load 10 working. Simultaneously with the above, though a voltage across both ends of a Zener diode 8, 8' is applied to an exclusive ''or'' 19 through a photocoupler 16, a light emitting diode 21 does not emit a light because of both inputs to the exclusive ''or'' 19 being agreed. In case of a fault like disconnections in the load circuit, even for the output command to be applied to the terminal 1, no generation of voltage across the both ends of the Zener diode 8, 8' causes the exclusive ''or'' 19 to produce an output with the light emitting diode 21 made emitting a light. |
