| 摘要 |
PURPOSE:To simply test the safety from the photocoupler to the parent portion indicating light by turning ON and OFF the photocoupler of the slave portion display input portion by the test signal of ON and OFF from the parent portion device. CONSTITUTION:In accordance with the operation of ON test switch in the parent portion, when the test signal 31 is transmitted from the parent portion, AND gate 33 is brought into low level and the photocoupler 35 is turned ON. Thus, the displaying photocouplers 23-1 to 23-10 are all turned ON and the signals of the data bus 4 are transferred as low level signals to the parent portion. When from the parent portion, OFF test signal 32 is transmitted, AND gate 34 becomes high level and photocoupler 36 is turned OFF and the displaying input photo coupler 23-1 to 23-10 are all turned OFF and the signals of the data bus 4 are all transmitted to the parent portion as high level signals. |
