| 摘要 |
PURPOSE:To prevent disorder of a sent back signal to be transmitted to a main apparatus immediately after a relay is operated and improve reliability by installing a relay electric power source circuit electrically insulated from a transmitting cable and driving a double coil latching relay. CONSTITUTION:At normal time, a transmission signal is sent from a main operational board 1 through a transmission cable 2, a photo-transistor 34 of a control terminal device 3 corresponding to the address in data received by a transmission circuit 5 is turned on by the signal, and a double coil latching relay 41 is set on by a relay electric power source circuit 37 through a driving circuit 36 and a switch 42 is closed. In the case of abnormal transmission, a Zener diode 16 of a transmission abnormality detecting circuit 15 is turned off, a transistor 18 is turned off, and a transistor 10 of a fail safe drive circuit 6 is turned on. Due to this, the photo transistor 34 is turned on to turn the set of the relay 41 on and the switch 42 is closed. Consequently, a sent back signal to be transmitted to the main apparatus immediate after relay operation is prevented from being disordered and reliability is improved. |
