| 摘要 |
PURPOSE:To obtain a safety and protecting device of a plant with high reliabil ity by adding a circuit checking the input state so as to interlock the driving of a protected device. CONSTITUTION:Input relays 1-3 are provided with protection circuit contacts 1a-3a and check circuit contacts 1b-3b, and when any of said contacts 1b-3b is turned on by input state check circuits 11, 12 protective operation request signal is transmitted to a coil drive circuit 13. The drive circuit 13 as an OR function and a drive function similarly as a coil drive circuit 8 and when said protective operation request signal is received, the transmission of an exciting current to an UV coil 9 is stopped. If a fault takes place in a process of an atomic reactor for example, and the input relays 1,2 are deenergized, the contacts 1a,2a are opened, the 2/3 logic of the logic circwit 4 is established, the UV coil 9 is deenergized to trip an atomic reactor interrwptor. |
