| 摘要 |
PURPOSE:To execute self diagnosis immune to erroneous transmission without increasing the load of a host station by adding a self diagnostic function according to an inversion test to the DI part of a slave station in a remote supervisory and controlling equipment. CONSTITUTION:In slave stations 13-19, comparator circuits 21 are provided to decide coincidence/noncoincidence between digital input signals 15 and inverted data inputted through inverter circuits 16, and decision circuits 20 are provided to decide compared results and to output inverting instructions, and at a host station 10, a self diagnosis processing part 22 is provided. Concerning the function tests of the DI parts in the slave stations 13-19, the host station 10 just only sends the inversion test instructions to the slave stations and receives the self diagnosed results according to the inversion tests, and contents to be transmitted between the host station and the slave station become the small amount of data. On the other hand, the inverted data are locked by the slave stations 13-19 and it is not necessary to execute an interlock processing at the host station 10. Thus, the self diagnosis can be made immune to the influence of noise in the middle of transmission and can be executed without applying the large load to a CPU 11 of the host station 10. |
