| 摘要 |
PURPOSE:To enable continuous change-over not causing chattering, by holding the output of main system at the digital output change-over from the main system to the waiting system and delaying the switching timing longer than the sampling period of computer. CONSTITUTION:The computer 1, digital input unit 2, CPU3 and digital output unit 4 are respectively constituted with the duplex system A, B, the output of the failure output units 12A, 12B is input to the switching discrimination circuit 10 to control the switching unit 6 via the timer 20. In this case, if failed output is given to the computer of the main system, the output of the computer of the main system stored for a longer period than the sampling period of the computer at least, is outputted as it is, and after the period is elapsed, the switching to the output of waiting system can be made. Thus, the continuous change-over not causing chattering to the output can be made. |
