| 摘要 |
PURPOSE:To control a main system and subordinate system by switching by discriminating the self-diagnostic function of a digital system from an abnormal system considering the deviation between both the systems by hybrid type double system controller. CONSTITUTION:The double system controller consisting of an analog system by analog controller 1 and a digital system by digital controller 2 allows the latter to generate signal 2b when an error is found through self-diagnosis. Both units 1 and 2 receive output (a) from a process system and the output 3a returns to the process system via switch 30. Outputs 1a and 2a are inputted to tieback circuits 5 and 6 to synchronize units 1 and 2. Deviation detection circuit 7 receives outputs 1a and 2a all the time and makes comparisons 8 with reference value R and either gate 10 or 12 operates depending upon which unit 1 or 2 is abnormal, so that switching control from unit 1 to unit 2 or reversely will be performed. |
