DUPLEX SYSTEM SWITCHING SYSTEM

摘要

PURPOSE:To easily cope even with the dynamic change of a process state by transferring the diagnosis signal for the diagnosis of a primary system in addition to a normal control signal and using the diagnosis signal to attain the quick and accurate diagnosis of troubles of the primary system. CONSTITUTION:The host controller 3A of the primary system performs a process control arithmetic and also produces a synchronizing signal 21. Then the controller 3A produces a test pattern signal 20 based on the signal 21 and transmits it to a standby mode host controller 3B as well as to a duplex system switching device 4 together with the control signal serving as the control arithmetic result as the transmission data. Both the controller 3B and the device 4 receive the transmission data from the controller 3A and produce test pattern signals 22 and 23 through the internal arithmetic and in the same system as the controller 3A based on the signal 21 contained in the received transmission data. Then the deviations delta1 and delta2 from the signal 20 of the primary system are monitored. Thus the abnormality of the primary system is decided when both deviations exceed the abnormality deciding level of the primary system set previously.