| 摘要 |
PURPOSE:To reduce the load of the CPU by controlling a process based on the signal obtained by applying D/A conversion to the output of an up-down counter when a main CPU has a trouble. CONSTITUTION:When a main CPU 1 has a trouble, an output is outputted from a trouble monitor part 16 together with a signal A outputted from an OR circuit 17. While an auto/manual switch 19 is changed to a manual side. Thus the data set at an up-down counter 4 is manually changed and a process 8 is manually controlled. At the same time, the output signal of the part 16 is also supplied to a digital display CRT 15 and the digital displays PV, SV and MV of a digital display device 14 are erased. The signal A is also supplied to a secondary CPU 9 when the CPU 1 has a trouble. The CPU 9 uses the data on the measured value PV and the manipulated variable MV of the process 8 supplied via an A/D converter 9a to actuate a bar display device for display of bars. In such a way, the load of the CPU 1 is reduced.
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