| 摘要 |
PURPOSE:To reduce maintenance and checking man-hour by controlling plural control subject devices by one unit in terms of time division, selecting a closed loop control and opened loop control and sharing a positioner. CONSTITUTION:An input signal from the control side through a transmission line 1 (11-1n) is selected by an input multiplexer 2 and given to a control pat 3 composed of a processor, memory, etc. A control signal from the control part 3 is selectively transmitted to a control valve 6 (61-6n) through an electropneumatic converter 4 and fluid multiplexer 5. A responding state detection means 7 (71-7n) is provided for the control valve 6. A detection signal from said means 7 is given to the control pat 3 through a detection multiplexer 8 and selector 9, and a detection signal of a pressure sensor 10 at the output side is given in the same manner. Thus the control part controls respective multiplexers 2, 5 and 8, switches the control from closed loop control to opened loop control if necessary, obtains the difference between a set value and observed one and transmits the control signal whose set and observed values are equal. |
