JP4771227B2 - Electro-pneumatic positioner operating speed controller - Google Patents

Description

The present invention relates to an apparatus for controlling the operating speed of an electropneumatic positioner.

Conventionally, as one of the electropneumatic positioners, in order to control the valve opening of the regulating valve according to the input signal, a position sensor that detects a lift position corresponding to the valve opening of the regulating valve, the input signal, and the A control unit that generates a control signal for controlling the valve opening from a detection signal of a position sensor; an electropneumatic conversion unit that generates a pneumatic signal corresponding to the control signal from the control unit and sends the pneumatic signal to the adjustment valve; There is something with.
JP 7-269505 A

However, in the conventional electropneumatic positioner configured in this way, when the actuator control amount is significantly changed based on the PID control signal, the adjustment valve is actuated sharply and greatly, and the adjustment valve is punched. There was a problem of causing damage and causing overshoot.

The present invention has been made in view of the above circumstances, and an object thereof is to prevent the adjustment valve from being actuated sharply and greatly even when the actuator control amount is significantly changed based on the PID control signal. Another object of the present invention is to provide an electro-pneumatic positioner operating speed control device that can improve convergence to a target value.

In order to solve the above problem, the electropneumatic positioner operating speed control device according to the present invention is a device for controlling the operating speed of the electropneumatic positioner; calculated by PID calculation or the like and output from the control amount command unit Data for comparing and determining the digital value d1 of the actuator control amount by the electro-pneumatic positioner and the digital value d2 of the actuator control amount previously calculated as the actuator control amount by the electro-pneumatic positioner and output from the apparatus A comparison unit; an operation speed setting clock oscillation unit that oscillates a clock that is turned on at every set value interval of the timer unit and changes the operation speed of the electropneumatic positioner by changing the set value; The clock oscillated from the part is turned ON and the digital value d1 is larger than the digital value d2. An addition command switch that is turned on in this case; a data addition unit that adds a constant “1” to the digital value d2 when the addition command switch is turned on; a clock oscillated from the operating speed setting clock oscillation unit; A subtraction command switch that is turned on when the digital value d1 is smaller than the digital value d2, and a data subtraction unit that subtracts a constant “1” from the digital value d2 when the subtraction command switch is turned on; An output data selection switch that adds or subtracts a constant “1” based on an output signal from the data adder or the data subtractor to update and output the digital value d2.

In this configuration, when the electropneumatic positioner system is driven after the interval at which the timer of the operating speed setting clock oscillation unit is turned ON is set in the operating speed setting clock oscillation unit in advance, it is calculated by PID calculation or the like. The digital value d1 of the actuator control amount by the electro-pneumatic positioner output from the control amount command unit is input to the data comparison unit, and is calculated in advance as the actuator control amount by the electro-pneumatic positioner to perform the main operation speed control. The digital value d2 of the actuator control amount output from the apparatus is input to the data comparison unit, and the data comparison unit compares these two digital values d1 and d2.

When the clock oscillated from the operating speed setting clock oscillating unit is turned ON and the digital comparison result of the two digital values d1 and d2 by the data comparison unit is greater than the digital value d2, an addition command The switch is turned ON, the data adding unit adds a constant “1” to the digital value d2, and the output data selection switch outputs the added digital value as an updated value. Thereafter, the data comparison unit compares the updated value with the digital value d1 again, and the above addition operation is repeated until the updated value becomes larger than or equal to the digital value d1.

Similarly, when the clock oscillated from the operating speed setting clock oscillation unit is turned ON and the digital value d1 is smaller than the digital value d2 as a result of comparison between the two digital values d1 and d2 by the data comparison unit, subtraction is performed. The command switch is turned ON, the data subtracting unit subtracts a constant “1” from the digital value d2, and the output data selection switch outputs the subtracted digital value as an update value. Thereafter, the data comparison unit compares the update value with the digital value d1 again, and the above subtraction operation is repeated until the update value becomes smaller than or equal to the digital value d1.

When the updated value thus output matches the digital value d1, the updated value is converted from a digital value to an analog value by the digital / analog converter and transmitted to the electropneumatic positioner.

As is apparent from the above description, the present invention is an apparatus for controlling the operating speed of an electropneumatic positioner; an actuator control amount by the electropneumatic positioner calculated by a PID calculation or the like and output from a control amount command unit A data comparison section for comparing and comparing the digital value d1 of the actuator and the digital value d2 of the actuator control amount calculated in advance as an actuator control amount by the electropneumatic positioner and output from the apparatus; An operating speed setting clock oscillator that oscillates a clock that varies the operating speed of the electropneumatic positioner by changing the set value; and the clock oscillated from the operating speed setting clock oscillator is turned ON. And an addition command switch that is turned on when the digital value d1 is greater than the digital value d2. A data adder that adds a constant “1” to the digital value d2 when the addition command switch of the switch is turned ON; the clock oscillated from the operating speed setting clock oscillator is turned ON, and the digital value d1 is the digital value A subtraction command switch that is turned on when the value is smaller than the value d2, a data subtraction unit that subtracts a constant "1" from the digital value d2 when the subtraction command switch is turned on; the data addition unit or the data subtraction unit And an output data selection switch that updates or outputs the digital value d2 by adding or subtracting a constant "1" based on the output signal from the output signal from the operation speed control device. The actuator is converged and matched with the digital value d1 of the actuator control amount calculated from the control amount and output from the control amount command section. Because the control data is sent from the output data selection switch to the electropneumatic positioner, even if the actuator control amount is significantly changed based on the PID control signal, the adjustment valve is actuated sharply and greatly based on the PID control signal. It has excellent practical effects such as being able to prevent the above.

Next, an embodiment of an electropneumatic positioner system to which the present invention is applied will be described in detail with reference to FIGS. As shown in FIG. 1, the electropneumatic positioner system includes a control amount command unit 5 that calculates and outputs an actuator control amount by an electropneumatic positioner by PID calculation or the like, and a control amount from the control amount command unit 5. The operating speed control device 1 to be changed, the digital / analog converting portion 2 for converting the digital value after the operating speed control outputted from the operating speed control device 1 of the electropneumatic positioner into an analog value, and the digital / analog converting portion 2 is constituted by an electropneumatic positioner 3 that operates based on an analog value from 2, and a pneumatic control valve 4 as an actuator that is controlled by the output pressure from the electropneumatic positioner 3.

In the operating speed control device 1 for the electropneumatic positioner, the digital value d1 of the actuator control amount by the electropneumatic positioner 3 calculated by PID calculation or the like and output from the control amount commanding unit 5, and the electropneumatic positioner A data comparison unit 12 for comparing and comparing the actuator control amount digital value d2 calculated in advance as the actuator control amount by the positioner 3 and output from the operation speed control device 1; An operating speed setting clock oscillating unit 14 that oscillates a clock that changes the operating value of the electropneumatic positioner 3 by changing the set value; and the clock oscillated from the operating speed setting clock oscillating unit 14 is turned on. And when the digital value d1 is greater than the digital value d2, the addition command switch is turned on. A data adding unit 16 for adding a constant “1” to the digital value d2 when the addition command switch 15 is turned ON; and a clock oscillated from the operating speed setting clock oscillating unit 14 is turned ON. A subtraction command switch 17 that is turned on when the digital value d1 is smaller than the digital value d2, and a data subtracting unit 18 that subtracts a constant “1” from the digital value d2 when the subtraction command switch 17 is turned on. And an output data selection switch 19 that adds or subtracts a constant “1” based on an output signal from the data adder 16 or the data subtractor 17 to update and output the digital value d2.

In this configuration, when the system of the electropneumatic positioner is driven after the interval at which the timer unit 13 of the operation speed setting clock oscillation unit 14 is turned on is set in the operation speed setting clock oscillation unit 14 in advance, the PID calculation is performed. The digital value d1 of the actuator control amount by the electropneumatic positioner 3 calculated by the above and output from the control amount command unit 5 is input to the data comparison unit 12 and precedes as the actuator control amount by the electropneumatic positioner 3 The digital value d2 of the actuator control amount calculated and output from the operation speed control device 1 is input to the data comparison unit 12, and the data comparison unit 12 compares these two digital values d1 and d2.

When the clock oscillated from the operating speed setting clock oscillating unit 14 is turned on and the digital value d1 is larger than the digital value d2 as a result of the comparison of the two digital values d1 and d2 by the data comparing unit 12, The addition command switch 15 is turned on, the data adder 16 adds a constant “1” to the digital value d2, and the output data selection switch 19 outputs the added digital value as an update value. Thereafter, the data comparison unit 12 compares the updated value with the digital value d1 again, and the above addition operation is repeated until the updated value becomes larger than or equal to the digital value d1.

Similarly, when the clock oscillated from the operating speed setting clock oscillating unit 14 is turned ON and the digital value d1 is smaller than the digital value d2 as a result of the comparison of the two digital values d1 and d2 by the data comparing unit 12. The subtraction command switch 17 is turned ON, the data subtracting unit 18 subtracts a constant “1” from the digital value d2, and the output data selection switch 19 outputs the subtracted digital value as an update value. Thereafter, the data comparison unit 19 compares the updated value with the digital value d1 again, and the above subtraction operation is repeated until the updated value becomes smaller than or equal to the digital value d1.

In other words, when the digital value d1 of the actuator control amount output by the electropneumatic positioner 3 output from the control amount command unit 5 increases sharply, the updated value is stored in the operating speed setting clock oscillation unit 14 as shown in FIG. It is calculated by repeating the addition of a constant “1” until the set value of the timer unit 13 increases stepwise with an interval and matches the digital value d1. Even when the value decreases sharply, the update value decreases stepwise with the set value of the timer unit 13 in the operating speed setting clock oscillation unit 14 as an interval, and the constant “1” is subtracted until it matches the digital value d1. Is repeated to calculate. In this way, even when the digital value d1 of the actuator control amount output from the control amount command unit 11 is sharply and significantly changed, the update value for actually driving the electropneumatic positioner 3 is gradually changed, An excessive influence on the process value can be suppressed.

As shown in FIG. 1, a bypass switch 20 is provided between the operating speed control device 1 and the digital / analog conversion unit 2, and the bypass switch 20 is connected to the control amount command unit 11 and the data comparison unit. By making an electrical connection between the air pressure adjusting device 12 and the air pressure adjusting device 12, it is possible to bypass the operating speed control device 1 in an emergency and operate the pneumatic regulator 4 to the safe operating side at the shortest speed.

It is a block diagram which shows the structure of one Example of the system of the electropneumatic positioner to which this invention is applied. It is a graph which displays the image of the operating speed calculating part of the system of the electropneumatic positioner to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Operation speed control apparatus 5 Control amount instruction | command part 12 Data comparison part 13 Timer part 14 Operation speed setting clock oscillation part 15 Addition command switch 16 Data addition part 17 Subtraction command switch 18 Data subtraction part 19 Output data selection switch

Claims (1)

A device for controlling the operating speed of the electropneumatic positioner;
The digital value d1 of the actuator control amount by the electropneumatic positioner calculated by PID calculation or the like and output from the control amount command unit, and the actuator control amount by the electropneumatic positioner are calculated in advance and output from this apparatus. A data comparison unit for comparing and determining a digital value d2 of the actuator control amount;
An operating speed setting clock oscillating unit that oscillates a clock that is turned on every set value interval of the timer unit and changes the operating speed of the electropneumatic positioner by changing the set value;
An addition command switch that is turned on when the clock oscillated from the operating speed setting clock oscillation unit is turned on and the digital value d1 is larger than the digital value d2;
A data addition unit for adding a constant “1” to the digital value d2 when the addition command switch is turned ON;
A subtraction command switch that is turned on when the clock oscillated from the operating speed setting clock oscillation unit is turned on and the digital value d1 is smaller than the digital value d2;
A data subtraction unit for subtracting a constant “1” from the digital value d2 when the subtraction command switch is turned ON;
An output data selection switch for adding or subtracting a constant “1” based on an output signal from the data adding unit or the data subtracting unit to update and output the digital value d 2;
An operation speed control device for an electropneumatic positioner, comprising: