JP2576455B2 - Controller and control system using the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to, for example, a controller such as a temperature controller and a control system using the controller. More specifically, the present invention relates to a controller using a valve as an actuator and a controller using the same. It relates to the control system used.

(Prior Art) As this type of control system, for example, there is a temperature control system as shown in FIG.

In the figure, reference numeral 1 denotes a control target such as a heating furnace, 2 denotes an electric valve provided in a flow path of fuel or steam supplied to the control target 1, and 3 denotes a drive valve for driving the electric valve 2 to increase an opening degree. control modulates trawl motor as a motor for valve drive, 4 ₀ as the state value input from the temperature sensor 5 provided in the opening feedback resistor input and the controlled object 1 corresponding to the valve opening from the module trawl motor 3 This is a temperature controller that provides a control output so that the temperature of the control target 1 becomes the target temperature based on the temperature input described above, and performs control by a so-called position proportional control method.

(Problems to be Solved by the Invention) In the conventional control system using the position proportional control method using the opening feedback resistance input, the opening feedback resistance is abnormal due to disconnection or short circuit of the opening feedback resistance. In such a case, there is a risk that control may be lost.

The present invention has been made in view of the above points,
It is an object of the present invention to provide a regulator and a control system using the same, which have improved safety and reliability without causing control failure even when an abnormality occurs in the opening feedback resistance input.

(Means for Solving the Problems) In order to achieve the above object, the present invention is configured as follows.

That is, the controller of the present invention is a controller that performs a control operation on the motor in accordance with a position proportional control method using an opening feedback resistance input corresponding to a valve opening from a valve driving motor, wherein the opening feedback resistor When there is an abnormality in the input, the position proportional control method is switched to the floating control method that does not use the abnormal opening feedback resistance input, and the control operation for the motor is performed according to the floating control method.

Further, the control system of the present invention is based on a valve, a valve driving motor for controlling the opening of the valve, an opening feedback resistance input corresponding to the opening of the valve, and a state value input of the controlled object. A control system for providing a control output for the opening degree control to the motor in accordance with a position proportional control method to adjust a state of a control target.
The controller, when there is an abnormality in the opening feedback resistance input, switching from a control operation in the position proportional control method to a control operation in a floating control method that does not use the abnormal opening feedback resistance input. Features.

(Operation) According to the above configuration, disconnection or short circuit of the opening feedback resistor, etc.
If there is an error in the feedback resistance input from the motor to the controller, the system switches from the position proportional control method to the floating control method that does not use the abnormal opening feedback resistance input. In such a case, there is no loss of control.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of one embodiment of the present invention, and portions corresponding to the conventional example in FIG. 4 are denoted by the same reference numerals.

In the figure, 1 is a controlled object such as a heating furnace, 2 is an electric valve provided in a flow path of fuel or steam supplied to the controlled object 1, and 3 is an electric valve that drives the electric valve 2 to open. A mod roll motor as a valve driving motor to be controlled is controlled by an opening feedback resistance input corresponding to the valve opening from the mod roll motor 3 and a temperature as a state value input from a temperature sensor 5 provided on the control target 1. This is a temperature controller that performs control by a position proportional control method by providing a control output to the mod-roll motor 3 so that the temperature of the control target 1 becomes the target temperature based on the input.

In this embodiment, when an abnormality occurs in the input of the opening feedback resistor due to disconnection or short circuit of the opening feedback resistor, etc., the temperature controller 4 includes:
Detecting means for detecting an abnormality of the opening feedback resistance input, and when the detecting means determines that an abnormality has occurred in the opening feedback resistance input, the position proportional control method does not use the abnormal opening feedback resistance input. A microcomputer as control means for controlling the motor by switching to the floating control method. After the microcomputer switches to the floating control method, the microcomputer controls the temperature of the control target 1 based on a temperature input from the temperature sensor 5. A control operation of giving a control output to the mod-roll motor 3 so as to reach the target temperature is performed.

That is, in this embodiment, when the value of the opening feedback resistor input becomes an abnormal value (infinity, 0) corresponding to a disconnection, a short circuit, or the like, the temperature controller 4 constituted by a microcomputer or the like returns the opening feedback. Judge that the resistance input is abnormal and LED
An alarm signal is output to an alarm means 6 such as a buzzer or the like, and an alarm is issued. In addition, the position proportional control method using the opening feedback resistance input is switched to the floating control method using no opening feedback resistance input.

FIG. 2 is a control flowchart of the temperature controller 4.

First, in step n1, the temperature input from the temperature sensor 5 provided in the control
Then, the input of the opening degree feedback resistance from is taken in, and the process proceeds to step n2. In step n2, similarly to the conventional system, it is determined whether or not the temperature input is within a predetermined allowable range, and if not, it is determined that the temperature of the control target 1 is abnormal. Move to n8 to perform alarm processing.

In Step n2, when the temperature input is within the allowable range, the process proceeds to Step n3, and a process for determining whether there is an abnormality in the opening feedback resistance input is started.

In step n3, it is determined whether or not the opening feedback resistor is disconnected based on the value of the opening feedback resistor input.If the opening feedback resistor is disconnected, the process proceeds to step n6.If not, step n4 is performed. To determine whether there is an abnormality other than the disconnection such as a short circuit.
Then, it is determined that there is an abnormality in the opening feedback resistance input, an alarm process is performed, and the process proceeds to Step n7. In Step n4, when there is no abnormality, the process proceeds to Step n5.

In step n5, based on the opening feedback resistance input, the temperature input and the target temperature, a control output amount for the mod roll motor 3 is calculated in accordance with the position proportional control method,
The output is output to the mod roll motor 3 and the process returns to step n1.

In step n7, since there is an abnormality in the opening feedback resistance input, switching from the position proportional control method to the floating control method not using the abnormal opening feedback resistance input is performed,
Based on the temperature input and the target temperature, a control output amount for the mod roll motor 3 is calculated in accordance with the floating control method, output to the mod roll motor 3, and the process returns to step n1.

When an abnormality occurs in the opening feedback resistance input as described above, the control is switched to the floating control method that does not use the abnormal opening feedback resistance input, and the control operation for the mod roll motor 3 is performed. There is no impossibility.

Further, according to the control system of the present invention, one temperature controller 4 can cope with any electric valve with or without the opening feedback resistor. Further, in this embodiment, since the abnormality of the opening feedback resistance input is notified by the alarm means 6, it is possible to take immediate action.

In this embodiment, in the control by the floating control method, the control output amount for the mod roll motor 3 is calculated. However, in another embodiment of the present invention, the control output amount for the input to the memory is calculated without performing the calculation. May be stored, and the control output amount may be read from this data.

Further, as another embodiment of the present invention, for example, as shown in FIG. 3, a disconnection detecting section 8 of a feedback resistor 7 is provided in a feedback resistance input circuit to detect the presence or absence of a disconnection or the like. You may. In FIG. 3, reference numeral 9 denotes an input circuit, 10 denotes an A / D conversion circuit, and 11 denotes a CPU constituting the temperature controller 4.
It is.

Further, as another embodiment of the present invention, in addition to the above-described function of detecting an abnormality of the opening feedback resistance input and switching the control method, an abnormality of the mod-roll motor 3 is detected as follows and an alarm is issued. It may be possible to emit.

That is, in a state where there is no abnormality in the opening feedback resistance input, the absolute value of the difference between the control output change amount for the mod-roll motor 3 and the actual opening change amount of the electric valve 2 based on the opening feedback resistance input. Is greater than or equal to a predetermined reference value, it is determined that there is an abnormality in the mod-roll motor 3.

For example, the amount of change ΔRMV of the control output for the mod roll motor 3 is calculated according to the following equation: ΔRMV = RMV (n) −RMV (n−1) where RMV (n): the mod roll motor 3 at time n (this time). RMV (n-1): Control output amount for the mod-roll motor 3 at time n-1 (previous time) Further, a change amount .DELTA.OP of the valve opening based on the opening feedback resistance input is calculated according to the following equation. ΔOP = OP (n) −OP (n−1) where OP (n): opening of the electric valve 2 based on the opening feedback resistance input at time n (this time) OP (n−1): time n−1 The opening degree of the motor-operated valve 2 based on the opening feedback resistance input in the previous time. Further, the absolute value of the difference between the control output change amount ΔRMV for the mod-roll motor 3 and the valve opening change amount ΔOP based on the opening feedback resistance input. Calculate the value | ΔRMV−ΔOP | Then, it is determined whether or not this absolute value is equal to or greater than a predetermined reference value for determining whether there is an abnormality in the motor control motor 3, and when the absolute value | ΔRMV−ΔOP | is equal to or greater than the reference value. That is, the alarm processing is performed on the assumption that the opening degree of the electric valve 2 is not changed in response to the control output, that is, the abnormality of the mod-roll motor 3.

By adding such a function of detecting an abnormality of the mod roll motor 3, the
Can be detected at an early stage, and the reliability of the system can be further improved.

(Effects of the Invention) As described above, according to the present invention, the controller controls the motor in accordance with the position proportional control method using the opening feedback resistance input corresponding to the valve opening from the valve driving motor. During the operation, if there is an abnormality in the opening feedback resistance input, the control operation for the motor can be performed by switching from the position proportional control method to the floating control method not using the abnormal opening feedback resistance input. Therefore, in a control system using this, when an abnormality occurs in the opening feedback resistance input as in the related art, control is not lost, and the safety and reliability of the system are improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of one embodiment of the present invention, FIG. 2 is a flowchart for explaining the operation, FIG. 3 is a block diagram of a feedback resistor input circuit of another embodiment of the present invention, and FIG. It is a schematic structure figure of an example. DESCRIPTION OF SYMBOLS 1 ... Control target, 2 ... Electric valve, 3 ... Mod roll motor (valve drive motor), 4 ... Temperature controller, 6 ... Alarm means, 8 ... Disconnection detection part.

Continuation of the front page (56) References JP-A-52-37683 (JP, A) JP-A-54-72419 (JP, A) JP-A-55-28109 (JP, A) , U) Japanese Utility Model Showa 62-160708 (JP, U)

Claims (2)

(57) [Claims] A controller for controlling the motor in accordance with a position proportional control method using an opening feedback resistance input corresponding to a valve opening from a valve driving motor, wherein the opening feedback resistance input is abnormal. When there is, the controller switches from the position proportional control method to a floating control method that does not use the abnormal opening feedback resistance input, and performs a control operation on the motor according to the floating control method. 2. A position proportional control method based on a valve, a valve driving motor for controlling the opening of the valve, an opening feedback resistance input corresponding to the opening of the valve, and a state value input of a controlled object. A controller for providing a control output for the opening control to the motor in accordance with to adjust the state of the control target. A control system for switching from a control operation using the position proportional control method to a control operation using a floating control method that does not use the abnormal opening feedback resistance input.