JPH062402U - Cascade controller - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to realize a cascade control device in which followability of a control target to a main control unit and a slave control unit is good. [Arrangement] The present apparatus inputs a set value and a measured value of a main control factor of a process, generates a manipulation output by performing a control calculation on a deviation between these inputs, and a main control unit. Input the operation output generated by the control unit as a set value, input the measured value of the control factor that is the slave of the process, and generate the operation output by performing the control calculation on the deviation of these inputs, and the slave control unit. Cascade control, comprising: an operation output of the control unit and an operation output of the main control unit; and a correction unit that generates an operation output for controlling the process in which a correction calculation is performed on these inputs. It is a device.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to improvement of control characteristics of a cascade control device that controls a process having a main control factor and a subordinate control factor by using a multistage loop.

[0002]

[Prior art]

 FIG. 3 shows a conventional cascade control device. In the figure, 1 is a process to be controlled, and 2 is a process affecting the process 1. 3 is a main control unit, which is a set value SV₁And the measured value PV of the main control factor of Process 1₁Operation output MV by inputting and, and applying the control calculation to the deviation of these inputs₁To occur. Reference numeral 4 denotes a sub-control unit, which is an operation output MV generated by the main control unit 3.₁Set value SV₂And the measured value PV of the control factor that is the slave of process 1₂Is input, and the operation output is generated by applying the control calculation to the deviation of these inputs. Reference numeral 5 is a control unit, which is a measured value PV of the process 2.₃And operation output MV₂Set value SV ₃ And outputs the operation output MV obtained by subjecting the deviation to a control calculation to control the process 2.

[0003]

[Problems to be solved by the device]

 In such a configuration, the main control unit controls the process via the slave control unit, so the control target can follow the slave control unit, but the control target follows the main computing unit. There was a problem that it was bad.

An object of the present invention is to realize a cascade control device that is excellent in both followability of a control target with respect to a main control unit and a slave control unit.

[0005]

[Means for Solving the Problems]

 The present invention, in a cascade control device for controlling a process including a main control factor and a subordinate control factor by a multistage loop, inputs a set value and a measured value of the main control factor of the process. Then, the main control unit that generates an operation output by performing a control calculation on the deviation of these inputs and the operation output generated by this main control unit are input as a set value, and the control factors that are subordinate to the process are input. Of the sub-control unit, which inputs the measured value of the sub-control unit and generates an operation output by performing a control calculation on the deviation of these inputs, the operation output of the sub-control unit, and the operation output of the main control unit. Correction means for generating an operation output for controlling the process in which the input is corrected.

[0006]

[Action]

 In the present invention as described above, by providing the correction means, it is possible to improve the followability of the controlled object with respect to the main controller.

[0007]

【Example】

The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. The same parts as those in FIG. 3 are designated by the same reference numerals. In FIG, 6 is a correcting means generates an operation output MV ₂ of the slave control unit 4 inputs the operation output MV ₁ of the main control unit 3, the operation output MV ₃ which has been subjected to correction operation on the input To do. The control unit 5 inputs the measured value PV ₃ of the process 2 and the operation output MV ₃ as the set value S V ₃ , outputs the operation output MV obtained by subjecting the deviation to the control calculation, and controls the process 2.

The correction calculation of the correction means 6 is performed as follows. Let MV ₃ = MV ₃ ′ + KΔMV ₁ + ΔMV ₂ . Here, MV ₃ 'is the previous output of the operation output MV ₃ , K is the proportional gain, ΔMV ₁ is the difference between the previous output of the operation output MV ₁ and this output, and ΔMV ₂ is the operation output MV. It is the difference between the previous output and the current output of ₂ .

The operation of such a device will be described below. FIG. 2 is a time chart of the apparatus shown in FIG. In the figure, (i) is the measured value PV ₁ , (ii) is the measured value PV ₂ , (iii) is the operation output MV ′ of the conventional cascade control device, and (iv) is the operation value of the device of FIG. 1. The output MV. When the measured value PV ₁ changes at the time point a, the conventional operation output MV ′ changes gently. On the other hand, when the present invention is applied, the operation output MV changes immediately following the change in the measured value PV ₁ . At the time point of b, when the measured value PV ₂ changes, both the conventional operation output MV ′ and the operation output MV change following the measured value PV ₂ .

Although the embodiment includes the control unit, the configuration may not include the control unit.

[0011]

[Effect of device]

 According to the present invention, there is an effect that the followability of the controlled object to the main control unit can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a time chart of the device of FIG.

FIG. 3 is a configuration diagram of a conventional cascade control device.

[Explanation of symbols]

 3 main control section 4 slave control section 6 correction means

Claims (1)

[Scope of utility model registration request] 1. In a cascade control device for controlling a process including a main control factor and a subordinate control factor by a multistage loop, a set value and a measured value of the main control factor of the process are set. A main control unit that generates an operation output by inputting a control calculation to the deviation of these inputs and an operation output generated by this main control unit as a set value, and controls the slave control factors of the process. A measured value is input, a sub-control unit that generates an operation output by performing a control calculation on the deviation of these inputs, an operation output of the sub-control unit, and an operation output of the main control unit are input, and these And a correction means for generating an operation output for controlling the process in which a correction calculation is applied to an input, and a cascade control device.