JPH03118602A - Controller - Google Patents

Abstract

PURPOSE:To secure a control mode of a deviation differential type during the control by inputting selectively the value obtained by differentiating the set value on the basis of an input differentiation type controller to an internal totalization part of an integral arithmetic part via a switch. CONSTITUTION:A switch 14 is kept ON for a short time at time T1 and therefore the value related to the change rate of the value SP set at that time is inputted to a totalization part 12. Thus the value DSP increases by that input value. Then the switch 14 is shortly turned off but the value DSP set at the time T1 is maintained owing to the totalization of the part 12. The switch 14 is turned on again at time T2 and kept as it is for a short time. Under such conditions, the value SP is reduced and therefore the value DSP is also reduced by a fixed degree and kept as it is. Then the differential value of the value SP set at that time can be fetched to the operation of the manipulated variable MV. The value DSP is related to the differential value of the value SP. Meanwhile only the process value PV is inputted to a 2nd differential arithmetic part 16. As a result, the variable MV is approximately computed based on the differential value of (SP - PV).

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an improvement in a controller that calculates a manipulated variable from a process variable and a set value and outputs it to the process.

<Prior art> Figure 4 (A) shows the configuration of a micro-type controller, and Figure 4 (B) shows the configuration of a micro-type controller.
, (C) shows its characteristics. In FIG. 4 (A), the set value SP and the process amount P■ are input to the differential input unit 1,
The deviation is calculated. This deviation is input to an integral calculation section 2, a proportional calculation section 3, and a differential calculation section 4, where integral, proportional, and differential calculations are performed, respectively. The integral calculation unit 2 includes an accumulation unit 5, and the accumulation unit 5 executes the integral calculation. The outputs of these integral, proportional, and differential calculation units 2 to 4 are added by an addition unit 6 and output to the process as a manipulated variable MV. (B) is the setting (di S P and the manipulated variable MV
The differential value of the set value SP that affects the -6 positive value in the section where the set value SP increases, which is schematically expressed,
It becomes a negative value in the decreasing section.

That is, since the deviation between the set value SP and the process amount PV is input to the differential calculation section 4, the differential value of the set value SP is determined by the operation i.
Affects MV. (C) shows an example of control. In ramp control where the set value SP increases at a constant rate, the followability of the process amount P■ to the set value SP is relatively good, and the manipulated variable MV only decreases when the set value SP reaches a constant value. , an overshoot occurs in the process amount Pv.

FIG. 5 shows an example of an input differential type controller. (
As shown in A), in the input differential type controller, the differential calculation section 4
Input the process iP■ itself. In addition, the calculation section 7
At , (output of the output differential calculation section of the output child proportional calculation section of the integral calculation section) is calculated to obtain the manipulated variable MV.

Since the component of the set value SP is not input to the differential calculation section 4,
8. The set value SP changes as shown in (B). It remains a bulge. An example of control is shown in (C), but the followability of the process amount P■ to the set value SP in lamp control is inferior to that of the deviation differential type controller shown in FIG. Further, overshoot 1 occurs in the process amount PV. Conventionally, these controllers were used depending on the characteristics of the process.

<Problems to be Solved by the Invention> However, even in one process, there are cases where the deviation differential type is suitable and cases where the input differential type is suitable.

In such a case, if two types of controllers are prepared and switched in the middle of control, the manipulated variable MV will bump at the time of switching, resulting in a loss of continuity of control.

<Object of the Invention> An object of the present invention is to provide a controller that can add a deviation differential type adjustment mode to an input differential type controller as necessary.

Means for Solving the Problems> In order to solve the above problems, the present invention provides a first differential calculation section into which a set value is input, a second differential calculation section into which a process amount is input, and a second differential calculation section into which a set value is input. and the outputs of the proportional calculation section and the integral calculation section into which the deviation of the process amount is input, and the outputs of the integral calculation section and the proportional calculation section, and the output of the second differential calculation section are added to [3Ll, and the lever calculation result is It has a calculation section that outputs the output to the process as a manipulated variable, and the output of the first differential calculation section is selectively inputted to the accumulation section in the integral calculation section via a switch.

Effect> By adding the outputs of the first differential operation section in the accumulating section, it is possible to temporarily enter the deviation differential adjustment mode.

<Example> FIG. 1 shows an embodiment of a controller according to the present invention.

Note that the same elements as in FIG. 5 are designated by the same reference numerals, and their explanations will be omitted. In FIG. 1, reference numeral 10 denotes a first differential calculation section, which receives a set value SP and outputs its differential value. 1
Reference numeral 1 denotes an integral calculation section, which includes an accumulation section 12 therein. The accumulator 12 performs accumulation (integration) by adding the output of the arithmetic unit 13 and its own output. 14 is a switch which converts the output of the first differential calculation unit 10 to the accumulator 1.
Controls whether or not to input to 4. Reference numeral 15 denotes a supervisor, to which the process amount P■, set value SP, etc. are input (not shown), and controls opening and closing of the switch 14. For example, at the beginning when the set value SP changes at a constant rate, switch 1
Turn on 4. The rule for when to turn on the switch 14 can be arbitrarily selected. 16
2 is a second differential calculation section, which receives the process amount P■ and calculates and outputs the differential value thereof. The output of the deviation calculation section 1, that is, the deviation between the set value SP and the process amount P■ is input to the integral calculation section 11 and the proportional calculation section 3. Further, the calculation unit 7 executes the calculation (output of the integral calculation unit + output of the proportional calculation unit, output of the second differential calculation unit), and outputs it to the process as the manipulated variable MV.

Next, the operation of the embodiment shown in FIG. 1 will be explained based on FIG. FIG. 2 shows the change in the set value SP and the change in D, which is the degree of influence that the change in the set value SP has on the manipulated variable MV. 0 time T1
Since the switch 14 is turned on for a short time at D8., a value related to the rate of change of the set value SP at that time is input to the accumulator 12, and D8. increases by its value. Although the switch 14 is turned off immediately, D 2 maintains the p 2 value at time T1 as a result of the accumulation in the accumulator 12. At time 'r2, switch 14 is turned on again for a short time. At this time, since the set value SP is decreasing, DSp decreases by a constant value and maintains that value. In this manner, by turning on the switch 14, the differential value of the set value SP at that time can be incorporated into the calculation of the operation iMV. D3. is related to the differential value of the set value SP, and on the other hand, only the process variable PV is input to the second calculation unit 16, so the manipulated variable MV is approximately expressed as (set value sp - process variable PV). It will be calculated using differential values. In other words, the mode becomes a deviation differential type adjustment mode. Furthermore, since it is input to the accumulator 12, the differential value of the set value SP at the time of switch-on is held even after the switch 14 is turned off. Therefore, by changing the switch-on time, the degree of open-radical differential mode can be changed.

FIG. 3 shows an example of control. This diagram shows changes in set value SP, process amount PV and manipulated variable MV, and supervisor 15
Represents the flag held by . When the set value SP starts increasing, the flag becomes -1.

This flag -1 indicates that the process amount Pv does not follow the set value SP. The supervisor 15 turns on the switch 14 for a short time the first time this flag becomes -1. Therefore, the above-mentioned D increases by p and the mode becomes approximately the deviation differential type adjustment mode, so the followability of the process amount P■ to the set value SP is as shown in Fig. 4 (
It is equivalent to the deviation differential type controller shown in C). Note that in this operation example, the flag is set to 2 before the set value SP reaches a constant value, and the manipulated variable MV is decreased in advance to prevent overshoot of the process variable Pv, but this is not directly related to this invention. There is no relationship. However, since an operation that reduces the manipulated variable MV in advance becomes a disturbance element, the input differential type is more suitable than the deviation differential type.

Since the present invention is based on the input differential type adjustment mode,
This is convenient in cases like this.

<Effects of the Invention> As described above in detail based on the embodiments, the present invention is based on an input differential type controller, and selectively differentiates the set value into the integral calculation section through the switch. It is now entered into the cumulative section. Therefore, it is possible to realize a deviation differential type adjustment mode during control, and there is an effect that the process amount can be made to follow a rapid change in the set value without causing a bump in the manipulated variable.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a controller according to the present invention;
FIGS. 2 and 3 are characteristic curve diagrams for explaining its operation, and FIGS. 4 and 5 are diagrams showing the configuration of a conventional controller and its operating characteristics. 3... Proportional calculation section, 10... First differential calculation section, 1
DESCRIPTION OF SYMBOLS 1... Integral calculation part, 12... Accumulation part, 14... Switch, ] 5... Supervisor, 6... Second differential calculation part. No.! Figure Figure ν Busy J? J

Claims (1)

[Claims] A first differential calculation section receives a set value, calculates and outputs a differential value of the set value, and receives a deviation between the set value and the process amount, and calculates this deviation proportionally. There is a proportional calculation section that outputs an output, an integral calculation section that inputs the deviation between the set value and the process amount, performs integral calculations on this deviation, and outputs it. A second differential calculation section that differentially calculates a quantity and outputs it; and the outputs of the integral calculation section and the proportional calculation section are added together, and the output of the second differential calculation section is subtracted, and the calculation result is manipulated. 1. A controller comprising: a calculation section that outputs a quantity to a process; and an output of the first differential calculation section is selectively input to the accumulation section via a switch.