JP3795439B2 - PID controller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a PID control device that facilitates and simplifies the setting of parameters for PID calculation used for PID control.
[0002]
[Prior art]
PID control is a control method that stabilizes a control value quickly to a target value by adjusting each element of P (proportional), I (integral), and D (derivative), and has a wide range of temperature, flow rate, positioning, etc. Used in the control field. Such PID control is difficult to be performed by a programmable logic controller (PLC), and is generally performed by a PID unit which is a dedicated regulator. The PID unit is connected to the PLC, receives a control command from the PLC, performs PID calculation so that the control output becomes a set control value, and transmits the measured value to the PLC.
[0003]
The above control command can be input by a control display device such as a programmable display provided as a host device of the PLC. The control display device can also display the measurement values transmitted from the PLC. Hereinafter, the description of the control display device will be described as an example of a programmable display.
[0004]
Programmable displays are equipped with I / O that can directly connect devices without going through a PLC, and a model having a control function equivalent to a PLC has appeared. Such a programmable display device can directly exchange control commands and data with the PID unit by directly connecting a PID unit such as a temperature controller.
[0005]
In order to control the PID unit by a programmable display, various parameters necessary for the control cannot be directly input from the programmable display. In such a case, parameters are input using an editor for parameter setting installed in a personal computer (personal computer), and the result is downloaded as a control command to a programmable display. By transmitting the control command from the programmable display to the PID unit, the PID unit reads the data requested by the control command from the memory and transmits the data to the programmable display. The programmable display determines whether or not the data is a desired value (normal value) according to the control command. If the data is not normal, the programmable indicator displays parameter values from the personal computer until the normal value is obtained. Repeat operations after input. Through such tuning work, numerical values of P value (proportional band), I value (number of integrations), and D value (differential time) for performing the target control are determined.
[0006]
However, since the above-described tuning operation using the parameter setting editor described above requires a personal computer to be connected to a programmable display, the state where the programmable display is installed at a production site, for example, control In a state where it is incorporated in a panel or the like, it may be difficult to connect the personal computer to the programmable display. In such a case, there is a possibility that the tuning operation cannot be performed.
[0007]
On the other hand, the programmable display disclosed in Patent Literature 1 below includes a communication function (including protocol conversion) with the temperature controller and a function of performing arithmetic processing based on a value input from the touch panel. As a result, the above inconvenience can be solved.
[0008]
[Patent Document 1]
JP 2001-34332 A (publication date: February 9, 2001)
[0009]
[Problems to be solved by the invention]
However, the above-described tuning operation is also required by the programmable display disclosed in the above-mentioned Patent Document 1, so that the parameter input operation via the touch panel on the display screen of the programmable display is not performed. It must be repeated many times until completion. Therefore, it takes a lot of time for the tuning work, and it is very difficult and skillful to set a control command to bring it close to the ideal control state.
[0010]
The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to easily set a setting necessary for PID control in a short time.
[0011]
[Means for Solving the Problems]
In order to solve the above-described problem, the PID control device of the present invention performs the PID calculation based on the deviation between the control amount detected by the detection device and the set target setting value. A PID control device comprising PID calculation means for generating a control signal for giving an output to an output device an operation amount for operating the control amount so as to coincide with a set value, wherein the control amount detected by the detection device is An analog input means for inputting an analog signal representing, an analog output means for outputting an analog signal representing the operation amount given to the output device, a display means having a display surface, and a designated position on the display surface are detected. In order to display a change in the control amount as a curve on the display surface based on the control position input via the indicated position detection means and the analog input means When drawing data is generated and the indicated position on the curve displayed on the display surface is moved, the moving amount of the indicated position calculated from the indicated position detected by the indicated position detecting means is associated with the movement. Drawing data generation means for updating the drawing data so that the shape of the curve changes, and an operation amount generation means for generating the operation amount based on a change in the drawing data. When the PID calculation is not performed, a certain output is secured based on the tieback value set as a default. It is characterized by that.
[0012]
In the above configuration, when the control amount detected by the detection device is input via the analog input unit, the drawing data generation unit generates drawing data representing the change based on the control amount. This drawing data is displayed as a curve on the display surface of the display means. Here, when the drawing data is generated by digital processing, the analog signal must be converted to digital, so the analog input means may have an analog / digital conversion function. The above curve means a broad curve including a straight line as a special curve form.
[0013]
For example, when an operator gives an instruction by touching a curve displayed on the display surface with a finger, the indicated position is detected by an indicated position detecting means such as a touch panel. When the movement amount of the designated position is calculated from the detected designated position, the drawing data generation means updates the drawing data so that the shape of the curve changes based on the movement amount. At this time, for example, the drawing data is updated so that the change at the indicated position of the curve becomes the largest. Thereby, for example, as indicated by a broken line in FIG. 5, a specific portion of the curve changes with the designated position as the apex.
[0014]
Then, an operation amount is generated by the operation amount generation means based on the change between the original drawing data and the updated drawing data. As for this operation amount, the operation amount of the analog signal is given to the output device as a control signal from the analog output means. As a result, the output device changes its output value according to the operation amount.
[0015]
In this way, the control amount is displayed as a curve, and an operation amount for changing the control amount is generated by changing the shape of the curve at the indicated position, so it is possible to visually determine how much the control amount should be changed. I can grasp it. Therefore, setting for PID control can be performed with a simple and simple operation.
[0016]
The PID control device includes parameter generation means for generating a parameter used for performing a PID calculation based on the movement amount of the indicated position and the shape of the curve, and a parameter display for displaying the parameter on the display surface. Means. According to this configuration, if the shape of the curve (for example, overshoot) is known, what kind of parameter can be estimated, and the parameter value is determined based on the movement amount of the designated position. Thus, the parameter generation means obtains the parameter in this way, and displays the parameter on the parameter display means, so that it is possible to confirm what value of the parameter will be when the indicated position changes.
[0017]
It is preferable that the PID control device includes a parameter input unit that inputs parameters used for performing a PID calculation, and the drawing data generation unit updates the drawing data based on the parameters. In such a configuration, since the drawing data is updated by the drawing data generation unit based on the parameter input by the parameter input unit, the operation amount determined by displacing the curve by moving the designated position Can be adjusted.
[0018]
It is preferable that any upper-level PID control device is configured by incorporating the above-described units in a programmable display. In such a configuration, since the programmable display device has the function of the PID control device, it is not necessary to perform PID control by connecting a dedicated PID control device to the programmable display device.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
One embodiment of the present invention will be described with reference to FIGS. 1 to 5 as follows.
[0020]
As shown in FIG. 2, the PID control system according to the present embodiment includes a detection device 1, an output device 2, and a programmable display 3.
[0021]
The detection device 1 is a sensor or a detection device for detecting various control amounts as electrical signals. This detection device 1 uses a sensor or a detection device according to the control amount, for example, in the case of temperature control, a thermocouple, a resistance temperature detector, a thermistor, an encoder, etc. In the case of pressure detection, it is a pressure sensor.
[0022]
The output device 2 outputs, as an electrical signal, an operation amount for manipulating the control amount generated by the programmable display 3 described later so that the control amount detected by the detection device 1 matches the set value. Device. For example, in the case of temperature control, the output device 2 is a heater that adjusts the internal temperature of a furnace or the like to a temperature set based on the temperature detected by the temperature sensor as described above. This is a valve that adjusts the flow rate so that the flow rate is set based on the flow rate detected by the flow rate sensor. Further, in the case of compressor pressure control, the output device 2 operates a motor that drives the compressor so that the discharge pressure of the compressor becomes a pressure set based on the pressure detected by the pressure sensor. Or an inverter.
[0023]
The programmable display 3 as a PID control device includes a CPU 31, a memory unit 32, a VRAM 33, a display 34, a graphic controller 35, a touch panel 36, a touch panel controller 37, an analog input unit 38, and an analog output unit 39.
[0024]
The memory unit 32 includes memories such as a DRAM 32a and a FEPROM (Flash Erasable and Programmable ROM) 32b. The DRAM 32a is mainly used for work during arithmetic processing such as display control, and is also used for temporary storage of data generated in accordance with arithmetic processing by the PID arithmetic processing unit 12 described later. The FEPROM 32b is a rewritable read-only flash memory, and serves as a hard disk drive in a general personal computer. A flash memory does not have a movable part and is resistant to impacts, and thus operates stably even in a poor ambient environment.
[0025]
Further, as shown in FIG. 3, the FEPROM 32b has areas for storing a display control system program, a user screen, a PID calculation processing program, and graph processing data.
[0026]
The display control system program corresponds to the display control unit 11 described later, and is a program for realizing a basic function for performing image display control.
[0027]
The PID calculation processing program corresponds to the PID calculation processing unit 12 described later, generates data for displaying the current control amount input from the analog input unit 38 as a graph (curve) on the display 34, and is displayed on the touch panel 37. When the graph is touched and dragged by the operator, the calculation processing for updating the graph drawing data and the operation amount are calculated based on the movement amount when the graph is moved around the touch position. Calculation processing and calculation processing for generating each parameter used for PID control. The PID calculation processing program performs calculation processing for updating the drawing data of the graph and calculation processing for calculating the operation amount based on the input numerical value.
[0028]
The graph processing data includes a movement amount used for calculation processing for updating the graph drawing data from the movement amount by the PID calculation program and data relating to a graph change pattern.
[0029]
The user screen is created by a drawing editor installed in the personal computer and downloaded to the FEPROM 32b. This user screen includes a base screen to be displayed on the display 34, tag data (to be described later), a processing recognition word W (to be described later) attached to each tag (see FIG. 3A), and the like. It is composed. The above tag is a desired moving image function set at a desired position (area) in order to express a dynamic change such as a numerical value or a straight line at an arbitrary position on the screen.
[0030]
The tag includes a processing recognition word W as shown in FIG. The processing recognition word W is basically created for each event to be executed on the base screen, and includes identification information T, processing information G, and coordinate information C as a set.
[0031]
The identification information T is information for identifying the type of tag described above. The processing information G is information for specifying a procedure for changing an image, and includes a type code G0, conversion information G1, G2, and digit processing information G3 as shown in FIG. 4B. .
[0032]
The type code G0 is a code that defines a data processing form, and represents a type that specifies a combination of the form of input data from the touch panel 36 and the display form of the display 34. The form of the input data is percentage data (%) or actual data (minutes, milliseconds, etc.), and the display form is numerical display (percent data or actual data) or graphic drawing. The type code G0 is set as necessary.
[0033]
The conversion information G1, G2 represents a range width and a range minimum value for converting the input data into values according to the display form (percent data, actual data, etc.), respectively. The conversion is performed by calculation based on a predetermined conversion formula. The digit processing information G3 is set only when actual data is displayed, and is used for controlling the number of significant digits to be displayed and other display formats.
[0034]
When displaying or inputting a numerical value at the designated coordinates, the coordinate information C is constituted by an X-axis coordinate X0, a Y-axis coordinate Y0, a display digit number n, and a unit code d as shown in FIG. . The coordinates (X0, Y0) are coordinates for defining a numerical display position or input position. The display digit number n is information for limiting the number of digits of the displayed numerical value. The unit code d is information relating to a numerical unit. This unit code d is not set if it is not necessary.
[0035]
In addition, when drawing a curve, the coordinate information C is constituted by a plurality of coordinates (X1, Y1),..., Coordinates (Xn, Yn) forming a curve, as shown in FIG.
[0036]
The CPU 31 executes the display control system program and the PID arithmetic processing program stored in the FEPROM 32b, thereby realizing the display / control operation of the programmable display 3 and the PID arithmetic processing.
[0037]
The VRAM 33 is a memory that temporarily holds an image of the user screen displayed on the display 34, and stores the image of the user screen from the FEPROM 32b as dot data in the order displayed in the horizontal direction.
[0038]
The display 34 as a display means is configured by a flat display element such as a liquid crystal panel or an EL panel, and has a display surface (display area) for displaying a screen such as a parameter setting screen 6 described later. Yes. The graphic controller 35 is driver software that draws an image of the screen developed in the VRAM 33 on the display 34.
[0039]
The touch panel 36 as an instruction position detection unit is provided for detecting a touch position (instruction position) on the display surface of the display 34, and an analog resistance film type touch panel or the like is preferable. The touch panel controller 37 converts the output voltage of the touch panel 36 into position detection information (coordinate information) and outputs it.
[0040]
The analog input unit 38 as an analog input means is a part of an interface that takes in the detection signal (analog value) from the detection device 1 and transmits it to the CPU 31. The analog input unit 38 includes an input circuit that receives input analog signals (voltage input and current input), a low-pass filter that removes noise components included in the input signal, an amplifier that amplifies the analog signal that has passed through the low-pass filter, and an amplifier. An A / D converter that converts the analog signal thus passed into a digital signal is included.
[0041]
The analog output unit 39 as analog output means is a part of an interface that outputs an output signal (analog value) to the output device 2 described above. The analog output unit 39 includes a D / A converter that converts a digital signal to be output into an analog signal, an amplifier that amplifies the analog signal that has passed through the D / A converter, and an analog signal (voltage input and current that has passed through the amplifier). And an output circuit for outputting (input).
[0042]
The programmable display 3 reads necessary information out of the state information indicated by the bit device or the word device into the memory unit 32 in a timely manner, while repeatedly reading the processing recognition word W and identifying code T of each processing recognition word W. The content of the input tag specified by is changed by the user's input from the touch panel 36 on which the user screen is displayed. Moreover, the programmable display 3 changes an output tag by this, and draws a figure in the predetermined position on a user screen, or displays a numerical value.
[0043]
Then, the screen for the parameter setting of PID control in the programmable display 3 is demonstrated.
[0044]
As shown in FIG. 5, the parameter setting screen 6 includes a parameter setting unit 61, a bar graph unit 62, a graph window 63, an operation button unit 64, and a monitor unit 65.
[0045]
The parameter setting unit 61 includes setting display units 61a to 61h. Each of the setting display units 61a to 61h displays parameters (numerical values) necessary for PID control, and includes an increase / decrease button for increasing / decreasing the parameters. Since the input of the parameters here is performed by the operator pressing the position of the increase / decrease button on the touch panel 36, the touch panel 36 functions as a parameter input means. Further, a numerical value input device such as a keyboard or a numeric keypad may be used as the parameter input means so that the parameters can be directly input to the setting display units 61a to 61h.
[0046]
The setting display unit 61a displays a numerical value representing the setting value as a percentage of the current value. The setting display unit 61b displays a tieback value. For example, in temperature control, when performing PID calculation, even in a system that operates at an output of 12 to 18% of the rated output, or when PID calculation is not performed, a minimum output of 10% must be secured. If the furnace is not kept heated, the plastic in the furnace will solidify. For this reason, in the specification in which the output value is “0” when the PID calculation is not performed, the tieback value is set as a default for securing a constant output when there is the above-described inconvenience on the system.
[0047]
The setting display unit 61c displays a proportional band (P value) for specifying a range in which proportional operation is performed. The setting display unit 61d displays the number of integrations (I value), and the setting display unit 61e displays the differential time (D value).
[0048]
The setting display unit 61f displays a range where PID calculation is not performed. In this range, if the current value approaches the target value, no calculation is performed even if there is a difference deviation.
[0049]
The setting display unit 61g displays a bias value for bringing the current value close to the ideal value. The setting display unit 61h displays a data sampling time when filtering. This sampling time is a time required for sampling when filtering is performed by taking an average value of the current values sampled a plurality of times in order to remove noise superimposed on the input current value.
[0050]
The bar graph unit 62 includes bar graphs 62a to 62c. The bar graph 62a indicates the target value, the bar graph 62b indicates the output value, and the bar graph 62c indicates the output value. The bar graphs 62a to 62c indicate the respective values with a triangular instruction section.
[0051]
The graph window 63 displays a graph representing the control amount. The graph displayed in the graph window 63 is drawn based on the coordinate information C (see FIG. 4D).
[0052]
The operation button unit 64 includes operation buttons 64a to 64c. The operation buttons 64a to 64c are mainly used to determine a value, and are operated, for example, when fixing the vertex of the graph or determining the display value of each setting display unit 61a to 61h. Therefore, the number of buttons provided in the operation button unit 64 is arbitrary, and is provided in association with a value to be determined.
[0053]
The monitor unit 65 includes a current value display unit 65a that displays a current value and a set value display unit 65b that displays a set value. The monitor display is performed by displaying the current value and the set value. For example, in the case of temperature control, the current temperature is displayed as the current value, and the set temperature is displayed as the set value. The current value display unit 65a and the set value display unit 65b are provided at different positions specified by the coordinates of the above-described coordinate information C (see FIG. 4C). The numerical values displayed on the current value display unit 65a and the set value display unit 65b are displayed by processing according to the processing information G described above (see FIG. 4B).
[0054]
Furthermore, the principal part which performs PID control in the programmable display 3 is demonstrated.
[0055]
As shown in FIG. 1, in the programmable display 3, a display control unit 11 and a PID calculation processing unit 12 are provided. The display control unit 11 and the PID calculation processing unit 12 are functional blocks realized by the CPU 31 executing the above-described display processing system program and PID calculation processing program, respectively.
[0056]
Data of the current control amount (current value) from the detection device 1 digitized by the analog input unit 39 is input to the PID calculation processing unit 12 as PID calculation means via the PID calculation processing unit 13. The drawing calculation unit 12a as the drawing data generation means of the PID calculation processing unit 12 displays the current value data in the graph window 63 so that the current value data is displayed as the graph C1 in the graph window 63 shown in FIG. An operation for converting to coordinate data (drawing data) is performed.
[0057]
Further, when the operator's finger touches the touch panel 36 and moves in the Y direction (arrow direction in the figure), the drawing calculation unit 12a displays data on the movement distance and direction (coordinate increase / decrease) according to the movement. 36, the displacement of the touch position (instructed position) where the operator's finger touches the touch panel 36 becomes the largest based on the increase / decrease data, and the displacement becomes smaller as the distance from the position is increased. An operation for changing the drawing data is performed. For this calculation, data related to the graph change pattern of the graph processing data stored in the FEPROM 32b is used. In addition, when each parameter displayed on the setting display units 61a to 61h is updated by an operator's input, the drawing calculation unit 12a calculates drawing data to be changed based on the parameter.
[0058]
In addition, the drawing operation unit 12a creates drawing data based on the parameters input to the setting display units 61a to 61h or the parameters generated by the analysis unit 12c. Specifically, the drawing calculation unit 12a performs a PID calculation based on the parameters to determine the shape of the changed part of the graph, and calculates the drawing data of the changed part of the graph according to the change amount of the touch position. .
[0059]
Furthermore, the drawing calculation unit 12a generates data for displaying the instruction units of the bar graphs 62a to 62c of the bar graph unit 62 so as to be displayed at positions corresponding to the respective values.
[0060]
An operation amount calculation unit 12b as an operation amount generation unit of the PID calculation processing unit 12 compares the drawing data of the current value with the above-described changed drawing data, and gives the output device 2 based on the difference between the two. Calculate the operation amount. Further, the operation amount calculation unit 12b calculates the operation amount by performing PID calculation based on the parameters displayed on the setting display units 61a to 61h described above or the parameters generated by the analysis unit 12c.
[0061]
The analysis unit 12c as a parameter generation unit of the PID calculation processing unit 12 analyzes the drawing data changed by the drawing calculation unit 12a, and generates parameters to be displayed on the back setting display units 61a to 61h. Specifically, the analysis unit 12c specifies the shape of the graph of the part where the touch position has changed, specifies the type of each parameter from the shape, and calculates the value of the parameter specified from the amount of change in the touch position. To do. The shape of the graph is specified based on, for example, the closest graph pattern by comparing the coordinate data of the graph with the coordinate data of various graph patterns (overshoot, undershoot, DC portion, etc.) stored in the FEPROM 32b. However, the specific method is not limited to this.
[0062]
The analysis unit 12c may compare the current drawing data with the changed drawing data, identify a change pattern based on the difference between the two, and estimate each parameter from the change pattern. .
[0063]
The display control unit 11 draws a graph in the graph window 63 based on the drawing data calculated by the drawing calculation unit 12a. Further, the display control unit 11 displays the parameters generated by the analysis unit 12c on the setting display units 61a to 61h. Further, the display control unit 11 as a parameter display unit displays the set value set in the setting display unit 61 a on the set value display unit 65 a of the monitor unit 65 on the parameter setting screen 6 and is input from the analog input unit 38. The current value is displayed on the current value display unit 65b of the monitor unit 65.
[0064]
Next, the operation of the PID control system configured as described above will be described. Here, a case where temperature control in the furnace is performed will be described.
[0065]
First, a detection signal indicating a current value output from a thermocouple as the detection device 1 is input from the analog input unit 38 and converted into a digital signal here. Upon obtaining the digital current value, the drawing calculation unit 12 a displays the current value on the bar graph 62 c and the graph window 63.
[0066]
Here, when the operator touches a position of the graph on the graph window 63 on the touch panel 36 and moves (drags) the touched position (instructed position) upward or downward, the drawing calculation unit 12 a The data of the movement amount and direction (coordinate increase / decrease) is calculated and acquired from the coordinate data of the movement start point and end point output from the touch panel 36. Then, the drawing calculation unit 12a calculates drawing data to be changed based on the moved increase / decrease data. At this time, data relating to the graph change pattern of the graph processing data is used. In this data, the increase / decrease amount according to the distance from the designated position and the positions of both ends starting to change are determined in advance according to the movement amount. Therefore, for example, as shown in FIG. 5, when the designated position P0 in the graph C1 is dragged upward to the designated position P1, drawing data as indicated by a broken line is newly calculated, and the graph window 63 displays the graph C2. Is displayed.
[0067]
When the desired graph cannot be changed by one drag, a desired graph is formed by dragging different designated positions. At this time, for example, when the operation button 64a of the operation button unit 64 is turned ON, the vertex position of the graph once changed (indicated position P2 in the case of the graph C2) is fixed by the drawing operation unit 12a. Thereby, the graph shape of another location can be adjusted, without destroying the already adjusted graph shape. In addition, since new drawing data is created by the drawing calculation unit 12a based on the parameters changed in the setting display units 61a to 61h, it is difficult to drag the indicated position by slightly changing the desired parameters. Fine adjustment of the graph shape can be performed. Therefore, the operation amount can be determined with high accuracy.
[0068]
In a dedicated PID control device such as a temperature controller, there are models that can perform parameter setting by auto-tuning. However, although auto-tuning can prevent the operator from performing the tuning work, it cannot fully reflect the operator's intention to adjust, and is an unsatisfactory function in terms of performing desired control.
[0069]
On the other hand, as described above, the method of finely adjusting the graph shape creates a rough graph shape and fine-tunes the graph shape by inputting parameters, thereby determining the operation amount almost as desired by the operator. can do.
[0070]
On the other hand, the analysis unit 12c specifies the shape of the graph of the portion where the touch position has changed, specifies the type of each parameter from the shape, and calculates the value of the parameter specified from the amount of change in the touch position. The parameters thus obtained are displayed on the setting display sections 61a to 61h by the display control section 11.
[0071]
For example, the P value (differential time) and the tieback value increase when the curve changes from a gentle curve to a sharply changing curve, and decrease when the opposite curve changes. Specifically, as shown in FIG. 6, the coordinates of the point O1 touched by the operator on the graph A representing the output result so far indicated by a solid line is (X1, Y1), and the operator If the coordinates of the point O2 where the dragging of (X2) is completed are (X2, Y2), a new graph B including the point O2 is drawn. For such a new graph B, if it is specified that the change pattern of the Y-axis coordinate, that is, the change from the graph A to the graph B accompanying the change from Y1 to Y2, is a change in the overshoot part, Increase the parameter of the P value on which the change in overshoot depends. In addition, the drawing calculation unit 12a may generate drawing data of the graph B using the parameters.
[0072]
As the new graph is drawn, the operation amount calculation unit 12b compares the current drawing data and the changed drawing data with respect to the same X coordinate value, and converts the difference between them into an operation amount. This operation amount is given to the analog output unit 39 as an increase / decrease amount of the output value of the output device 2. When the analog output unit 39 converts the operation amount (heater current) into a digital signal and gives the output device 2, the heater as the output device 39 increases the heater current according to the operation amount to increase the temperature (output value). ). At this time, the detection device 1 detects a new current temperature when the output value of the output device 39 changes. As described above, the current temperature is taken into the programmable display 3 from the analog input unit 38 and is reflected in the graph display and the monitor display on the monitor unit 65. Moreover, since the set temperature as the set value is also displayed on the monitor unit 65, the current temperature with respect to the set temperature can be compared.
[0073]
It should be noted that the current value may be changed by dragging the indicating part of the bar graph 62c. In this case, the analysis unit 12c compares the current value before the change with the current value after the change, and specifies each parameter in the same manner as the above-described process for specifying the parameter from the drawing data.
[0074]
As described above, the PID control system according to the present embodiment determines the operation amount to be given to the output device 2 and the parameters at that time by dragging the graph displayed on the display 34. The operation amount can be determined visually. This eliminates the need for adjusting the operation amount by changing the parameter many times in order to determine the optimum parameter, as in the prior art, and greatly reduces the time and effort required for tuning. Further, since the current value is displayed as a graph, the result of giving the operation amount to the output device 2 can be easily confirmed.
[0075]
In addition, since the programmable display 3 includes the analog input unit 38 and the analog output unit 39, an analog control amount from the detection device 1 is directly input to the programmable display 3 and an analog operation amount is input to the programmable display 3. To the output device 2 directly. Thus, if a monitoring function such as the monitor unit 65 is added, a PID control device such as a temperature controller can be configured with the programmable display 3 alone, and a dedicated PID control device is not required. As a result, the system configuration can be simplified. Moreover, different types (temperature, flow rate, pressure, etc.) can be obtained by individually preparing PID calculation processing programs for controlling a plurality of types of control amounts, or by making the PID calculation processing program itself versatile. A general-purpose PID control device for controlling the control amount can be provided.
[0076]
In the present embodiment, the example in which the user touches the touch panel 36 of the programmable display 3 and drags the graph has been described, but the method of dragging the graph is not limited to this. For example, in a display device or a personal computer that does not include the touch panel 36, the graph can be dragged in the same manner by using a point device such as a mouse.
[0077]
Various arithmetic processes in the PID arithmetic processing unit 12 are not limited to the above-described technique, and other techniques may be used as long as the same result can be obtained.
[0078]
Further, the display of the parameter setting screen 6 shown in FIG. 5 is not limited to the above-described method using tags, and other methods may be used. For example, in a personal computer or the like, an application program capable of dragging a graph and inputting parameters as in the parameter setting screen 6 is installed.
[0079]
By the way, the programmable display device 3 can tank the current value by providing the memory unit 32 with an SRAM or a reader / writer capable of reading and writing data to and from the memory card. By using the tanked data, it is possible to create a trend graph or a form such as a daily report.
[0080]
Moreover, the programmable display 3 can have an original function as a programmable display instead of a PID control device by providing a serial communication interface. Thereby, when not using as a PID control apparatus, the programmable display 3 is connected with PLC and a device is controlled or an operation state is displayed.
[0081]
【The invention's effect】
As described above, the PID control apparatus of the present invention performs the PID calculation based on the deviation between the control amount detected by the detection device and the set target set value, so that the control amount matches the set value. PID calculation means for generating a control signal for giving an operation amount for operating the control amount to the output device, analog input means for inputting an analog signal representing the control amount detected by the detection device, and An analog output means for outputting an analog signal representing the operation amount given to the output device, a display means having a display surface, an indicated position detection means for detecting an indicated position on the display surface, and the analog input means And generating drawing data for displaying a change in the control amount as a curve on the display surface based on the control amount input in When the indicated position on the displayed curve is moved, the shape of the curve is changed so that the shape of the curve is changed based on the movement amount of the indicated position calculated from the indicated position detected by the indicated position detecting means along with the movement. Drawing data generating means for updating drawing data; and an operation amount generating means for generating the operation amount based on a change in the drawing data. When the PID calculation is not performed, a certain output is secured based on the tieback value set as a default. It is a configuration.
[0082]
Thereby, the control amount is displayed as a curve, and the operation amount is generated by displacing the curve at the designated position, so it is possible to visually grasp how much the control amount should be changed. Therefore, setting for PID control can be performed with a simple and simple operation. Therefore, it is possible to greatly reduce the labor required for the tuning operation for adjusting the operation amount, and to perform the PID control efficiently.
[0083]
The PID control device includes parameter generation means for generating a parameter used for performing a PID calculation based on the movement amount of the indicated position and the shape of the curve, and a parameter display for displaying the parameter on the display surface. Therefore, it is possible to grasp what parameters are used when a desired operation amount is determined based on a change in the designated position. Therefore, by recording the parameters, the same operation amount can be reproduced.
[0084]
The PID control device includes parameter input means for inputting parameters used for performing PID calculation, and the drawing data generation means updates the drawing data based on the parameters. The operation amount determined by displacing the curve can be finely adjusted by the parameter. Therefore, there is an effect that more accurate PID control can be performed.
[0085]
Since any of the higher-level PID control devices is configured by incorporating the above-mentioned means into a programmable display, the programmable display has the function of the PID control device, and a dedicated PID control device is provided for the programmable display. There is no need to connect and perform PID control. Therefore, there is an effect that the configuration of the control system can be simplified.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a main part of a PID control system according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a schematic configuration of the PID control system.
FIG. 3 is a diagram showing a program and data stored in FEPROM of a programmable display in the PID control system.
FIGS. 4A to 4D are explanatory diagrams showing a configuration of processing recognition words included in a user screen displayed on the programmable display or the like, and an explanatory diagram showing a configuration of processing information in the processing recognition words, respectively. FIG. 4 is an explanatory diagram showing a configuration of processing information in the processing recognition word, and an explanatory diagram showing a configuration of two types of coordinate information in the processing recognition word.
FIG. 5 is a front view showing the programmable display displaying a parameter setting screen for setting parameters used for PID control.
FIG. 6 is a diagram illustrating a mechanism for converting a graph set on the parameter setting screen into a parameter when the graph is changed by a drag operation;
[Explanation of symbols]
1 Detection device
2 Output device
3 Programmable display (PID controller)
6 Parameter setting screen
11 Display control means (parameter display means)
12 PID calculation processing unit (PID calculation means)
12a Drawing operation part (drawing data generation means)
12b Operation amount generation means (operation amount calculation unit)
12c Analysis unit (parameter generation means)
34 Display (display means)
36 Touch panel (indicated position detection means, parameter input means)
38 Analog input section (analog input means)
39 Analog output (analog output means)
65 Graph window
C1, C2 graph (curve)

Claims (5)

An operation amount for operating the control amount so that the control amount matches the set value by performing PID calculation based on a deviation between the control amount detected by the detection device and the set target set value. A PID control device comprising a PID calculation means for generating a control signal for supplying to the output device,
Analog input means for inputting an analog signal representing a control amount detected by the detection device;
Analog output means for outputting an analog signal representing the operation amount to be given to the output device;
Display means having a display surface;
Indicated position detecting means for detecting the indicated position on the display surface;
Based on the control amount input through the analog input means, the drawing data for displaying the change in the control amount as a curve on the display surface is generated and the instruction on the curve displayed on the display surface Drawing data generation for updating the drawing data so that when the position is moved, the shape of the curve changes based on the amount of movement of the designated position calculated from the designated position detected by the designated position detecting means. Means,
An operation amount generating means for generating the operation amount based on a change amount of the drawing data ,
When the PID calculation is not performed, a constant output is ensured based on a tieback value set as a default . Parameter generating means for generating parameters used for performing PID calculation based on the amount of movement of the indicated position and the shape of the curve;
The PID control apparatus according to claim 1, further comprising parameter display means for displaying the parameter on the display surface. A parameter input means for inputting parameters used for performing the PID calculation;
The PID control apparatus according to claim 1, wherein the drawing data generation unit updates the drawing data based on the parameter.   4. The PID control apparatus according to claim 1, wherein each of the means is incorporated in a programmable display.   The PID control apparatus according to claim 1, wherein the drawing data generation unit fixes the vertex position of the curve that has changed once.

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