JP3575913B2 - Programmable controller - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a programmable controller that controls a plurality of devices in a predetermined order.
[0002]
[Prior art]
Conventionally, for example, in order to execute the control as shown in the flow sheet of FIG. 7, first, a flow sheet is created, and then a flowchart is created with reference to the created flow sheet, and then, as shown in FIG. Creating a ladder diagram.
[0003]
In recent years, a program called a programming console or a tool called a graphic programming console has been developed for creating a program. The programming console displays one line each time the program is input, and the graphic programming console displays a CRT. Alternatively, the entire ladder diagram is displayed on a large liquid crystal panel.
[0004]
The flow sheet indicates the control conditions and the state of the device to be controlled using arrows (indicating the operation direction) and pictures (for example, pumps), and thereby allows the control target to be accurately and easily controlled. The operation of the device can be described.
[0005]
The flow sheet of FIG. 7 describes the operation of the device for pumping water 4 from the lower tank 2 to the upper tank 3 by the pump 1, and the control conditions are as follows.
[0006]
(1) The pump 1 operates when the water level of the upper tank 3 is lower than "L" (33W2L), and stops when the water level is higher than "H" (33W2H).
[0007]
(2) When the water level in the lower tank 2 is equal to or lower than "LL" (33W1LL) or abnormal (30X), the pump 1 is stopped emergency.
[0008]
The motor 5 for driving the pump 1 is controlled by turning on / off the contactor (88) 6, and is controlled so that the contactor (88) 6 is opened when an abnormality such as an overcurrent or a ground fault occurs.
[0009]
[Problems to be solved by the invention]
By the way, in the above-mentioned conventional programmable controller, the program creation stage is complicated, and the ladder diagram created by the program creator as shown in FIGS. 8A and 8B is also different ( There are many different combinations to achieve the same behavior, and there can be multiple programs). For this reason, there have been problems that a long working time is required and maintenance such as debugging of a program is hindered.
[0010]
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a programmable controller that can create a program having common contents in a short time and without depending on the experience of an operator.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is a storage means for storing a pattern of various parts constituting a flow sheet describing operation of a plant and control conditions corresponding to the pattern as a pair for each part; A flow sheet creating means for selecting and arranging the pictures of the respective parts stored in the storage means based on an instruction from the user and connecting them to create a flow sheet; A control program creating means for connecting control conditions corresponding to the picture of each part to create a command word for operating the controlled device, and a flow sheet by the flow sheet creating means Display means for displaying the creation status.
[0012]
According to this configuration, a control program that describes the operation of the control target device can be obtained only by creating a flow sheet by arranging individual patterns as in the case of drawing by CAD. Therefore, it is possible to create a program with common contents in a short time and without depending on the difference in the experience of the operator.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
<Configuration of programmable controller>
FIG. 1 is a block diagram showing a configuration of an embodiment of a programmable controller according to the present invention.
[0015]
In the programmable controller 20 of this embodiment, by performing an operation of creating a flow sheet by the programming tool 21, the arithmetic processing unit 23 can simultaneously create a command word based on the flow sheet. In the storage unit 24 constituted by a hard disk device or the like, for example, a pattern of each part and a rule corresponding to the pattern as shown in FIG. By arranging and connecting individual pictures, a control program (comprising a plurality of command words) for operating the controlled device behind the drawing is automatically created. The automatically created control program is written in the data area of the storage unit 24. The operation of the programming tool 21 is performed while viewing the screen of the CRT 22 as in the case of drawing by ordinary CAD.
[0016]
The program controller 20 includes, in addition to the programming tool 21, the arithmetic processing unit 23, and the storage unit 24, an input unit 25 for inputting various kinds of information for operating the controlled device, and a control unit 26 for controlling each unit of the apparatus. And an output unit 27 that outputs a control signal to a device to be controlled. In this case, the control unit 26 includes a ROM 28 in which a program for controlling the control unit 26 is written, and a RAM 29 used in the operation of the control unit 26. Further, the arithmetic processing unit 23 outputs a control signal according to a control program to the output unit 27 using input data and output data stored in the storage unit 24 according to a timing signal from the control unit 26. The information supplied to the input unit 25 includes, for example, a signal output when the water level of the upper tank 3 becomes “L” or less and the water level of the lower tank 2 becomes “LL” in the control shown in the flow sheet of FIG. "A signal output when the value becomes equal to or less than".
[0017]
As described above, the storage unit 24 stores a program element equivalent to each element of the flow sheet shown in FIG. 7 as a pair of a pattern and a rule corresponding to the pattern, for each part. In this case, each pattern and its rules are as follows.
(A) When the water level is equal to or lower than "LL", the controlled device (pump 4) stops.
A dotted arrow (...>) indicates a stop.
(B) Control target equipment operation from water level “L” or lower to “H”.
The solid arrow (->) indicates operation.
(C) The device to be controlled is shown.
A →, → B indicate the flow of the controlled object.
C ...> * indicates that the device to be controlled is stopped under the condition of C. (d) Protection is detected for the device D to be controlled.
By arranging and connecting the patterns of these parts, the flow sheet shown in FIG. 3 is created, and the rules are connected behind the flow sheet to automatically complete the control program. In this case, the operation for arranging and connecting the pictures of the parts is performed by the programming tool 21 as described above.
[0019]
The operation of the pump 1 based on the created flow sheet is as follows.
If the condition of the failure is not satisfied in step a, the condition of "LL" or less is not satisfied in step b, and the condition of "L" or less is satisfied in step c, the pump 1 It is in operation. On the other hand, when the conditions of steps a and b are not satisfied and the condition of step c is satisfied, the pump 1 is stopped.
[0020]
The storage unit 24 corresponds to a storage unit, and the programming tool 21 corresponds to a flow sheet creation unit. The CRT 22 corresponds to a display unit, and the arithmetic processing unit 23 corresponds to a control program creating unit.
[0021]
<Operation of programmable controller 20>
<< Operation of programming tool 21 >>
FIG. 4 is a flowchart showing the operation of the programming tool 21.
[0022]
First, when there is an operation for starting the creation of a flow sheet (YES in step S10), a screen for creating a flow sheet is displayed on the CRT 22 of the programming tool 21 (step S12). Next, it is determined whether or not there is an operation for connecting parts (step S14). In this case, since the operation of selecting the component has not been performed at the time when the operation of the programming tool 21 is started, it is determined in the next step S16 whether or not the operation of selecting the component has been performed. In this determination, when it is determined that there is an operation for selecting a part, the process proceeds to step S18, where the selected part is read from the storage unit 24 and its pattern is displayed. On the other hand, if it is determined that there is no operation for selecting a component, the process returns to step S14.
[0023]
When there is an operation of selecting a part and the corresponding part is read from the storage unit 24 and its pattern is displayed, it is next determined whether or not there is an operation to end the control program creation process ( Step S20). In this determination, when it is determined that there is an operation for ending the control program creation processing, an end of the control program creation is instructed to the arithmetic processing unit 23 (step S22), and further, in step S24, initialization and an initial screen Is displayed, the process returns to step S10. On the other hand, if it is determined that there is no operation to end the control program creation processing, the process returns to step S14.
[0024]
On the other hand, if it is determined in step S14 that there is an operation to connect components, it is determined whether or not two or more selected components are present (step S26). In this case, the connection cannot be established if there is only one selected component, so the process of step 26 is executed in a sense excluding one case.
[0025]
If it is determined that the number of selected components is two or less, the process returns to step S10, and processing is started from the beginning. On the other hand, if it is determined that the number of selected components is two or more, the process proceeds to step S28, and the connected components are connected. Next, instruction processing is instructed to the arithmetic processing unit 23 (step S30). After performing this process, the process returns to step S10.
[0026]
As described above, when the user performs an operation of selecting a part, the programming tool 21 displays a picture of the part on the CRT 22. When the user performs an operation of connecting the components, the components are connected on the CRT 22.
[0027]
<< Operation of Operation Processing Unit 23 >>
FIG. 5 is a flowchart showing the operation of the arithmetic processing unit 23.
First, it is determined whether there is an instruction to create a command word (step S50). If it is determined in this determination that there is an instruction to create a command word, the process proceeds to step S52, where control conditions are read from the storage unit 24 according to the control program creation instruction (step S52). Then, a command word of the control program is created based on the read control conditions (step S54), and the created command word is stored in the storage unit 24. After performing this process, the process returns to step S50. Thereafter, each time there is an instruction to create a command, a command is created based on the control condition, and the control program is completed.
[0028]
On the other hand, if it is determined in step S50 that there is no instruction to create a command word, then it is determined whether there is an instruction to end creation of the control program (step S58). In this determination, when it is determined that there is an instruction to end the creation of the control program, the registers and the like are initialized (step S60), and the process is terminated. On the other hand, when it is determined that there is no instruction to end the control program creation, the process proceeds to step S60, and it is determined whether or not there is an operation for stopping the process. In this determination, when it is determined that there is an operation to stop the process, the process ends, and when it is determined that there is no operation to stop the process, the process proceeds to step S64. In step S64, it is determined whether or not there is a control output instruction from the control unit 26. In this determination, when it is determined that there is a control output instruction, the process proceeds to step S66, and a control signal according to a control program is supplied to the output unit 27 using the data stored in the storage unit 24. Thereby, the control signal is supplied to the control target device.
[0029]
As described above, in this embodiment, the patterns of the various parts constituting the flow sheet describing the operation of the plant and the control conditions corresponding to the patterns are registered as pairs for each part, and the CRT 22 of the programming tool 21 is registered. By looking at the screen, selecting and arranging the pictures of the registered parts as appropriate, and performing an operation of connecting them, the control conditions corresponding to the pictures are connected to complete the command. If the pictures are arranged and connected until the plant represented by the flow sheet is completed, a control program directly connected to the plant control specifications is completed.
[0030]
Therefore, a control program that describes the operation of the controlled device can be obtained simply by creating a flow sheet by arranging the individual patterns as in the case of drafting by CAD. A program with the contents described above can be created.
[0031]
It should be noted that depending on the control content of the plant, there are cases where it cannot be expressed in the flow sheet. In such a case, it is difficult to similarly express a sequence block obtained by modifying the flow sheet. However, by adding a comment (special specification) process to the flow sheet according to the embodiment of the present invention, it is possible to complete the program in a form conforming to the control specification. For example, when the following additional conditions are added to the plant represented by the flow sheet shown in FIG. 7, the special condition area 41 is provided separately from the flow sheet area 40 as shown in FIG. Special conditions are also processed in the same way as the processing.
[0032]
Additional condition: When controlling the pump, control is performed after manual / automatic mode switching. When automatic, the pump is controlled according to the water level in the upper and lower tanks. When manual, the pump can be controlled regardless of the water level in the upper and lower tanks.
[0033]
By using the sequence block modified from the flow sheet, the software in the controller can be easily designed if the operation specifications of the plant are determined.
[0034]
【The invention's effect】
As described above, according to the programmable controller of the first aspect, the patterns of various parts constituting the flow sheet describing the operation of the plant and the control conditions corresponding to the patterns are registered as pairs for each part. By creating a flow sheet by arranging the patterns of the registered parts, a control program that describes the operation of the controlled device can be obtained. A program with the contents described above can be created.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment of a programmable controller according to the present invention.
FIG. 2 is a diagram showing an example of a pattern used in the programmable controller according to the embodiment and rules corresponding to the pattern.
FIG. 3 is a diagram showing an example of a flow sheet created by the programmable controller of the embodiment.
FIG. 4 is a flowchart showing an operation of the programmable controller of the embodiment.
FIG. 5 is a flowchart showing an operation of the programmable controller of the embodiment.
FIG. 6 is a diagram for explaining another embodiment of the programmable controller of the embodiment.
FIG. 7 is a diagram showing an example of a flow sheet conventionally used.
FIG. 8 is a ladder diagram of the flow sheet of FIG. 7;
[Explanation of symbols]
Reference Signs List 20 Programmable controller 21 Programming tool 22 CRT
23 arithmetic processing unit 24 storage unit 26 control unit

Claims (1)

Storage means for storing, for each part, a pattern of various parts constituting the flow sheet describing the operation of the plant and a control condition corresponding to the pattern,
Flow sheet creation means for creating a flow sheet by selecting and arranging the patterns of the respective parts stored in the storage means based on an instruction from the user and connecting them, and
By connecting the pictures of the parts by the flow sheet creating means, a control program creating means for creating a command for operating the control target device by connecting control conditions corresponding to the pictures of the parts,
A programmable controller comprising:

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