JP6992264B2 - Programmable logic controller memory management method - Google Patents

Description

The present invention relates to a memory management method for a programmable logic controller (hereinafter referred to as PLC).

Currently, the operation of the controller is generally controlled by a dedicated program. As the description language of this program, for example, a language compliant with the IEC (International Electrotechnical Commission) 611131-3 standard (JISB3503) is used.

The programming created by the language conforming to the IEC611131-3 standard is created by using the program creation support device of Patent Document 1 and has the following features.

(1) POU definition and parameter setting In the IEC61131-3 standard, a program created by a user is defined as a type called POU (Program Organization Unit), and these are instantiated by registering them in a task or another POU. In addition to general-purpose programs, POUs with limited functions such as numerical display, numerical calculation, and feedback control are also available. It is required to create these programs efficiently and not to stop PLC as much as possible even after operation. As for PLC, a trade name of sequencer is also generally used.

(2) Online change of POU, variable definition, variable parameter After the operation of PLC is started, online change is performed to replace POU etc. without stopping PLC, so the size and address as an instance and variables inside POU are programmed. It is managed by a programming tool so that it does not change before and after the change. Swapping this state is called an online change.

(3) Online program change in a redundant PLC In many cases, a PLC has a master / slave redundant configuration as a redundant function (backup in the event of a failure, etc.). According to this duplication configuration, the replacement of the program is performed on the master side, and the replaced program is copied to the slave side.

Japanese Patent Application Laid-Open No. 2008-204237

As shown in FIG. 7, the POU is roughly divided into a variable definition part and a logic definition part, and both of them are transferred as an application file. Measured values and the like are copied from field equipment to this variable definition part, and operations are performed while referring to the measured values in the logic definition part.

At this time, the duplicated PLC makes it possible to instantly switch the slave to the master when there is an abnormality in the master by copying the data from the master to the slave. However, the slave has slave-specific information, and that data cannot be copied from the master.

Further, regarding POU such as integration, there are a part where data can be copied from the master to the slave during the calculation of integration and a part where it is not good, and the content is different for each POU.

The present invention has been made to solve such a conventional problem, and an object of the present invention is to safely and surely execute an online change of a POU in a PLC duplicated in a master / slave .

The present invention relates to a method of managing the memory of a programmable logic controller that controls a task configured by a POU (Program Organization Unit). In this method, the POU is divided into groups for each purpose, and the POU is arranged and managed in the memory in the divided group units, and the group is divided in the division management step. It has a group classification step of classifying into a dedicated group when the POU is larger than a certain value.

In one aspect of the present invention, if there is an online change to add or change the POU or variable during the operation of the programmable logic controller, the addition / change / initialization information of the variable definition in the instance area corresponding to the POU is marked. It also has a marking step to give.

In this case, if the information at the time of the online change exceeds a predetermined size in the mark addition step, the mark can be added to the change / equalization map of the variable definition.

Further, if the programmable logic controller is duplicated in the master / slave, the portion not copied from the master to the slave may have an online change equalization filter step defined in the variable definition.

In the mark addition step, if the programmable logic controller acquires the data of the added / changed portion, each mark can be erased.

According to the present invention, online change of POU can be safely and surely executed in the PLC duplicated in the master / slave .

The conceptual diagram of the memory arrangement in the memory management method which concerns on embodiment of this invention. Detailed diagram of the variable definition. (A) is a block diagram of a system that executes the memory management method, and (b) is a block diagram of PLC shown in (a). The programming work flow diagram based on the system of FIG. The figure which shows an example of the program POU which was automatically generated. Individual parameter adjustment screen diagram. Conceptual diagram of the memory arrangement of the conventional example.

Hereinafter, the memory management method according to the embodiment of the present invention will be described. In this memory management method, a POU instance storage area is secured for each task in the PLC storage device, and a POU instance area is placed in the instance storage area to manage the PLC memory.

≪Execution system≫
The configuration of the system 1 that executes the memory management method will be described with reference to FIG. PLC2 in FIG. 3A is mainly used for creating an application for instrumentation in accordance with the JISB3503 standard.

In this PLC2, POUs are prepared for various functions for instrumentation, and processes such as program creation / editing (change) / debugging are executed according to instructions from PADT (Programming And Debugger) 4. The PADT 4 is mounted on a computer 3 connected to the PLC 2 via Ethernet (registered trademark) 7, and an instrument creation support tool 5 is mounted on the computer 3.

Further, as shown in FIG. 3B, the PLC 2 includes a management CPU (Central Processing Unit) 11a that executes various arithmetic controls, a program memory 11b that stores and manages POUs, and an instance storage corresponding to each POU. It is provided with a data memory 11c arranged in an area. In FIG. 3 (b), the instance storage area i ₁ is arranged corresponding to POU (1), the instance storage area i ₂ is arranged corresponding to POU (2), and the instance storage area i 2 corresponds to POU (n). The instance _storage area in is arranged.

_A task-based instance area (hereinafter abbreviated as an instance area) 12 shown in FIG. 2 is placed in each of the instance storage areas i1 to inn, and _a POU variable definition 13 is stored in the instance area 12. Has been done. Specifically, in the case of the general variable definition 11a, the type information 13c, the initial value 13d, the current value 13e, the addition / change / initialization information 13f, and the equalization filter information 13g are stored. Further, in the variable definition 13b having a size larger than a certain size, a change / equalization map 13h is further added. Whether or not the variable definition 13b is applicable may be determined by comparison with a predetermined threshold value.

In the management CPU 11a, two baseboards (not shown) are connected by a cable, and a management CPU module is mounted on each of them. Notifies the standby mode and realizes a PLC duplication system with multiple CPUs. According to this PLC duplication system, each management CPU module has the same memory configuration and operates the same application program. Each management CPU module is shown as CPUs (1) and (2) in FIG. 1, the CPU (1) is mounted on the master side, and the CPU (2) is mounted on the slave side.

≪Work procedure≫
(1) Input support A work procedure (step) using the system 1 will be described. Conventionally, as shown in FIG. 4, a simple operation of arranging a POU (hereinafter referred to as a function POU) having functions such as numerical display and numerical integration based on the instrumentation item table D and setting parameters is performed. It has been devised so that it can be programmed by repeating.

However, since the user (human) programs the parameters while looking at the measurement item table D, many input errors are seen. Therefore, in the system 1, the portion automatically generated by using the instrument creation support tool 5 is increased, and the trouble of inputting by the user is saved.

To explain in detail, the user creates a counting item table D of the program to be created and manually defines the system configuration (S01, S02), as in the conventional S01 and S02. However, it differs from the conventional one in that the instrument creation support tool 5 is used for the definition of the global variable and the definition of the function POU shown in S03 and S04.

That is, data is read from the instrumentation item table D and the instrumentation initial value file F1 by the instrumentation creation support tool 5, and the number of function POUs to be created and the rule of the name are set by the instrumentation creation support tool 5. Here, a global variable to be input to the function POU can be defined as a structure, and a parameter setting dialog can be prepared for each registered function POU component to facilitate input.

Then, the instrument creation support tool 5 outputs the CSV file F2 for global variables of the function POU and the XML file F3 for the program POU in which the function POU is arranged from the instrument item table D and the instrument initial value file F1 to PADT4. do.

Further, PADA4 reads the CSV file F2 and the XML file F3, and automatically programs global variables and function POUs. Here, when setting parameters different from the instrumentation item table D and the instrumentation initial value file F1, set them in PADT4. Note that FIG. 5 shows the screen display G1 of the function POU automatically generated by importing the XML file F3 output from the instrument creation support tool 5, and Table 1 shows the CSV file output from the instrument creation support tool 5. It shows a global variable that is automatically generated by taking in F2.

At this time, if you want to set a parameter different from the instrumentation item table and the instrumentation initial value file F1, set it with a programming tool. Here, as shown by the arrow G1 in FIG. 6, the screen G2 for each instrumentation component is displayed by double-clicking the parameter (variable name) in Table 1 after the automatic generation, and the parameter can be changed. ..

(2) Online change, etc. Compile with PADT4 (S05) and generate the file of application 6. As shown in FIG. 1A, the applications 6 created at this time are classified into groups according to their uses. That is, the applications created by the user can be classified into groups having different purposes for each function. Here, since the work performed by the user is often concentrated in the group unit, the function POU is managed in the group unit.

For example, in the application program 6 of FIG. 1A, POU1 (logic maximum setting) is managed by group 1, and functions POU2 and 3 are managed by group 2 (variable maximum setting). Here, among the classified groups, those having a functional POU larger than a predetermined threshold value are classified as a dedicated group for each functional POU. For example, if the size of the functional POU3 in FIG. 1A is larger than the threshold value, it can be classified as a dedicated group different from the functional POU2.

Then, the generated application program 6 is transferred to the PLC 2 via the Ethernet 6 (S06), and the operation is started (S07). At this time, since the PLC2 is duplicated, it is copied from the master to the slave, and if there is an abnormality in the master, the slave is instantly switched to the master side.

However, an online change equalization filter 14 that defines a portion that is not copied from the application file 6a on the master side to the application program 6b on the slave side is prepared. The online change equalization filter 14 distinguishes between a part where data can be copied from the master to the slave and a part where the data cannot be copied, and defines the latter part. The information defined here is described in the equalization filter information 13g. The content of the part defined in the online change equalization filter 14 is different for each function POU.

Further, while the PADT 4 is operating in the online change mode (S08, S09), a mark is added to the modified / added function POU and the variable addition / change / initialization information 13f. At this time, for the variable definition such as a structure having a large size, the addition / change / initialization information 13f may also be large. Therefore, from the viewpoint of processing speed, a mark is added to the change / equalization map 13h so that the parts such as corrections and additions can be understood in bit units. For example, a bit index in units of 2 bytes can be used.

When the addition / change initialization information 13f and the change / equalization map 13h are marked in this way and the download (S10) of the addition / correction portion to the PLC2 is completed, the marks are deleted. Even if the download is not executed, the marks are similarly erased even when the build is performed in the normal mode of PADT4.

≪Action effect≫
(1) Even if an existing large function POU of several Kbytes is attached to the user's application, it can be changed online.

In the past, minor changes such as ladders and changes in setting values could be changed online, but if the program to be replaced was many times the size of the original program, it could not be replaced.
That is, although online change is possible even with the conventional technology, since it is necessary to have a free area in the memory in advance, the whole becomes bloated, so the size of the POU that can be changed is several tens of bytes. Was limited to.
On the other hand, the function POU is classified into groups so that changes can be managed in group units, POU units, and variable units, and the group that makes additional changes easily by several Kbytes in advance has a fixed length of the maximum size as a whole. By making it possible to create, it is possible to change online even for large parts.

(2) Data equalization processing is restricted by the online change equalization filter 14 and the change / equalization map 13h, and online changes during redundant operation can be performed safely and at high speed. Also, by making the parameter part of the function POU a global variable, the address of the variable is fixed and can be safely changed online.

(3) By making the parameter part of the function POU a global variable, although the programming effort increases, the part automatically generated by the instrument creation support tool 5 increases, so the total programming cost should be kept low. Can be done.

1 ... System 2 ... PLC
3 ... Computer 4 ... PADT
5 ... Instrument creation support tool 6 ... Application 7 ... Ethernet 11a ... Management CPU
11b ... Program memory 11c ... Data memory 12 ... Task unit Instance area 13 ... Variable definition 13a ... General variable definition 13b ... Large variable definition over a certain size 13c ... Type information 13d ... Initial value 13e ... Current value 13f ... Addition / change / Initialization information 13g ... Equalization filter information 13h ... Change / equalization map 14 ... Online change equalization filter

Claims (2)

It is a method of managing the memory of a programmable logic controller that controls a task configured by a POU (Program Organization Unit).
A classification management step in which the POUs are classified into groups according to usage and managed in units of the classified groups.
Among the groups classified in the classification management step, if the size of the POU is larger than the size of the predetermined threshold value, the group classification step of classifying into a dedicated group and the group classification step.
If there is an online change to add or change the POU or variable during the operation of the programmable logic controller, a marking step to mark the addition / change / initialization information of the variable definition in the instance area corresponding to the POU, and the marking step.
If the programmable logic controller is duplicated to the master / slave, the online change equalization filter step that defines the part that is not copied from the master to the slave in the variable definition, and
A memory management method for a programmable logic controller, characterized by having. In the marking step,
The memory management method for a programmable logic controller according to claim 1, wherein the programmable controller erases each mark when the data of the added / changed portion is acquired.

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