JP4853370B2 - Programmable logic controller and programmable logic controller memory management method - Google Patents

Description

  The present invention relates to a programmable logic controller and a programmable logic controller memory management method, for example, a memory management method.

  Nowadays, the operation of the controller is generally controlled by a dedicated program (for example, Patent Documents 1 and 2). For example, the language of the program is based on the IEC (International Electrotechnical Commission) 61131-3 standard.

  It is also known that it is difficult to change a program in a PLC (Programmable Logic Controller) programmed by the language during the operation.

  Here, a general PLC memory management method will be described below with reference to FIG. FIG. 4 is a conceptual diagram showing a memory space in a general PLC.

  Usually, the program in the PLC is configured by a POU (Program Organization Unit) indicated by reference numeral 1 in FIG.

  The POU 1 includes an algorithm (ie, program code) 1b, a variable definition 1a used in the algorithm 1b, and an area for storing an instance corresponding to the variable definition 1a in the POU 1 (hereinafter referred to as an instance area) 1d. , A storage area (namely, memory) of the PLC has an area (hereinafter referred to as an instance storage area) 1c for storing the instance area 1d. That is, each POU has an instance storage area, and further, an instance area corresponding to the variable definition is provided in the instance storage area. Generally, there may be a plurality of instance areas for one POU for each application.

  A task exists in the execution unit of the program, and an arbitrary POU can be registered and executed in the task.

  For example, when the program is changed, the address of the instance area 1d (or instance storage area 1c) of the POU 1 may be changed, which makes it difficult to change the program online.

A feature of programming in the language is that the user is not aware of the address of the location of the instance area. However, in order to change the running program, it is necessary to check the instance area of the running program and to place the instance area of the new program for the change in an area that is not used by the existing program. .
JP-A-10-207512 (paragraphs [0020] to [0026] etc.). JP 2001-142510 (paragraphs [0023] to [0028] etc.).

  In order to change the program as described above online, it is necessary not to change the contents and address of the instance area in which the instance used to execute the program is stored.

  For example, when a program (i.e., POU) is added to the PLC, the instance capacity to be used is increased by the added POU. Therefore, if there is no free area for the instance area corresponding to the POU, online change cannot be performed.

  In order to cope with the addition of the program as described above, for example, as shown in FIG. 5, when the POU is created, the size of the instance storage area 1c is set in advance (ie, a predetermined free area; for example, in FIG. There is also a PLC that has a free area f1).

  However, the free area f1 as described above generally has a capacity of several W (Word) to several tens of W for each POU, and the program cannot be changed to exceed this capacity.

  The present invention has been made based on the above problems, and provides a programmable logic controller and a programmable logic controller memory management method for managing an instance storage area of a POU for each task in order to secure an instance area of the POU to be added. There is to do.

In order to solve the above problems, the present invention provides an instance storage area in a memory of a programmable logic controller for each task configured by a POU, and the instance area of the POU is allocated to the POU instance area. A programmable logic controller that is placed and managed in an instance storage area , wherein the programmable logic controller submits position information of an empty area in the instance storage area, and an instance area of the POU to which the programmable logic controller is added Means for receiving the position information of the POU, and means for securing the instance area of the added POU in the free area existing in the instance storage area based on the position information of the instance area of the added POU. characterized in that it comprises a To.

The invention according to claim 2 includes means for securing an extended instance storage area independently of the instance storage area and allowing the added POU to access the extended instance storage area in the invention according to claim 1. Features.

According to a third aspect of the present invention, an instance storage area is secured in the memory of the programmable logic controller for each task configured by the POU, and the instance area of the POU is placed in the instance storage area for management. The programmable logic controller submits position information of an empty area in the instance storage area, receives position information of an instance area of the POU to which the programmable logic controller is added, and Based on the position information of the instance area, an instance area of the added POU is secured in a free area existing in the instance storage area .

According to a fourth aspect of the present invention, in the third aspect of the present invention, an extended instance storage area is secured independently of the instance storage area, and the POU to be added is made to access the extended instance storage area. .

  According to the first and fourth aspects of the present invention, the POU instance areas can be integrated.

  According to the second and fifth aspects of the present invention, the position of the instance area of the POU to be added can be specified precisely.

  According to the third and sixth aspects of the invention, an independent instance storage area can be secured.

  As described above, according to the first and fourth aspects of the invention, the instance storage area can be managed for each task.

  According to the second and fifth aspects of the invention, the instance storage area can be used without waste.

  According to the third and sixth aspects of the invention, POU addition can be performed without affecting the operating PLC (or the program in the PLC).

  These can contribute to the field of PLC.

  Hereinafter, a programmable logic controller and a programmable logic controller memory management method according to first to third embodiments of the present invention will be described in detail with reference to the drawings.

  In the first to third embodiments of the present invention, the POU instance storage area is secured for each task in the PLC memory, and the POU instance area is placed in the instance storage area. A programmable logic controller and a programmable logic controller memory management method.

  First, an apparatus configuration when changing the PLC program in the first to third embodiments will be described with reference to FIG.

  A programming and debugging tool (PADT) 10 and the PLC main body 11 in FIG. 6 are connected by a communication line (or transmission line) 100, and a program in the PLC main body 11 is changed according to an instruction from the PADT 10.

  Next, the configuration of the PLC main body in the first to third embodiments will be described with reference to FIG.

The PLC main body 11 in FIG. 7 controls each device in the PLC main body 11 and corresponds to a management CPU (Central Processing Unit) 11a that communicates with the PADT 10, a program memory 11b that stores and manages the POU, and each POU. A data memory 11c having an instance storage area is provided. For example, the instance storage area corresponding to POU1 in Figure 7 instance storage area i _1, instance storage areas instance storage area i _n that corresponds to POU2 in FIG instance storage area corresponding to POUn in FIG. 7 an instance storage area i _2.

[First Embodiment]
The first embodiment is a programmable logic controller and a programmable logic controller memory management method that secures an instance storage area for each task.

  When an instance storage area is secured for each POU, an empty area is generated in each POU, and the empty area tends to become a useless area. Therefore, when changing the program, paying attention to the fact that the change is often performed in units of tasks (that is, a collection of POUs), and by integrating the instance storage areas allocated for each POU in the task, Integrate each free area to avoid creating a useless area.

  That is, the first embodiment is characterized in that the instance area is not managed in units of POUs but managed in units of tasks.

  The first embodiment will be described below with reference to FIG. FIG. 1 is a conceptual diagram showing a memory space in the PLC according to the first embodiment.

  First, it is assumed that one task is constituted by POU1 and POU2 in FIG. Furthermore, it is assumed that an instance storage area D1 corresponding to the task is secured in a storage device (that is, a memory) of the PLC. That is, the instance storage area is secured in the memory by the PLC when one task is generated.

  For example, when an area is secured in the memory by the PLC, the start address and end address of the area are registered in the PLC. When the POU in the task gives an access instruction to the area from the PLC, the start address and the end address are referred to and the area is accessed.

  The POU1 and POU2 design (ie, program) the algorithms 1b and 2b so that the instance area d1 in the instance storage area D1 can be accessed. For example, as the programming described above, an offset from the start address of the instance storage area to a desired instance area may be set in the variable definition in the POU.

  For example, a method of accessing an instance of the POU from the POU using the offset as described above is as follows.

  First, the PLC secures an instance storage area for each task in a memory of the PLC at a predetermined position and size.

  Next, the POU instructs the PLC to access the instance of the POU based on the offset in the variable definition.

  Next, the PLC causes the POU to access the instance area in the instance storage area based on the address obtained by adding the offset to the start address of the instance storage area.

  For example, when a POU 3 in FIG. 1 is newly added to the task, a new instance area of the POU 3 is secured in the empty area f2 in the instance storage area D1.

  According to the first embodiment as described above, the instance area related to the program change (ie, POU addition) can be easily secured from the free area in the instance storage area for each task.

  For example, if 1 KW (KiloWord) can be secured in advance as a free area, online change within 1 KW can be performed. Usually, about 1 KW is sufficient for a general program change.

[Second Embodiment]
The second embodiment of the present invention is a programmable logic controller and a programmable logic controller memory management method that designates position information of an instance area and secures the instance area.

  As a premise of the second embodiment, it is assumed that there is an empty area (that is, an unused area) in the instance storage area reserved for each task. Under the premise, in the second embodiment, when a new instance area is secured in the empty area, the position information of the new instance area is designated and secured.

  Note that the position information of the area is expressed by, for example, the start address or the end address, and preferably the size of the area.

  The second embodiment will be described below with reference to FIG. FIG. 2 is a conceptual diagram showing a memory space in the PLC according to the second embodiment.

  First, it is assumed that POU1 and POU2 in FIG. 2 use the instance storage area D1.

  An example of a procedure for adding the POU 3 in FIG. 2 to the PLC is as follows.

  First, the PLC is instructed to acquire the position information of the free area. Note that the instruction method may be, for example, an instruction method by communication (ie, a command or the like) from a terminal connected to the PLC.

  Next, the PLC submits position information of the empty area f2. The submission method may be, for example, a method in which the PLC submits the position information through communication to a terminal connected to the PLC.

  Next, the POU 3 is created based on the position information of the free area f2 so that the POU 3 can access the free area f2.

For example, an offset from the start address of the instance storage area D1 to the instance area of POU3 is determined so that the instance area of the POU3 fits in the empty area f2, and the offset is set in the variable definition 3a in the POU3. The POU 3 is created as follows.

  Next, the position information of the instance area of the POU 3 is designated for the PLC, and the POU 3 is newly added to the PLC. The designation method may be, for example, a method of instructing the PLC by including the position information in a command for adding a POU.

  Then, the PLC secures the instance area of the POU 3 in the free area f2 based on the position information of the instance area of the POU 3.

  According to the second embodiment as described above, the instance area can be secured at an appropriate position on the PLC memory.

[Third Embodiment]
The third embodiment is a programmable logic controller and a programmable logic controller memory management method that secures an independently expanded instance storage area.

  That is, the third embodiment is independent of the instance storage area when the free area in the instance storage area reserved for each task is insufficient (that is, the instance storage area is filled with instances). The instance storage area secured (or expanded) in (1) is secured and used to make up for the shortage.

  Note that one extended instance storage area is secured in the PLC storage device and can be used in common by each POU in the PLC.

  The third embodiment will be described below with reference to FIG. FIG. 3 is a conceptual diagram showing a memory space in the PLC according to the third embodiment.

  First, it is assumed that POU1 and POU2 in FIG. 3 use the instance storage area D1. Furthermore, it is assumed that the empty area f2 does not have a size necessary for the additional POU.

  When the POU 3 in FIG. 3 is added to the PLC, the POU 3 is created so that the POU 3 can access the extended instance storage area D2. For example, the POU 3 is created so that an offset from the start address of the extended instance storage area D2 to the instance area of the POU 3 is set in the variable definition 3a in the POU 3.

  The access method from the POU 3 to the extended instance storage area D2 is, for example, as follows.

  First, the PLC secures the extended instance storage area D2 in a memory of the PLC at a predetermined position and size.

  Next, the POU 3 instructs the PLC to access the instance of the POU 3 based on the offset in the variable definition 3a. The offset is an offset from the start address of the extended instance storage area D2 to the instance area of the POU3.

  Next, based on the address obtained by adding the offset to the start address of the extension instance storage area D2 (that is, the start address of the instance area), the PLC sends the POU to the extension instance storage area D2. To access.

  According to the third embodiment as described above, since the extended instance storage area D2 is independent of the instance storage area D1, online change (for example, without affecting the instance storage area) , POU addition to PLC).

  Although the present invention has been described in detail only for the specific examples described above, it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the technical idea of the present invention. Such variations and modifications are naturally within the scope of the claims.

  For example, the position information in the second embodiment may be expressed by an offset from the start address of the instance storage area, and preferably in addition to them, the size of the area. That is, the offset is converted into an address based on the start address of the instance storage area by the PLC.

The memory space conceptual diagram in PLC in the 1st Embodiment. The conceptual diagram of the memory space in PLC in the 2nd Embodiment. The conceptual diagram of the memory space in PLC in the 3rd Embodiment. The conceptual diagram showing the example 1 of the memory space in a general PLC. The conceptual diagram showing the example 2 of the memory space in general PLC. The apparatus block diagram at the time of the program change of PLC. The block diagram of the PLC main body.

Explanation of symbols

1, 2, 3, n ... POU
1a, 2a, 3a ... Variable definition 1b, 2b, 3b ... Algorithm (program code)
1c: Instance storage area in POU units 1d: Instance area in POU units 10: PADT (Programming And Debug Tool)
11 ... PLC main body 100 ... Communication line (or transmission line)
11a ... Management CPU
11b ... Program memory 11c ... Data memory f1 ... Empty area in POU units f2 ... Empty area in task units d1 ... Instance areas in task units i ₁ , i ₂ , i _n ... Instance storage areas D1 ... Instance storage areas in task units D2 ... Extended instance storage area

Claims (4)

A programmable logic controller that secures an instance storage area in a memory of a programmable logic controller for each task configured by the POU, and manages the instance area of the POU in the instance storage area ,
Means for the programmable logic controller to submit location information of an empty area in the instance storage area;
Means for receiving location information of an instance area of a POU to which the programmable logic controller is added;
Means for securing an instance area of the added POU in a free area existing in the instance storage area based on position information of the instance area of the added POU;
Programmable logic controller, which comprises a. 2. The programmable logic controller according to claim 1 , further comprising means for securing an extended instance storage area independently of the instance storage area and causing the added POU to access the extended instance storage area. A programmable logic controller memory management method for securing an instance storage area in a memory of a programmable logic controller for each task configured by a POU, and managing the POU instance area in the instance storage area ,
The programmable logic controller submits position information of an empty area in the instance storage area,
Receiving position information of an instance area of the POU to which the programmable logic controller is added;
Based on the location information of the instance area of the added POU, the instance area of the added POU is secured in the free area existing in the instance storage area.
A programmable logic controller memory management method. 4. The programmable logic controller memory management method according to claim 3 , wherein an extended instance storage area is secured independently of the instance storage area, and the added POU is accessed by the added POU.

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