JP2003271209A - Control device, expansion device and programming tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a PLC capable of executing data link even if the PLC corresponds to a program using physical address. <P>SOLUTION: This PLC comprises a communication interface 11 which exchanges data between other control devices via a network 20, a data link area 16 which stores a net variable obtained by a communication I/F, an MPU 12 which executes a user program, and a data memory 15 which is accessed by the MPU while executing an operation. The address information of the data link area 16 storing the net variable shared with other PLCs is stored into the memory area of the data memory which is referred to based on the physical address described in the user program, and the access to the data link area is enabled based on the address information. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device, an extension device and a programming tool.

[0002]

2. Description of the Related Art In the field of factory automation, a plurality of control devices such as programmable controllers (PLCs) are connected to a network, and the plurality of control devices share input / output data used for sequence control while coordinating and synchronizing. Control may be executed. In that case, in order for each control device to share the input / output data (I / O data), the switch or sensor of the source of each I / O data is physically connected to each control device, or the data is transmitted. A user program for sharing may be used.

Another method for sharing data among the control devices is called a data link method. This data link method is a method for cyclically exchanging (linking) data between I / O memories provided in each of a plurality of control devices so as to have common data. That is, by exchanging the contents of the I / O memory tables of the control devices with each other at a certain timing and fetching the I / O data of the other control device into the I / O memory of the own device, the other control device and the own control device are controlled. Data can be shared with the device. At this time, even if the memory allocations of the control devices are different from each other, it is sufficient to always specify a predetermined memory address (physical address). The designation of the memory address is collectively set in advance by an external setting device called a tool.

However, the above-mentioned conventional method has the following problems. That is, in the former method using the user program, it is necessary to embed the communication logic in the ladder program for operating the control device (PLC), which complicates the user program development and also makes maintenance difficult.

In the latter case of the data link method, the address setting itself becomes complicated due to the allocation of memory areas when linking data. On the other hand, since the ladder program of each control unit is designed to access by directly specifying the memory address, if the allocation of the memory area is once set and then the allocation of the memory area is changed, the user program (Ladder program) needs to be rewritten and becomes complicated.
Moreover, when a new control device is added to the network, the reallocation of the memory area and the accompanying change of the user program extend to the existing user program installed in the control device already connected to the network, and the system. There was a problem that I had to stop.

In order to solve such a problem, for example, there is an invention disclosed in International Publication Number (WO01 / 27701). As one example of the present invention, the network global variables (hereinafter, referred to as “net variables”) are used to connect the control devices, and the control devices automatically perform reference resolution of the net variables. The control program developed by using different programming tools stored for each can be easily integrated as a system.

That is, a logical name of data shared by a plurality of nodes connected to a network is defined, the shared data is stored and held in a predetermined storage area of the storage unit of the node, and the logical name and The related information associated with the storage position information of the storage unit that stores the data corresponding to the logical name is stored and held in the related information storage unit, and between the plurality of nodes, the logical name and the related information based on the related information. When the shared data is sent and received, and the state of the node of the communication partner changes, when the change affects the related information, the related node is linked without stopping the processing of the node connected to the network. I am trying to change the information.

The data sharing function based on net variables is based on a programming model in which the concept of variables exists like IEC61131-3. In this programming model, users program with variables and are unaware of which address in memory the variable is assigned.

[0009] With this, it is possible to access the shared data without being aware of the communication processing because the access can be made by the logical name without knowing the storage location information of the specific data.

[0010]

However, in the conventional PLC program, the concept of variable does not exist. Although some programming tools support variables, even in that case, it is necessary for the user to assign the variable to the physical address, and the variable name and the physical address are fixedly associated with each other. Therefore, it has not been possible to bring into the program such as a net variable whose correspondence with other PLC data is dynamically determined by the system.

According to the present invention, even a PLC corresponding to a program using a conventional physical address can perform a data link by utilizing an indirect reference function, and the reference destination of the data link area is changed. It is an object of the present invention to provide a control device, an expansion device, and a programming tool that can be easily modified according to a system change without affecting the original program.

[0012]

A control device according to the present invention is a control device capable of sharing data with another control device connected to a network, and the other control device via the network. A communication unit for exchanging data with the device, a data link area for storing the shared data obtained by the communication unit, an arithmetic processing unit for arithmetically executing a user program, and an arithmetic processing unit executing an arithmetic operation. A data memory for accessing the data link area, and storing address information of the data link area in which the shared data is stored in a storage area of the data memory that is referred to based on a physical address described in the user program. The data link area can be accessed based on the address information. The address information of the data link area may be a specific address or an offset. Further, the control device is realized by the PLC according to the present embodiment.

The extension device according to the present invention is an extension device for a control device which can share data with another control device connected to a network, and is incorporated in the other control device. Based on the information acquired by the name resolution means and the information acquired by the name resolution means by directly or indirectly communicating with the extended device The data memory further comprises a data link address setting means for setting address information of the data link area in which the shared data is stored.

Here, the expansion device is the PL in the embodiment.
Although it is an expansion unit that is a separate unit from the main body of C,
The present invention is not limited to this, and may be, for example, an expansion board or one created as a program product.

Further, the programming tool according to the present invention is a programming tool for creating a program to be downloaded to a control device, which is a logical name of data shared among a plurality of control devices and data referenced by a user program. Based on the acquisition means for acquiring the physical address of the memory and the information acquired by the acquisition means,
A variable database in which the logical name, the physical address, and an area for storing address information of a data link area for storing the shared data are associated with each other is created and configured to be stored in a storage device. The acquisition unit may be, for example, an input device for inputting data or a unit for reading out already registered data.

According to the present invention, the programmed user program or the like describes the physical address of the data memory when referring to the data shared by the plurality of control devices via the network. The data memory area specified by this physical address stores address information for accessing the data link area in which the data to be referred to is stored. Therefore, in the user program or the like, the data link area can be referred to based on the value (address information) stored in the data memory by indirectly specifying the address together with the physical address.

Therefore, even the PLC corresponding to the program using the conventional physical address can perform the data link by utilizing the indirect reference function. Further, when the address of the data link area for storing the shared data is changed, the value stored in the data memory area specified by the physical address of the data is changed to the changed value, thereby making the user program etc. Can access shared data whose address has been changed without change.

Further, it is preferable to have a function of generating a program including a plurality of instructions for indirect reference when receiving a conversion instruction including at least a physical address of a data memory of a reference destination. With such a function, it is possible to write a program that automatically makes an indirect reference, but the present invention does not necessarily have to have such a function.

[0019]

FIG. 1 is a diagram showing an example of a network system to which the present invention is applied. As shown in FIG. 1, a PLC 10, which is a control device, is connected to a network 20, and by transmitting and receiving data to and from each other, it is possible to execute cooperation / synchronization control while sharing data (data link).

The PLC 10 is basically the same as the conventional one, and includes a communication interface 11 for connecting to the network 20 for transmitting and receiving data, an MPU 12 for performing arithmetic operations according to a system program and a user program stored in the ROM 13, The MPU 12 is provided with a memory 14 used as a work area for execution of calculation,
They are connected via a bus. In addition, the memory 14 is shared between the data memory 15 that stores I / O data and other information about external input / output devices managed by the PLC 10 and another PLC 10 that is connected via the network 20. The data link area 16 for storing the data to be set is set.

The PLC 10 is constructed by appropriately connecting units formed for each function, and the one shown in the drawing corresponds to a so-called CPU unit. Various things such as / O unit can be connected. The communication interface 11 can also be configured as a separate unit such as a communication unit.

A programming tool 25 is also connected to the network 20, and a user program or the like generated by the programming tool 25 can be downloaded to a predetermined PLC 10 via the network 20. Of course, programming tool 2
The 5 may be directly connected to the PLC 10 instead of via the network 20 in this way.

Here, in the present invention, the allocation of data to the data memory 15 and the data link area 16 is appropriately set, and the indirect reference function which is the existing function of the PLC is used, so that the programming can be performed using physical addresses. It was possible to access the net variable while using it.

As is well known, the indirect reference function is one of program access methods, and when indirect reference using an index register is specified, the indirect reference function is stored not in the memory specified by the address but in the memory. Value is interpreted as an address in memory, and the memory pointed to by that address is accessed. In other words, normally, the value stored in the memory area specified by the physical address described in the program is processed such as reading and writing, but by using the indirect reference function, the actual processing target value is , A memory area specified by the value stored in the physical address described in the program.

As an example, as shown in FIG.
When the address of is accessed indirectly, the 018200 contained therein is interpreted as an address, the address of 01820 is accessed, and a value of 36 is obtained. Therefore, by changing the value stored in the address of 00100, the actual reference destination address can be changed even in the same program.

Utilizing this fact, in the present embodiment, as shown in FIG. 3, the data link of the indirect reference destination is linked to the memory area of the data memory 15 specified by the physical address (00100) specified by the user program. A value (100) that specifies the address of area 16 is stored. Then, as described above, the relevant physical address (00100)
In contrast, when accessed by indirect designation, the data link area 1010 is calculated based on the value (100) contained therein.
Access address 0 and store 23
You can get a value of 4.

In this embodiment, the data link area 16 is allocated from the address 10000,
The value for specifying the address of the data link area 16 stored in the data memory 15 is an offset value from the start address (10000). Therefore, as shown in the figure, the physical address (001
If the value stored in 00) is "100", the address of the data link area is 10100, which is obtained by adding 100 to the start address.

The data link area 16 is a memory for storing data which is logically shared via the network 20, and its data structure is, for example, as shown in FIG.
As shown in. That is, the same logical name is
Since it exists only on the network and is shared by each PLC (control device), processing such as updating of data for a certain logical name is performed by a certain PL on the network.
C10 has the authority to execute, and other PLCs 10
The data sent from one PLC 10 will be acquired. That is, the data about a certain logical name has the function of the one PLC 10 updating the data,
It has a function of giving it to another PLC 10.

Therefore, as shown in the figure, the own node area for storing the data about the logical name (publicized logical name) having the above-mentioned function of updating and the original data is stored in the other PLC 10. For other logical names, there is another node area that stores a copy of that data. In the present embodiment, the data link area 16 is divided for each node in order to improve the data transfer efficiency, but the present invention is not limited to this.

Furthermore, the same shared logical name (variable name)
The offset value in the area for storing the data (variable data) is common to all nodes. That is, when the variable data x for a certain logical name X is stored by a predetermined size from the offset value N of the own node area of the node (1), it is stored at a predetermined position in the other node area in another node. It will be. Then, this storage position is stored in an area of a predetermined size from the offset value N of the other node area for the node (1). In other words, when storing the variable data that is published by another node that is required by itself in the other node area of the own node, the same offset value as the offset value from the beginning of the own node area in the other node that is published is stored. Will be stored. In this way, by matching the offset value in each node area between the public side and the user side, various processes for maintaining data sharing can be easily performed.

Regarding the actual transmission / reception of data, the PLC 10 having the above-mentioned function may output the data.
The other PLC 10 may read and acquire the data from the PLC 10 having the original data.

The data link area 16 is
Data is read and written between the PLCs 10 at a predetermined timing, and data sharing is maintained. Note that since a known technology such as the invention disclosed in International Publication WO01 / 27701 can be applied to a data sharing processing algorithm involved in a specific data transfer processing, detailed description thereof will be omitted.

As a result, the user accesses the data memory 15 by using the indirect reference function of the conventional PLC by describing the physical address in the memory assigned to the net variable and programming it. Even in a program that describes a physical address, data access to a net variable is possible.

Further, in order to easily execute the above-mentioned processing, in the present embodiment, as shown in FIG. 1, the programming tool 25 has a net variable name setting section 26 for setting a net variable name and its net variable. A variable database 27 that stores the information set by the name setting unit 26 is provided. In addition, the PLC 10 is provided with an expansion unit 17 for dealing with a net variable at the time of data linking. The extension unit 17 includes a name resolution unit 18 and a data link address setting unit 19.

First, the net variable name setting unit 26 associates a logical name with a net variable. That is, in the case of a net variable, since the logical name is associated with the data of another PLC 10, it is necessary to associate the net variable name (logical name) with the indirectly designated address.
Then, the net variable name setting unit 26 performs such association. Specifically, first, the correspondence setting screen as shown in FIG. 5 is displayed, and the user operates the input device of the programming tool 25 to input the corresponding data to the corresponding portion. Received data.
Then, the input in which "OK" is selected is accepted. That is, the user operates the input device of the programming tool 25 to set the address, the net variable name (logical name), the type,
After inputting the corresponding data in the input / output distinction fields, click the "OK" button on the screen.
These data are received in association with each other, and a variable data file is created and stored in the variable database 27.

The data structure of the variable database 27 is, as shown in FIG. 6, "logical name", "type",
"Size", "I / O attribute", "Memory address"
And a "static name resolved flag", a "data link area offset" and a "bit position" are associated with each other. Here, "size" is the data size of the information about the logical name, and "input / output attribute" is
It is used to specify the transmission / reception direction of the data specified by the logical name.

That is, if the input / output attribute is "output",
This means outputting the information related to the logical name stored in that node (PLC) to another node. Then, data about the logical name whose input / output attribute is output is stored in a predetermined area of the own node area of the data link area 16.

When the input / output attribute is "input", it means that the information about the logical name used in the node is acquired from another node. Then, the data about the logical name whose input / output attribute is input is stored in a predetermined area of the other node area of the data link area 16.

The "memory address" stores a physical address for specifying the position of the data memory 15 where the actual data for the logical name is stored. These data are created based on the data input on the correspondence setting screen (FIG. 5).

The static name resolved flag is a flag indicating whether or not the variable data for this logical name can be indirectly referenced in the actual PLC 10, and its initial value is "FALSE". . The data link area offset is a value corresponding to “100” stored in the data memory 15 in FIG. 3, and specifies the address on the data link area 16 in which the variable data specified by the logical name is stored. Stores the offset value for Also in this case, the initial value is "0".

Then, the variable data file stored in the variable database 27 is downloaded to the PLC 10 and allocated to the data memory 15 or the like according to this variable data file. The structure of this downloaded variable data file is basically as shown in FIG.
It is similar to that shown in FIG. 1, and is stored in the memory 14 of the PLC 10, for example. Alternatively, it may be held on the side of the expansion unit 17.

The allocation processing is performed by the name resolution section 18 and the data link address setting section 19 of the expansion unit 17. That is, the name resolution unit 18 determines from the input / output attributes whether the management of the net variable defined by each logical name is for itself (own node) or another node, and the own node (outputs the input / output attribute). In the case of), the data link area 16 is allocated to a predetermined area of its own node area. That is, the offset value of the memory address that specifies the predetermined area is registered in the column of the data link area offset of the variable data file. Further, the set information (logical name, node number identifying itself, data link offset value, etc.) is disclosed to the name resolution unit 18 of another PLC 10 connected to the network 20.

On the other hand, when the net variable to be handled is another node (input / output attribute is input), information published about the net variable (PL having authority for the net variable)
The name resolution unit 18 of C10 obtains (output) and registers the offset value in the column of the data link area offset of the variable data file. As a result, the data link area offset value corresponding to the logical name of the variable data file is stored, the physical address (memory address) is associated, and the name resolution processing is completed. Along with this, the static name resolved flag is changed to TRUE.

Then, the name resolution unit 18 executes the above-described name resolution processing at a predetermined timing, for example, when a new PLC is added to the network or when it is removed. In addition, as a method of acquiring information of other nodes, the name resolution unit 18 of each PLC 10 sequentially obtains information about the net variables for which it has the authority for all PLCs.
Each PLC 10 that has transmitted to and received it can be realized by incorporating the contents only when the PLC 10 refers to itself. In addition, the name resolution unit 18 of each PLC 10
However, if there is a net variable of another node that it wants to refer to, it notifies that fact and receives the corresponding PLC.
10 (PLC 10 with the net variable as its own node)
However, various methods such as returning information about the net variable can be taken.

On the other hand, the data link address setting section 19
Extracts the one in which a concrete offset value is stored in the column of the data link offset area of the variable data file, acquires the memory address (physical address) of the corresponding data memory 15 and The acquired offset value is stored in the memory area specified by the physical address. As a result, the data memory 15 and the data link area 16 are associated with each other, that is, the programmed physical address and the address of the reference destination (data link area 16) in which the actual value is stored are associated with each other.

Further, the data link address setting section 19
When the process of registering the offset value in the data memory 15 is completed, changes the static name resolved flag to TRUE for the corresponding net variable (logical name). Therefore,
The offset value is registered in the data link area offset, and the static name resolved flag is FALS.
The E data is extracted and registered in the data memory 15.

In the above example, the data link of the net variable is realized by the indirect reference of the data memory, but it can also be realized by the indirect reference method using the index register supported by the conventional PLC. That is, the name resolution unit 18 shown in FIG. 1 sets the address (offset from the head of the data link area) of the data link area 16 corresponding to the net variable determined by the name resolution processing to a predetermined area of the data memory 15. The address of the memory storing the offset is stored in the index register IR for access. That is, for example, the program for storing the value of the net variable in D00200 of the data memory is as shown in FIG.
Can be described as shown in. Here, “10000” described in the first line is the start address of the link data area 16. In contrast to the above, when the value of the data memory D00200 is stored in the net variable, it becomes as shown in FIG. 7 (b).

By the way, as described above, it is of course possible for a user to directly write a program that enables access to a net variable while designating it by a physical address.
By preparing a conversion command for creating a program composed of a plurality of such commands, the user can describe the conversion command by using such a conversion command, and from a plurality of lines (multiple commands). There is no need to enter the program that becomes.

As an example, as shown in FIG.
An instruction (conversion instruction) called "GETNETV storage destination address net variable address" (both the storage destination address and the net variable address are physical addresses on the data memory) is prepared. And this "GETNETV"
Is described, the programming tool 25 displays
It is preferable that the program including a plurality of instructions as shown in (b) is automatically expanded and downloaded to the PLC 10 because the user's programming work can be saved. The example shown in FIG. 8 corresponds to the system using the index register described in FIG.

[0050]

As described above, according to the present invention, since the address information for specifying the reference destination of the data link area is stored in the storage area of the data memory, the PLC corresponding to the program using the physical address is used. However, the indirect reference function can be used to perform the data link, and even if the reference destination of the data link area is changed, the system can be easily changed without affecting the original program.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a network to which the present invention is applied.

FIG. 2 is a diagram illustrating an indirect reference function.

FIG. 3 is a diagram showing an example of a data structure of a memory.

FIG. 4 is a diagram showing an example of a data structure of a data link area.

FIG. 5 is a diagram showing an example of a setting screen for registering information regarding net variables in a programming tool.

FIG. 6 is a diagram showing an internal structure of a variable database.

FIG. 7 is a diagram illustrating another embodiment.

FIG. 8 is a diagram illustrating an example of a function of a tool.

[Explanation of symbols]

10 PLC 11 Communication interface 12 MPU 13 ROM 14 memory 15 data memory 16 Data link area 17 Expansion unit 18 Name Resolution Department 19 Data link address setting section 20 networks 25 programming tools 26 Net variable name setting part 27 variable database

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Claims (4)

[Claims] 1. A control device capable of sharing data with another control device connected to a network, the communication for exchanging data with the other control device via a network. Section, a data link area for storing shared data obtained by the communication section, an arithmetic processing section for arithmetically executing a user program, and a data memory accessed by the arithmetic processing section during arithmetic operation, Address information of the data link area in which the shared data is stored is stored in a storage area of the data memory that is referred to based on a physical address described in a program, and the data link area is based on the address information. A control device characterized by being configured to be accessible to. 2. An extension device for a control device capable of sharing data with another control device connected to a network, which is directly or indirectly with the extension device incorporated in the other control device. Based on the information acquired by the name resolution means, the name resolution means for performing information communication to obtain information about the shared data, and the shared data in the data memory designated by a physical address for the shared data. Data link address setting means for setting address information of the data link area in which the data to be stored is stored. 3. A programming tool for creating a program to be downloaded to a control device, the acquiring means acquiring a logical name of data shared between a plurality of control devices and a physical address of a data memory referred to by a user program. And the logical name based on the information acquired by the acquisition means,
A programming tool comprising means for creating a variable database in which the physical address and an area for storing address information of a data link area for storing the shared data are associated and stored in a storage device. 4. The apparatus according to claim 3, further comprising a function of generating a program including a plurality of instructions for indirect reference when receiving a conversion instruction including at least a physical address of a reference data memory. Programming tools.