JP2006050023A - Node - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a programmable logic controller (PLC) which can easily manage data link areas and can simply add the data link areas. <P>SOLUTION: A node includes a data link function for transmitting and receiving shared data, to be shared among PLC's 10 connected to a network 20. The IO memory 11f of the PLC has a plurality of types of memory areas, such as contact area for storing contact information, data memory area for storing the information of a plurality of bytes. A plurality of the data link areas, each for storing the data to be shared, can be set in the same memory area (DM area, in the example shown). Consequently, another data link area can be added to the memory area already set with the data area. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a node, and more specifically to a node having a data link function for transmitting / receiving shared data to be shared with other nodes connected to a network.

  A PLC (programmable logic controller) that controls the FA (factory automation) system installed in a production factory (manufacturing site) is connected to input devices such as CPU units, sensors, and switches that execute calculations based on control programs. An input unit that captures these on / off signals as input signals, an output unit that connects output devices such as actuators and relays and sends output signals to them, a communication unit that connects to and exchanges information with host devices, etc. It is configured by combining a plurality of units such as a power supply unit that supplies power to each unit.

  Then, the PLC fetches the signal input from the input unit into the I / O memory of the CPU unit (IN refresh process), and performs a logical operation based on a pre-registered ladder language (program operation execution process). The operation execution result is written in the I / O memory, sent to the output unit (OUT refresh process), and then communicated with a higher-level terminal device or display connected to the network (peripheral service process). Repeat on click.

  By the way, in a system including this PLC, by preparing a plurality of master nodes such as PLCs and other controllers, by connecting the plurality of nodes via a network and sharing data among the respective nodes (masters), Synchronous control and cooperative control may be performed. In this case, as a method of sharing data between nodes such as PLCs, there is a data link method used between multi-masters.

  In this data link method, as disclosed in Patent Document 1, Patent Document 2, and the like, a data link area is set in a predetermined area of a memory in each node. In this data link area, a local node area for storing data to be shared and a remote node area for storing data sent from other nodes are prepared. These data link areas are set in a continuous memory area. Each node becomes a master node and transmits its own data stored in its own node area via the network. The transmitted data is acquired by all other nodes (masters) connected to the network, and stored in the corresponding other node areas (other node areas for the node that transmitted the acquired data). As a result, all nodes output data stored in their own node areas, so that all nodes participating in the data link can share data with other nodes. This data link function is widely used as a method of sharing data between nodes in a PLC network because data can be exchanged between a plurality of nodes (PLC) without creating a ladder program.

  By the way, normally, the memory of the programmable controller includes a relay area (contact area) that is contact information and a data memory area (data area) that is word data. The contact area is a storage area for storing input / output information in units of 1 bit by the input / output unit, and the data area is numerical data or code information of 2 bytes or more, which makes sense for the user in each data unit. This is an area for storing information.

  The types of data that need to be shared among the nodes include 1-bit unit input / output information stored in the contact area and information consisting of a plurality of bytes stored in the data area. Therefore, as shown in FIG. 1, conventionally, in a network system in which a plurality of PLCs 1 are connected to each area via a network 2, a data link area is provided for each contact area and data area of each PLC 1. Could be set.

  Here, in the figure, the hatched area is the own node area, and the white area is the other node area. Therefore, for example, paying attention to PLC (A), the local node data stored in the area A of its own contact area is transmitted to the network 2 by broadcast communication at a predetermined timing. Then, the PLCs (B) and (C) receive the data sent from the PLC (A) via the network 2 and store them in the area A in their contact areas. Similarly, the local node data stored in the area A of the data area is transmitted to the network 2 by broadcast communication. Then, the PLCs (B) and (C) receive the data sent from the PLC (A) via the network 2 and store it in the area A in their own data area. By transmitting the data in the respective node areas of the PLCs (B) and (C) in the same manner, each PLC can share data with other nodes.

On the other hand, as shown in FIG. 2, the data link area can be set at any position of the contact area and the data area. That is, the contact area and the data area naturally have an area for storing data used by itself without performing data link. Therefore, a memory area used as a data link area is set (secured) in advance using a tool or the like. The setting position of the data link area may be in the middle of the area as shown in FIG. 2A or at the end of the area as shown in FIG. 2B. Also good. However, regardless of the location, the data link area should be set to a continuous area for data management, ease of transfer work, and other reasons, and as shown in FIG. It has been customary that the area for storing data to be continuous is also continuous.
Patent No. 3329399 JP-A-10-164167

  As described above, allocating the data link area to the contact area and the data area is effective in managing according to the meaning of the data (whether it is meaningful as bit data or meaning as word data). . However, on the contrary, the degree of freedom of allocation of the data link area is lowered, and there are the following problems.

  That is, since the contact area and the data area are allocated separately from each other, if there is a need to share the contact information and data, data link areas are allocated to the contact area and the data area, respectively. . Then, since the data link area is distributed to two areas, the user is difficult to manage the memory area. In addition, since the areas are dispersed, there is a possibility that errors such as erroneous writing and erroneous reading due to a ladder program or the like may be induced.

  In addition, if data link data is to be increased later when data link has already been performed, only one data link area can be assigned to the same area, so data ring data cannot be added and expanded. There is difficulty in sex. For this reason, if a certain data link area is increased, the allocated address will change, so it is necessary to change the ladder program and the like.

  That is, when data link is performed in the memory allocation state as shown in FIG. 3A, when a request to increase the own node area set in the data memory of the PLC (A) by 50 ch occurs. Since the own node area of the PLC (A) needs to be continuous, the memory range from 100 to 200 needs to be expanded from 100 to 250 as shown in FIG. Along with this, the addresses of the storage areas of other node areas that are data-linked with the data of PLCs (B) and (C) are also shifted by the increment.

  Then, as shown in FIG. 4, for example, in PLC (A), when there is a program that takes data received from PLC (B) into the work area (W500), the transmission area of PLC (A) is increased by 50 CH. As a result, the reception start address from the PLC (B) shifts from 200CH to 250CH, so all the related ladder programs must be changed. That is, for example, it is necessary to change the program shown in FIG. 4 (a) to the program shown in FIG. 4 (b). Does not work properly.

  An object of the present invention is to provide a node capable of easily managing a data link area and easily adding a data link area.

  In order to achieve the above object, the node of the present invention has a data link function for transmitting and receiving shared data to be shared with other nodes connected to the network, and the node stores contact information. A plurality of types of memory areas including an area and a data memory area for storing information of a plurality of bytes are provided, and a plurality of data link areas for storing the data to be shared can be set in the same memory area.

  Since a plurality of data link areas can be set in the same (single) memory area, the user can centrally manage an area for exchanging data with other nodes on the network in one place (one area). it can. Therefore, it becomes easy to avoid erroneous writing or reading of data.

  As another solution, a data link function for transmitting and receiving shared data to be shared with other nodes connected to the network, the node includes a contact area for storing contact information, and a plurality of bytes A plurality of types of memory areas including a data memory area for storing information on the data, and another data link area can be additionally set in the memory area in which the data link area for storing the data to be shared is already set. .

  In this way, for example, when a data link area has already been set, and when another data to be shared is newly generated due to system expansion or other factors, the increase is added to the new data link area. By allocating to, it is not necessary to change the allocation of the original data link area. That is, the data link area can be increased without changing the existing ladder program.

  Each of the nodes described above includes a data link allocation table that stores information for specifying a storage area of the data link area, and accesses a predetermined storage area of the memory area based on the data link allocation table to store data. It is good to have a function to read and write. The node of the present invention corresponds to a PLC in the embodiment.

  In the present invention, management of the data link area can be easily performed, and addition of the data link area can be easily performed.

  FIG. 5 shows a preferred embodiment of the present invention. In this example, three PLAs 10 are connected via the network 20 and perform data links. Although not shown, the PLC 10 is configured by connecting a plurality of units. As an example of the unit, there are various types of paper hot water such as a power supply unit, a CPU unit, an IO unit, a communication unit, and a master unit. Focusing on the relationship with the present invention, that is, performing data ringing, a CPU unit 11 and a communication unit 12 are provided as shown in FIG. These units 11 and 12 are connected by a PLC interface 13 to transmit and receive data between the units.

  The CPU unit 11 is a unit that controls the entire PLC 10, and has a hardware configuration of an MPU 11a that is a microprocessor that controls the operation of the entire CPU unit 11, a ROM 11b that is a memory for storing system firmware, and a system work. Work RAM 11c. User memory (UM) 11d which is a memory for storing a user program, ASIC 11e which performs user program (command) execution processing / communication unit interface processing / memory access bus arbitration processing, and IO memory which is a memory area such as a contact area and a data area (IOM) 11f and a data-capable non-volatile memory 11g which is a memory for storing various settings and the like are connected to the internal bus 11h so that data can be transferred to each other via the internal bus 11h. It has become.

  The communication unit 12 includes an MPU 12a that is a microprocessor that controls the operation of the entire communication unit, a ROM 12b that is a memory that stores system firmware, and a work RAM 12c that is a memory used as system work. Furthermore, a communication interface 12d that connects to the external network 20 and communicates with other nodes is also provided. These are also connected to the internal bus 12e so that data can be transferred to each other via the internal bus 12e.

  Next, a function for performing a data link, which is a main part of the present invention, will be described. The data link area is allocated to a predetermined memory area in the IO memory 11 f of the CPU unit 11. This allocation is preset using a tool, and generates a data link allocation table (see FIG. 7) that specifies information relating to storing data of each node that is data-linked to which position of which area type, It is registered in the data storing nonvolatile memory 11g.

  As shown in FIG. 7, the data link allocation table can set two areas 1 and 2. In this embodiment, the number of areas that can be set is two following the previous area, but may be three or more. The area type, start address, and link data information are registered for each area. The area type is a type of a memory area in the IO memory 11f, such as a contact area (contact area) or a data memory area (data area). The start address stores the head address for registering data to be linked in the area. Further, the link data information stores a node to be data-linked (both own node and other nodes) and a storage capacity (number of channels) for storing data of the node. Then, the data of each node that is data-linked in order from the start address is stored in the order of the nodes registered in the link data information. That is, since the data link area to be registered as one area is contiguous and the data area to be registered for one node is also continuous, the data of each node is determined by the start address and link data information. Is uniquely determined.

  For example, taking the network system shown in FIG. 5 as an example, the node number of PLC (A) is 1, the node number of PLC (B) is 2, the node number of PLC (C) is 3, and the three PLCs are mutually connected. Data link shall be performed. In this case, assuming that 100 areas are allocated from 100 addresses of the data memory area of PLC (A) as the data link area of area 1, the area type of area 1 shown in FIG. Area "and the start address is 100. The link data information is as illustrated.

  By referring to the data link allocation table, the CPU unit 11 and the communication unit 12 use which memory area of the IO memory as a data link area, and each node has its own node area to be shared with data and other nodes. While recognizing the area, data sent from other nodes can be stored in a corresponding predetermined memory area. That is, since the PLC (A) knows that its own node address is “1”, from the area type and the start address, No. 100 to No. 199 in the data memory area store its own node data. It recognizes that it is an area, and recognizes that the area from No. 200 to No. 299 is another node area for storing data sent from the PLC (B) as the node 2, and No. 300 to No. 399. Can be recognized as an area of another node that stores data transmitted from the PLC (C) that is the node 3. The function of performing this data link is the same as that conventionally known.

  Briefly, in the present embodiment, the data link allocation table is stored in the data storage nonvolatile memory 11g of the CPU unit 11, so that when the power is turned on, the communication unit 12 (MPU 12a) The data link allocation table stored in the data storage nonvolatile memory 11g is read. Actually, the ASIC 11e issues a read request, and the ASIC 11e reads the data link allocation table and passes it to the MPU 12a. The MPU 12a checks the logic of the setting contents of the acquired data link allocation table, and if there is no problem, expands and uses the data link allocation table in the work RAM 12c in the communication unit 12.

  After completing the above initial processing, a normal data link is started. That is, the MPU 12a of each communication unit 12 obtains the transmission area of its own node according to the data link allocation table stored in the work RAM 12c (for example, addresses 100 to 199 in the data memory area in the PLC (A)). Next, the MPU 12 a of the communication unit 12 reads the data of the area from the IO memory 11 f of the CPU unit 11. In practice, a read request is issued to the ASIC 11e of the CPU unit 11, the ASIC 11e accesses the IO memory 11f, reads predetermined data, and passes it to the MPU 12a. Then, the MPU 12a of the communication unit 12 transmits the own node transmission data read from the CPU unit 11 to the network 20 by simultaneous broadcast communication.

  On the other hand, if each node (for example, PLC (B), (C)) in the network 20 receives the broadcast data link data, it confirms the node address of the transmission source and sets it as its own node. In accordance with the data link allocation table, whether or not to write the data of the node to the CPU unit and the area type and address of the write destination are determined. In this case, it is determined whether or not the node address “1” of the PLC (A) is registered in the link data information of the respective data link allocation table. If registered, the storage destination area of the node 1 is registered. The top address of is calculated. This head address can be obtained from the start address of area 1 and the data area of each node registered in the link data information. For example, in the example shown in FIG. 7, the start address of node 1 in area 1 is the start address, the start address of node 2 is start address +100, and the start address of node 3 is start address +200.

  Then, the MPU 12a of the communication unit 12 issues a write request to the CPU unit 11 when the received data is data reflected in the CPU unit 11, that is, data to be data-linked. In response to this, the CPU unit 11 (ASIC 11e) writes the received data in a designated area (address) of the IO memory 11f in accordance with a request from the communication unit 12. Thereby, the data stored in the local node area of the data link area can be transmitted to another node, and the data of the other node can be registered in the area of the corresponding other node of the data link area.

  In the example shown in FIG. 5, the number of areas set in each node for area 1 is 100. However, it is of course possible to take different values, and the start address for area 1 in each PLC is different. There is no problem. Furthermore, as shown in Patent Document 2, the memory areas allocated to the same node may be different. That is, “100” data may be sent from the transmission side, and some data may be formally acquired and stored in its own predetermined data area on the reception side.

  The data link allocation table is set by the support tool (PC). When the user sets the data link allocation table, in the above-described embodiment, it is stored in the data storage nonvolatile memory 11g of the CPU unit 11, but may be stored in the nonvolatile memory on the communication unit 12 side. Good.

  Here, in the present invention, as shown in FIG. 5, a plurality of data memory areas (areas 1 and 2) can be registered in the same area type (data memory area in the illustrated example). That is, conventionally, when the data link of area 1 is set in the data memory area, the data link of area 2 is set to, for example, the contact area other than the data memory area. A plurality of data link areas can be set to the same area type. That is, for example, in the case of the data link allocation table in PLC (A), the area type of area 1 in FIG. 7 is the data memory area and the start address is 100, but the area type of area 2 is also data. It becomes a memory area. The start address of area 2 is 500, and the link data information is as shown.

  In the data link allocation table shown in this way, it is allowed to register the same type in area 1 and area 2 as the area type. However, even in this case, the data link area is a continuous area area for each area. Since the setting of multiple data link areas within the same area type is permitted in this way, the support tool needs a function to check that the data link areas set in multiple areas do not overlap. It becomes.

  According to the present embodiment, by allocating a plurality of data link areas to a single area (for example, DM (data memory) area), the user can select one area (in which data is exchanged with other nodes on the network). Centralized management in one area). As a result, it becomes easy to avoid erroneous writing or reading of data.

  Conventionally, paying attention to the type of data to be data-linked, the input / output contact information stored in the contact area (area) and the various information stored in the data memory area (area) are respectively displayed in area 1 and area 2. The data link was performed for each area type. In contrast, in this embodiment, for example, a data link is performed using a single area such as one data memory area, but the input / output contact information stored in the contact area as in the prior art is used. When data linking (data sharing) is performed, the contact information stored at a predetermined address in the contact area is copied to a predetermined area of the own node area to be data-linked or stored in another node area by using a copy function between memories. This can be done by copying the input / output contact information to its own contact area. In this case, for example, area 1 shown in FIG. 5 can be used as a data link area for data to be stored in the original data memory, and area 2 can be used as a data link area for contact information. Of course, data link may be performed in the area 1 in a state where a plurality of bytes of data to be stored in the original data memory and 1-bit contact information are mixed.

  Further, according to the present embodiment, there is a system that initially performs data link using only area 1 as shown in FIG. 8 (a), and a request to increase the data link area for system expansion is required. Can be dealt with by newly allocating the increase in the data link area as area 2 as shown in FIG. In this way, since the original data link area allocation (area 1) remains unchanged from the beginning, the data link area can be increased without changing the ladder program of the existing part. Therefore, the system can be changed easily and easily, and the existing ladder program is not changed, so that the portion that has been operating normally can be secured.

It is a figure which shows a prior art example. It is a figure which shows a prior art example. It is a figure explaining the conventional problem. It is a figure explaining the conventional problem. It is a figure explaining one suitable embodiment of the present invention. 1 is a block diagram illustrating a preferred embodiment of the present invention. It is a figure which shows an example of a data link allocation table. It is a figure explaining an example of the effect of this invention.

Explanation of symbols

10 PLC
11 CPU unit 11a MPU
11b ROM
11c Work RAM
11d User memory 11e ASIC
11f IO memory 11g Non-volatile memory for data storage 11h Internal bus 12 Communication unit 12a MPU
12b ROM
12c Work memory 12d Communication interface 12e Internal bus 13 PLC interface 20 Network

Claims (3)

A data link function for sending and receiving shared data to be shared with other nodes connected to the network;
The node includes a plurality of types of memory areas including a contact area for storing contact information and a data memory area for storing information of a plurality of bytes.
A node characterized in that a plurality of data link areas for storing data to be shared can be set in the same memory area. A data link function for sending and receiving shared data to be shared with other nodes connected to the network;
The node includes a plurality of types of memory areas including a contact area for storing contact information and a data memory area for storing information of a plurality of bytes.
A node characterized in that another data link area can be additionally set in a memory area in which a data link area for storing data to be shared is already set. A data link allocation table for storing information for specifying a storage area of the data link area;
A node having a function of accessing a predetermined storage area of the memory area based on the data link allocation table and reading / writing data.

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