JP2008257400A - Programmable controller and unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a programmable controller for easily setting an IP address to a device (a node device) constituting other node such as an I/O device or a PLC. <P>SOLUTION: In this programmable controller, a CPU unit 11 is installed with a memory card 15 storing a DHCP (Dynamic Host Configuration Protocol)/BOOTP (Bootstrap Protocol) table wherein a MAC address of the device based on the industrial Ethernet standard and the IP address set to the device are associated. An IE communication unit 12 periodically sends requests to read the table to the CPU unit, and stores it into its own nonvolatile memory. When receiving a request to allocate the IP address from the node devices 20, 30, 40 each having a DHCP/BOOTP client function connected to an IE network 1, the nonvolatile memory is accessed, the IP address corresponding to the MAC address of the device having made the request is read, and the IP address is automatically set by returning the read IP address to the device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a programmable controller and a unit connected to an FA network that performs communication using an IP address.

  In a network system in FA (Factory Automation), one or a plurality of PLCs (programmable controllers) that control production facilities and devices whose operations are controlled by the PLCs are connected to a control system network. These PLCs and devices communicate with each other cyclically via the network of the control system, thereby transmitting / receiving IO data and controlling production facilities.

  The PLC connects a CPU unit that executes calculations based on a control program, an input device such as a sensor or a switch and inputs an on / off signal as an input signal, and an output device such as an actuator or a relay. Output units that send output signals to them, communication units that send and receive data to and from other devices connected to the network, master units for master-slave communication, power supply units that supply power to each unit, etc. It is configured by combining a plurality of units.

  Industrial Ethernet (registered trademark) is one of networks connecting one or more PLCs and I / O devices. A device connected to this network needs to support industrial Ethernet standards represented by EtherNet / IP and PROFINET. That is, since a device compliant with the standard performs manual communication using an IP address, it is necessary to set an IP address for a device connected to the network prior to the start of use. The IP address is set by preparing a dedicated configuration tool device and connecting the tool device to the device.

  As described above, when an IP address is set using a dedicated configuration tool device, it is necessary to perform a process for each device to be set, which is very complicated for the user. In addition, since there is not a common configuration tool device for all devices that support Industrial Ethernet (registered trademark), the operability of the configuration tool device may differ for each device (at least for each manufacturer). In that respect, it is not convenient for the user.

  It is also conceivable that a predetermined number of mechanical switches such as dip switches and rotary switches are installed in each device, and the IP address is directly set to the device by operating the mechanical switch. However, in order to set an IP address, eight mechanical switches are required, which increases the cost, and in the case of an I / O device that constitutes an FA network, eight pieces are required due to the physical size of the device. It becomes difficult to implement a mechanical switch.

  An object of this invention is to provide the programmable controller and unit which can set an IP address easily with respect to the apparatus (node apparatus) which comprises I / O apparatus, PLC, and other nodes.

  In order to achieve the above-described object, in the programmable controller of the present invention, (1) a table for storing a table in which a MAC address of a device compliant with the industrial Ethernet (registered trademark) standard and an IP address set for the device are associated with each other. A storage unit and a DHCP / BOOTP server for assigning an IP address to a device connected to the network, and the DHCP / BOOTP server sends an IP address assignment request together with the MAC address of the device from the device connected to the network. When receiving, the table storage means is accessed, the IP address corresponding to the acquired MAC address is read, and the read IP address is returned to the device.

  In this way, a device to which no IP address is assigned transmits an assignment request in a state where it is connected to the network, whereby an IP address is automatically returned from a programmable controller having a DHCP / BOOTP server function. Therefore, communication can be performed based on that. Therefore, the user does not need to set an IP address for each device, and can easily set an IP address.

  The programmable controller includes both a type configured by connecting a plurality of units and an integrated type in which necessary functions are mounted. The table data stored in the table storage means is created separately by the user and stored by various methods. The means for storing can be downloaded directly to the programmable controller using, for example, a configuration tool device, or (2) the table is stored in an external auxiliary storage medium that can be attached to the programmable controller, and the external auxiliary storage medium The table read from can be stored in the table storage means. In the embodiment, the external auxiliary storage medium corresponds to a memory card attached to the CPU unit. By using the memory card, the user can easily register / update the table. The table stored in the external auxiliary storage medium may be read periodically or at a predetermined timing and stored in the table storage means.

  (3) The IP addresses stored in the table may be allowed to allow duplicate registration of the same IP address for different devices to be exchanged. In this way, when a certain device fails and is replaced, the same IP address is returned in response to an IP allocation request from the replaced device by keeping the same IP address for the replaced device. . Therefore, other devices and programmable controllers can perform communication processing with respect to the replaced device without any particular change processing during the replacement processing.

  (4) The table associates the device name to be set to the device in addition to the MAC address and the IP address, and the user program executed by the programmable controller is described using the device name as information for identifying the communication partner device. Then, when actually communicating with the device, it is preferable to obtain an IP address by referring to the table and perform communication using the obtained IP address. In this way, a user program can be created without knowing the IP address of the communication partner, and convenience is improved.

  (5) The unit of the present invention includes a table storage means for storing a table in which a MAC address of a device compliant with the industrial Ethernet standard and an IP address set for the device are associated, and an IP address for a device connected to the network. A DHCP / BOOTP server that, when receiving an IP address assignment request together with the MAC address of the device from a device connected to the network, accesses the table storage means; An IP address corresponding to the acquired MAC address is read out, and a function of returning the read IP address to the device is provided. In the embodiment, it is realized by the IE communication unit, but may be realized by another unit such as a CPU unit.

  According to the present invention, an IP address can be easily set for an I / O device, a PLC, and other devices (node devices) constituting a node.

  FIG. 1 shows an example of an FA network system to which the present invention is applied. PLC 10 or PT (program display) having a DHCP (Dynamic Host Configuration Protocol) (or BOOTP (Bootstrap Protocol)) server function for setting an IP address in an industrial Ethernet (hereinafter abbreviated as “IE”) network 1 Connect one or more units. The IE network 1 is connected to node equipment corresponding to the IE. Examples of the node device include a PLC 20 having a DHCP (or BOOTP) client function, an I / O terminal 30 having a DHCP (or BOOTP) client function, and an I / O device 40 having a DHCP (or BOOTP) client function. .

  The PLC 10 is a building block type and includes a CPU unit 11, an IE communication unit 12, and other units 13. Similarly, the PLC 20 is a building block type, and includes a CPU unit 21, an IE communication unit 22, and other units 23. The IE communication unit 12 is provided with a DHCP (or BOOTP) server function, and the IE communication unit 22 is provided with a DHCP (or BOOTP) client function. Both of these functions are realized by firmware. The other units 11 and 22 are various units for realizing the functions of the PLC. In the figure, only one is drawn for convenience, but the number of settings is arbitrary, and can be increased or decreased as necessary. The

  The I / O terminal 30 includes an I / O terminal 32 that connects an input / output device 31 such as a sensor or a relay, and a communication coupler 33 that is connected to the IE network 1 and communicates with other node devices. The communication coupler 33 is provided with a DHCP (or BOOTP) client function.

  The I / O device 40 connected to the IE network 1 is also called a high function (intelligent) I / O or the like, and is an input device (device) or an output device (device) having a communication function. Examples include a barcode reader, a motion controller, an image processing device, and a sensor. The I / O device 40 includes a communication adapter 41 in which a DHCP (or BOOTP) client function is implemented.

  Next, the IP address automatic setting function will be described. First, a DHCP / BOOTP table is stored in a memory card 15 that is an external auxiliary storage medium mounted on the CPU unit 11 of the PLC 10. This DHCP / BOOTP table is a table in which a MAC address uniquely set for each device / device is associated with an IP address assigned to the device having the MAC address. Specifically, the table structure is as shown in FIG. 2, and in this embodiment, the device name and the net mask are further associated with each other.

  Each data constituting this table is created in advance by a user using various tool devices and registered in the memory card 15. The user acquires the MAC address of each device that constructs the FA network created by the user, associates the acquired MAC address with the IP address, and is a name for facilitating human identification (recognition) of the device. The device name is arbitrarily determined. The DHCP / BOOTP table registered in the memory card 15 can be accessed and read from the CPU unit.

  FIG. 3 shows the internal structure of the IE communication unit 12. The IE communication unit 12 is connected to the IE network 1 and includes a value communication controller 12a, a nonvolatile memory 12b, an MPU 12c, a ROM 12d, a RAM 12e, and a backplane bus 12f, which are mutually connected by an internal bus 12g. Is communicably connected.

  The ROM 12d is written with TCP / IP and UDP / IP, which are Ethernet (registered trademark) standard protocols, and also a DHCP / BOOTP server operating on this protocol stack. The RAM 12e is a work area necessary for these protocols to operate. The MPU 12c reads various programs stored in the ROM 12d, uses the RAM 12e as a work memory, and executes predetermined processing. In terms of the relationship with this embodiment, the MPU 12c executes an IP address setting process. Further, the non-volatile memory 12b stores a DHCP / BOOTP table read from the CPU unit 11 via a pack plane bus by a dedicated command. Note that the DHCP / BOOTP table stored in the nonvolatile memory 11b can be directly written into the nonvolatile memory 12b by the configuration tool device.

  The hardware structure of the IE communication unit 22 is the same as that shown in FIG. However, the ROM is different from the IE communication unit 12 in that TCP / IP and UDP / IP and a DHCP / BOOTP client operating on the protocol stack are written in the ROM.

  FIG. 4 shows a processing procedure for automatic IP address setting, and FIGS. 5 and 6 are flowcharts showing functions for setting an IP address in the IE communication unit 12 and the IO device. First, as shown in FIG. 4, the IE communication unit 12 of the PLC 10 and the CPU unit 11 are connected by a backplane bus 16. That is, the backplane bus 16 is an internal bus that connects the IE communication unit 12 and the CPU unit 11, and can exchange data bidirectionally by a dedicated command. For example, reading out data in a memory card mounted in the CPU unit 11 also uses a dedicated command. The actual IP address setting procedure is as follows (1) to (4).

  (1) The IE communication unit 12 having the DHCP / BOOTP server function requests the CPU unit 11 in advance (or periodically) to read out the DHCP / BOOTP table in the memory card 15 with a dedicated command.

  (2) The CPU unit 11 interprets the dedicated command, reads the DHCP / BOOTP table in the memory card 15, and sends it back to the IE communication unit 12 via the backplane bus 16. Upon receiving this reply, the IE communication unit 12 stores the acquired DHCP / BOOTP table in the nonvolatile memory 12b. The processes (1) and (2) are performed by executing process step S1.

  (3) A node device (PLC, 20, I / O terminal 30, I / O device 40) having a client function of the DHCP / BOOTP protocol, together with its own MAC address, when an IP address is not set in itself. A request for IP address assignment is made to the DHCP / BOOTP server. That is, a DISCOVER frame is transmitted. The DISCOVER frame includes the source MAC address. Such processing is performed by the node device executing the processing steps S11 and S12 of FIG.

  (4) The IE communication unit waits to receive an IP address allocation request (DISCOVER frame) (S2). If received, the IE communication unit refers to the previously read DHCP / BOOTP table and determines the IP address corresponding to the MAC address. Read (S3). Then, the OFFER frame is returned to the requested node device according to the DHCP / BOOTP protocol (S4). The node device waits to acquire its own IP address (S13), and if an IP address is returned by the OFFER frame from the IE communication unit 12 having the DHCP / BOOTP server function, acquires it (S13). Yes), the process ends. In practice, the node device recognizes the returned OFFER frame as its own IP address, and transmits the REQUEST frame again. Thereafter, if a PACK is returned from the DHCP server, it is set as its own IP address (a value is stored in the internal memory).

  Further, the IE communication unit 22 (which implements the DHCP (or BOOTP) client function) that does not have a DHCP / BOOTP table acquires its own IP address from the IE communication unit 12 according to the above-described procedure, and further, the IE communication unit 12 A DHCP / BOOTP table is downloaded from, and the table is stored in its own nonvolatile memory.

  That is, as shown in FIG. 8, processing steps S11 to S13 are executed to have the IE communication unit 12 set its own IP address. Next, the IE communication unit 22 determines whether or not it has a DHCP / BOOTP table (S14), and if it does not have a table, sends a DHCP / BOOTP table read command to the DHCP / BOOTP server. Issued, the DHCP / BOOTP table is read and stored in the internal memory (non-volatile memory) (S15).

  After an IP address is set for each device connected to the IE network 1 as described above, communication is performed using the IP address. In the present embodiment, the IP address of the partner node specified when performing message communication can be specified from the user program in the CPU unit using the device name in the DHCP / BOOTP table. That is, for example, when a message transmission user program (ladder diagram) as shown in FIG. 8A is described, the IP address of the destination partner node is stored in the DM01000 memory area, and the DM02000 memory area is stored in the DM02000 memory area. Stores transmission data. However, in this embodiment, as shown in FIG. 8B, DM01000 stores “Machine 5” as the transmission destination address. Then, as shown in FIG. 8C, the actual transmission data is stored in DM02000.

  When the message transmission command in the user program is executed, the CPU unit passes data (communication parameters such as a transmission destination address, transmission data, etc.) of this command to the IE communication unit by a dedicated command (see FIG. 9). . Then, since the device name is described as the transmission destination address in the transmission destination parameter in the data passed to the IE communication unit through the backplane bus, the IE communication unit refers to the DHCP / BOOTP table. The destination IP address associated with the device name is read out. Then, the IE communication unit transmits a message using the IP address according to a procedure of creating a communication message using the read IP address and sending it to the IE network.

  According to the above, in the CPU unit, since the device name is embedded in the dedicated command as it is and the device name is passed to the IE communication unit, the CPU unit does not need to resolve the transmission destination IP address. Since the destination IP address is resolved with reference to the DHCP / BOOTP table in the IE communication unit, when the destination IP address is changed, only the DHCP / BOOTP table needs to be changed. For this reason, it is not necessary to change the user program itself in the CPU unit.

  On the other hand, when a message is received, the device name of the transmission source node is passed to the CPU unit by executing the reverse of this processing flow. That is, assume that a user program as shown in FIG. 10 is described. Then, the IE communication unit extracts the transmission source IP address from the received communication message. Then, the IE communication unit refers to the DHCP / BOOTP table and reads the device name from the transmission source IP address. The device name is set in the transmission source parameter as the transmission source address, and the received message (communication parameters such as the transmission source address, reception data, etc.) is sent to the CPU unit by a dedicated command (see FIG. 11) via the backplane bus. give. Then, when the CPU unit executes the reception command in the user program, it writes the device name as the transmission source address in the area (DM03000) specified by this command (see FIG. 11 (a)) and also in the area (DM04000). Received data is inserted) (see FIG. 11B).

  Therefore, the user does not need to know the IP address of the counterpart node, and even if the IP address of the counterpart node is changed, it is only necessary to change the DHCP / BOOTP table, and the user program itself does not need to be changed. .

  On the other hand, in the present embodiment, registration of duplicate device names and duplicate IP addresses is permitted in the DHCP / BOOTP table. In other words, if a specific I / O device needs to be replaced due to a cause such as a failure, it is possible to register the MAC address, device name, and IP address association for the replacement device in this table in advance. It becomes possible. For example, as shown in FIG. 13, when the device name “Device_123” is registered twice, the device having the MAC address of 12345789 ACF was initially used, but it was replaced with the device having the MAC address of 1234578989 AD0. In this case, the same IP address can be assigned to the replaced device. Since the IP address does not change with the replacement of the device, other devices connected to the IE network can cope with the user program without changing them.

It is a figure which shows an example of a network structure. It is a figure which shows an example of a DHCP / BOOTP table. It is a figure which shows the internal structure of IE communication unit. It is a figure explaining the allocation processing function of an IP address. It is a figure explaining the allocation processing function of the server side IP address. It is a figure explaining the assignment processing function of the IP address on the client side. It is a figure explaining the function of IE communication unit by the side of a client. It is a figure explaining the effect | action of a message transmission process. It is a figure which shows the data structure of the exclusive command of message transmission. It is a figure explaining the effect | action of a message reception process. It is a figure which shows the data structure of the command for exclusive use of message reception. It is a figure explaining the effect | action of a message reception process. It is a figure which shows an example of a DHCP / BOOTP table.

Explanation of symbols

10 PLC (with DHCP / BOOTP server function)
11 CPU unit 12 IE communication unit 12a communication controller 12b nonvolatile memory (table storage means)
12c MPU
12d ROM
12e RAM
12f Backplane bus I / F
12g Internal bus 13 Other unit 15 Memory card 16 Backplane bus 20 PLC (with DHCP / BOOTP client function)
21 CPU unit 22 IE communication unit 23 Other unit 30 I / O terminal 40 I / O device

Claims (5)

Table storage means for storing a table in which a MAC address of a device compliant with the industrial Ethernet standard and an IP address set for the device are associated with each other;
A DHCP / BOOTP server that assigns IP addresses to devices connected to the network
When the DHCP / BOOTP server receives an IP address assignment request together with the MAC address of the device from the device connected to the network, the DHCP / BOOTP server accesses the table storage unit and reads the IP address corresponding to the acquired MAC address. A programmable controller comprising a function of returning the read IP address to the device.   The programmable table according to claim 1, wherein the table is stored in an external auxiliary storage medium that can be attached to a programmable controller, and the table read from the external auxiliary storage medium is stored in the table storage means. controller.   The programmable controller according to claim 1 or 2, wherein the IP address stored in the table allows the same IP address to be registered repeatedly for different devices to be exchanged. In addition to the MAC address and the IP address, the table associates a device name set to the device,
The user program executed by the programmable controller is described using the device name as information for specifying the communication partner device,
4. When actually communicating with a device, an IP address is acquired by referring to the table, and communication is performed using the acquired IP address. Programmable controller given in the paragraph. Table storage means for storing a table in which a MAC address of a device compliant with the industrial Ethernet standard and an IP address set for the device are associated with each other;
A DHCP / BOOTP server that assigns IP addresses to devices connected to the network
When the DHCP / BOOTP server receives an IP address assignment request together with the MAC address of the device from the device connected to the network, the DHCP / BOOTP server accesses the table storage unit and reads the IP address corresponding to the acquired MAC address. A programmable controller unit comprising a function of returning the read IP address to the device.

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