JP2001255909A - Method and device for communicating programmable controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the communication method of a PLC(programmable controller) for taking into consideration of dispensing with the conversion of a message format on a ladder program at connecting of the PLC or personal computers of plural makers. SOLUTION: This communication method of a PLC(programmable controller), having a general communication port is provided with a function 12 for transmitting a transmission message from ladder program sides 4 and 10 to an equipment 3 connected to a communication port, and for receiving data from the outside part through the communication port, a function 11 registered and connected by a user for generating a transmission message according to the equipment, and for converting the received message into inside data, and a function for allowing a user to prepare the conversion processing into the transmission message and the conversion processing of the reception message by selecting the registered message generating function. In this case, the converting functions are registered successively in a communicating module, so that communication with the equipment 3 whose message format is different can be performed by allowing the communicating module to have the converting functions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to communication and control between different kinds of devices such as programmable controllers having different message formats.

[0002]

2. Description of the Related Art Conventionally, when a programmable controller (hereinafter abbreviated as PLC) is connected to a device such as a personal computer by communication, or when PLCs of a plurality of manufacturers are connected by communication, the personal computer or the like conforms to the message format of the manufacturer. You can create a program on the personal computer side,
When PLCs of a plurality of manufacturers are connected by communication, the message format differs for each manufacturer, so it is necessary to match the message format of one company. In such a case, conventionally, a message format of another manufacturer is generated on a ladder program and communication is performed.

[0003]

However, in the above conventional example, since the format conversion is performed on the ladder program, there is a problem that not only the processing time of the ladder program becomes long but also the program itself becomes complicated. Was. Therefore, the present invention provides PLC
It is not necessary to consider the conversion of the message format in the ladder program when connecting the ladder program or when connecting a personal computer.By making the communication function to generate the message, the ladder program can be complicated and the processing time can be shortened. It is an object of the present invention to provide a programmable controller communication method and communication device that can be achieved.

[0004]

According to a first aspect of the present invention, there is provided a communication method for a programmable controller having a general-purpose communication port. A function to send a transmission message to a connected device, a function to receive data from the outside via a communication port, a function to generate a transmission message according to the device by registering and connecting to a user, and a function to receive a message By using a programmable controller having a function of converting a message to internal data, by selecting the registered message generation function and performing a conversion process to a transmission message and a conversion process of a reception message, it is suitable for a system constructed by a user. Communication configuration that can be easily configured That. According to a second aspect of the present invention, a communication device for a programmable controller having a general-purpose communication port transmits a transmission message from a ladder program to a device connected to the communication port, and A communication means for receiving data from a communication port via a communication port, a message format conversion means for generating a transmission message according to a device registered and connected by a user, and converting the received message into internal data; Message creation means for creating a conversion process between a transmission message and a reception message by selecting a means by a user. The invention described in claim 3 is:
The message format conversion means comprises an input / output portion which does not depend on the connection device and a message format conversion routine which depends on the connection device. The message format conversion routine assigns registration numbers to the communication device via the input device in the order of registration. It is characterized by shaking and registering, and allowing the user to select by the registration number according to the partner device. According to the communication method and the communication device of the programmable controller, a communication processing portion (for example, a communication module or the like) of the programmable controller is divided into functions, a message format conversion portion is blocked, and the message format conversion routine is requested by a user. , Or a user can directly create a program. A plurality of such conversion routines are incorporated in the communication function part, and by specifying which conversion routine to use from the ladder program according to the partner device, communication between different types of PCs or communication with personal computers by multiple manufacturers can be performed on the ladder program. This makes it possible without considering the conversion of the message format.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a programmable controller according to an embodiment of the present invention. FIG.
FIG. 2 is a functional block diagram of a communication device of the programmable controller shown in FIG. 1. FIG. 3 is an explanatory diagram of the message format conversion function shown in FIG. FIG. 4 is an explanatory diagram of a message creation function using the message format conversion function shown in FIG. In FIG. 1, reference numeral 1 denotes a PLC (programmable controller), which is, for example, a rack-mount type PLC in which various modules such as a power supply, a CPU, communication, and I / O are individually detachably mounted on a mount base. Reference numeral 2 denotes a PLC communication device (communication module) which communicates with a plurality of PLCs, personal computers, and the like by a half-duplex synchronization method or the like via a communication interface RS-232C. 3 is RS2 from the communication module 2
It is a PLC (heterogeneous PLC) made by another manufacturer or a personal computer that is connected by the 32C communication method and forms a network with the PLC 1. A CPU module 4 decodes a ladder program, performs a PLC scan process, and the like. Reference numeral 5 denotes a programming device, which is a device for personal computer-type programming input and monitoring.
Used when registering with the communication module 2 via the. Reference numeral 6 denotes a communication port of the communication module 2, which communicates with a plurality of different types of PLCs 3 constituting a network. Reference numeral 7 denotes a power supply module of the PLC 1 for supplying various power supplies. 8 is an I / O module. (Note that in the following description, the CPU module 4 and the communication module 2 will be described as functionally separate modules as shown in FIG.
Although the H.232C communication system is assumed, CP
The U module 4 and the communication module 2 may be integrated, and the communication method is also applicable to a communication method such as ETthernet). As shown in FIG. 2, the communication module 2 has a CP
Interface unit 10 with U module, message format converter 11, RS-232C communication controller 1
And 2. The message format converter 11 includes a different PLC connected by the user to the network.
The message format conversion routine 3 is registered from the programming device 5 via the CPU module 4 and the interface unit 10 each time. (Note that a message format conversion routine for a heterogeneous PLC 3 or the like whose connection model name is known from the beginning,
In some cases, it is registered by the LC manufacturer and shipped in a registered form.)

Next, the operation will be described with reference to the drawings. Now, as a simple example of communication of the present system, considering the reading of the internal coil of the connected heterogeneous PLC 3, the function of the communication module 2 in this case is divided as shown in FIG. In FIG. 2, the interface 10 with the CPU module 4 and the RS-232C communication control unit 12 can be used in common irrespective of the connected device, and can be connected to various types of devices such as PLCs. The part that needs to be converted is the part of the conversion routine of the message format conversion unit 11. In the example of reading the internal coil, if the command is issued to the message format converter 11 through the interface 10 of the CPU module, as shown in FIG. 3, the input is a command to read the internal coil and the number of data to be read (the number of data). )When,
It is the first three addresses. These are connected devices (different P
It can be performed using the same command even if the LC changes). Also, RS-2 after message format conversion
The command for the 32C communication control is a transmission command (or a transmission request), the number of transmission data, and the specification of a buffer of a message to be transmitted. This is also a part unrelated to the content of the message. Therefore, the input and output patterns of the message format converter 11 can be defined as shown in FIG. Also, the processing when data is received is only the reverse of the order, and the processing contents and data transfer between each function are exactly the same.

Next, a description will be given of a part of a message format conversion routine which differs for each type of PLC. In this case, two cases are conceivable: a case where a user creates a program by himself / herself to establish communication between different types of PLCs; and a case where a PLC maker side registers and ships in advance at the request of the user for a specific user. In any case, a message format conversion routine is developed while keeping the input / output format described in FIG. The message format conversion routine is, for example, one PLC
Command “Read Coil 1000 16” (read 16 coil data from address 1000)
However, on one of the heterogeneous PLCs, “Read (Coil, 10
In the case of "00, 16", differences in individual message formats are converted to convert and absorb differences between models. (It is considered that there are a plurality of message format conversion routines different for each connected device, and the message format conversion routine is not limited to a specific method.) The message format conversion routines developed in this manner are transmitted from the programming device 5 shown in FIG.
The information is sequentially registered in the communication module 2 via the module 4. In the communication module 2, registration numbers are assigned to various message format conversion routines in the order of registration. The number of conversion routines currently registered in the communication module 2 can be confirmed from the programming device 5. As described above, the present embodiment does not particularly consider individual conversion schemes, but a plurality of different PLs.
It is an object of the present invention to develop a conversion routine for C3 and to present a method for constructing a general-purpose system that facilitates communication with many different types of PLCs 3 by registering a user from the programming device 5 to the communication module 2.

FIG. 4 shows a communication module 2 in which various message format conversion routines have been registered.
FIG. 4 is a diagram for explaining a function of creating a transmission / reception message conversion process performed by a user in the case of actual communication using FIG.
1 shows a schematic diagram of a message creation function 20 composed of a communication module, a programming device as input means, a CPU module, and a network. The message creation function 20 has a control register A for coil reading, a reception buffer B for reception, and a communication command (COM) in response to input of a start command and a stop command from a user. FIG. 4B shows the contents of the coil readout control register A and the reception buffer B used for transmission and reception. The contents of the control register A are as follows: “used port, used routine (message format conversion routine),
Command, number of data, head address ", and the same reception content is stored in the reception buffer B at the time of reception. FIG. 4 shows a processing procedure of the message creation function as described above.
As shown in (a), the user selects the target message format conversion routine for the heterogeneous PLC 3 by the registration number, and activates the message creation function 20 according to the activation instruction. I,
The data converted by the selected message format conversion routine is transmitted to the RS-23 by the transmission command COM.
The data is transmitted from the 2C communication control unit to the target heterogeneous PLC 3.
As described above, according to the present embodiment, the communication function in the PLC is divided, and the user or the like can develop only the conversion processing part depending on the connected device (heterogeneous PLC or the like).
The conversion routine for the number of connected devices added to the system allows the user to sequentially incorporate the functions into the communication function each time, so that even after the PLC has been put into the system after leaving the maker's stage, communication according to the connected devices can be performed. The system can be easily constructed. In addition, by giving the message generation to the communication function in this way, it is not necessary to consider the message format in the ladder program, and the efficiency of the communication system is improved. In the description so far, a separate module configuration has been described for each function of the communication module that performs communication with the CPU module that executes the decoding of the ladder program. However, the present invention is similarly applicable to a system in which this is integrated in mounting. It goes without saying that it applies. As an example of the communication mode, RS-2
Although the description has been made assuming 32C communication, it is of course applicable to communication forms such as Ethernet (registered trademark) using the N-to-N token passing method.

[0009]

As described above, according to the present invention,
The communication processing part of the programmable controller with a general-purpose communication port is divided into functions, the message format conversion part is blocked, and the message format conversion routine is created by the manufacturer at the request of the user, or
Alternatively, a plurality of these message format conversion routines are incorporated in the communication function part so that the user can directly create a program, and a ladder program specifies which message format conversion routine to use, thereby enabling communication between a plurality of PLCs and PCs manufactured by a plurality of manufacturers. The communication is easily performed, so that connection with a connection device such as a PLC or a personal computer of another manufacturer can be easily performed, and in that case, the ladder program can be simplified and the processing time can be shortened.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a programmable controller according to an embodiment of the present invention.

FIG. 2 is a functional block diagram of a communication device of the programmable controller shown in FIG.

FIG. 3 is an explanatory diagram of a message format conversion function shown in FIG. 2;

4 is an explanatory diagram of a message creation function using the message format conversion function shown in FIG.

[Explanation of symbols]

1 Programmable controller 2 Communication module 3 Programmable controller made by another manufacturer
C) 4 CPU module 5 Programming device 6 Communication port 7 Power supply module 8 I / O module 10 Interface unit 11 Message format conversion unit 12 RS-232C communication control unit 20 Message creation function

Claims (3)

[Claims] 1. A communication method for a programmable controller having a general-purpose communication port, comprising: a function of sending a transmission message from a ladder program to a device connected to the communication port; and receiving data from the outside via the communication port. Using a programmable controller that has a function to generate a transmission message according to the device registered and connected by the user and a function to convert the received message to internal data, and select the registered message generation function A communication method for a programmable controller, wherein a communication mode suitable for a system constructed by a user is configured by performing a conversion process into a transmission message and a conversion process into a reception message. 2. A communication device for a programmable controller having a general-purpose communication port, wherein a transmission message is transmitted from a ladder program to a device connected to the communication port, and data is received from the outside via the communication port. Means and user registration /
Message format conversion means for generating a transmission message according to the connected device and converting the received message into internal data, and message creation for selecting a message format conversion means by a user to generate a conversion process of the transmission message and the reception message And a communication device of a programmable controller. 3. The message format conversion means comprises an input / output part which does not depend on a connection device and a message format conversion routine which depends on a connection device.
3. The message format conversion routine according to claim 2, wherein a registration number is assigned to the communication apparatus via the input means in the order of registration and registered, and the user can select the registration number according to the partner device. Communication device for programmable controller.