CN114338274A - Heterogeneous industrial field bus fusion method and system - Google Patents

Abstract

The invention discloses a heterogeneous industrial field bus fusion method and system, which solves the disadvantages of heterogeneity and poor software maintenance and reliability caused by the coexistence of field bus standards. , build a master/slave control network, based on the Modbus RTU message model and CANopen message model, with the support of the data structure and processing functions provided by the set RTOS, obtain parameters, and build Modbus RTU and CANopen message frames based on the queuing network model The packaging and unpacking mechanism of the invention abstracts the management of interactive tasks and the management of buffers into a mode of multi-task, multi-queue and multi-service when data is continuously exchanged between two protocols. A heterogeneous industrial field bus fusion method of the present invention And the system can make the devices connected to various industrial fieldbuses easily integrated into the IT network, and realize the intercommunication and integration of industrial fieldbus networks.

Description

A kind of heterogeneous industrial field bus fusion method and system

technical field

The invention relates to an industrial field bus technology, in particular to a method and system for integrating heterogeneous industrial field buses.

Background technique

At present, there are more than a dozen fieldbus technologies widely used in the industrial Internet of Things market, which effectively solve the communication and control command transmission problems between industrial instruments, controllers, actuators, and electromechanical equipment. However, the heterogeneity caused by the coexistence of various types of fieldbus standards has brought trouble to communication procedures, user selection, and hardware implementation. At the same time, the system software support corresponding to the fieldbus is even more flourishing, and there is no unified open design. It is difficult to reflect the reusability of software, which increases the cycle of software development, and its maintainability and reliability are also poor.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a heterogeneous industrial field bus fusion method and system, which can enable the devices connected to various industrial field buses to be easily integrated into the IT network, and realize the intercommunication and integration of industrial field bus networks.

The above-mentioned technical purpose of the present invention is achieved through the following technical solutions:

A heterogeneous industrial field bus fusion method, comprising the following steps:

S1. Build the basic environment for Modbus RTU and CANopen protocol implementation based on the set RTOS;

S2. For heterogeneous industrial fieldbus protocols, extract the commonality of implementation principles and abstract them into a fieldbus adapter model;

S3. Build a master/slave control network, which is a Modbus-type control network and a CANopen-type control network;

S4. Based on the Modbus RTU message model and the CANopen message model, with the support of the data structure and processing functions provided by the set RTOS, the master and slave station addresses, identification IDs, source node numbers, destination node numbers, and data domain parameters are obtained by categories. ;

S5. Based on the queuing network model, build a packaging and unpacking mechanism for Modbus RTU and CANopen information frames. When a certain industrial application scenario is to continuously exchange data between the two protocols, the management of interactive tasks and buffer management are abstracted into multiple Task multi-queue multi-service mode.

A heterogeneous industrial field bus fusion system, comprising a Modbus control network support module, a CANopen control network support module, and a gateway support module integrating the field bus;

The Modbus control network support module includes:

The baud rate configuration unit that configures the baud rate of Modbus master-slave communication,

The transfer mode configuration unit to configure the protocols supported by Modbus,

Set the query-response mechanism of master/slave communication of Modbus master and slave communication for "broadcast communication" and "point-to-point communication" respectively,

The slave station message pool used to save the messages sent by each slave station on the Modbus control network to the master station,

Gateway message pool for receiving information from other fieldbuses forwarded by the gateway,

The hardware driver of RS-485 supported by the interconnection between the signal receiver and the transmitter is realized through the underlying protocol RS-485 of Modbus RTU;

The CANopen control network support module includes:

The baud rate configuration unit that configures the baud rate of CANopen master-slave communication differently according to the communication distance,

Study the process data objects, service data objects, predefined objects, and network management objects described by the CANopen protocol.

Study the request-instruction-response-confirmation steps of the CANopen protocol master-slave communication and the request-instruction-response-confirmation mechanism of the control process,

Slave message pool for saving messages sent by each slave on the CANopen control network to the master,

Gateway message pool for receiving other fieldbus messages forwarded by the gateway

CAN hardware driver;

The gateway support module of the fusion field bus includes:

The Modbus protocol unpacking mechanism that parses the complete Modbus RTU message frame,

Modbus data domain pool,

The Modbus protocol packaging mechanism that encapsulates a certain data field information of the Modbus data field pool to be transmitted into a complete Modbus message frame,

CANopen protocol unpacking mechanism, CANopen data domain pool,

The CANopen protocol packaging mechanism that encapsulates a certain data domain information of the CANopen data domain pool to be transmitted into a complete CANopen message frame,

The Ethernet interface that encapsulates the data domain information of the two fieldbuses into an Ethernet message frame,

Hardware-driven RS-485 hardware driver and CAN hardware driver.

To sum up, the present invention has the following beneficial effects:

Through the constructed Modbus control network support module and CANopen control network support module, and in cooperation with the gateway support module of the integrated fieldbus to parse, unpack and pack the message frame, the devices connected to various industrial fieldbuses can be easily integrated. To the IT network, it realizes the integration of the OT network into the IT network, solves the problem of the integration of industrial heterogeneous networks, and has good market prospects and application value.

Description of drawings

Fig. 1 is the system design schematic diagram of the industrial field bus intercommunication;

Fig. 2 is the abstract schematic diagram of the hardware architecture of industrial field bus fusion;

Figure 3 is a technical roadmap for industrial fieldbus fusion.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings.

According to one or more embodiments, a heterogeneous industrial field bus fusion system is disclosed, which selects CANopen and Modbus RTU, two industrial field buses with high market share and wide application range, as shown in FIG. 1 , including a Modbus control network Support module, CANopen control network support module, gateway support module integrated with fieldbus.

Taking CANopen and Modbus RTU as an example, the industrial field bus intercommunication system is shown in Figure 1 and Figure 2, including:

Modbus controls network support module, which includes baud rate configuration, transmission mode configuration, query-response mechanism of master/slave communication, slave site message pool, gateway message pool and RS-485 hardware driver.

CANopen control network support module, which includes baud rate configuration, CAN communication object, request-instruction-response-confirmation mechanism, slave station message pool, gateway message pool and CAN hardware driver.

Gateway support module integrating fieldbus, including Modbus protocol packing mechanism, Modbus protocol unpacking mechanism, Modbus data domain pool, CANopen protocol packing mechanism, CANopen protocol unpacking mechanism, CANopen data domain pool, Ethernet interface, RS-485 hardware The driver, CAN hardware driver and modules supporting other functions of the gateway are the core modules to realize the intercommunication and integration of Modbus RTU and CANopen.

Further, in the Modbus control network support module:

The baud rate configuration is to configure the baud rate of the Modbus master-slave communication, and the transmission mode configuration is to configure the "RTU" and "ASCII" supported by Modbus.

Query-response mechanism of master/slave communication The query-response mechanism of Modbus master station and slave station communication is designed for "broadcast communication" and "point-to-point communication", that is, to ensure that function codes, error codes, check codes, etc. can be correct transmission during the cycle.

The slave station message pool is used to save the messages sent by each slave station on the Modbus control network to the master station, and the gateway message pool is used to receive the information of other fieldbuses forwarded by the gateway.

The hardware driver of RS-485 is RS-485, the underlying protocol of Modbus RTU, which realizes the interconnection support of signal receiver and transmitter, and designs RS-485 control logic from the perspective of hardware driver.

Further, in the CANopen control network support module:

The baud rate configuration is that the user can configure the baud rate of CANopen master-slave communication differently according to the communication distance, which reflects the corresponding relationship between the gradually increasing communication distance and the decreasing bit rate.

CAN communication object is to study the process data object, service data object, predefined object, network management object's data structure characteristics and operation mechanism described by CANopen protocol.

The request-instruction-response-confirmation mechanism is to study the steps and control flow of the request-instruction-response-confirmation of the CANopen protocol master-slave communication.

The slave station message pool is used to save the messages sent by each slave station on the CANopen control network to the master station, and the gateway message pool is used to receive the information of other fieldbuses forwarded by the gateway.

The CAN hardware driver is the hardware driver for the CAN control bus, the underlying bus of the CANopen protocol.

Further, in the support module of the industrial fieldbus fusion gateway:

The Modbus protocol unpacking mechanism parses out the "start bit", "device address", "function code", "data field", "CRC check digit" and "terminator" of the complete Modbus RTU message frame, respectively. The most critical "data field" information plus other key information form the "Modbus data field pool", and the Modbus protocol packaging mechanism encapsulates a "data field" of the "Modbus data field pool" to be transmitted into a complete Modbus message frame.

The CANopen protocol unpacking mechanism converts the complete CANopen message frame "sign", "source node number", "destination node number", "reserved", "number of bytes in the data field of the message frame", "the first data field" Byte" and "Nth data field byte" are parsed out respectively, and the most critical "bytes in the data field of the message frame", "the first data field byte", "Nth data field word" Section" and other key information form the "CANopen data field pool", and the CANopen protocol packaging mechanism encapsulates a "data field" of the "CANopen data field pool" to be transmitted into a complete CANopen message frame.

The Modbus RTU control network sends the Modbus message frame of the gateway. A certain message in the "Modbus data domain pool" obtained through the Modbus unpacking mechanism can be encapsulated into a CANopen message frame through the CANopen packing mechanism, so that it can be further transmitted to the CANopen control. The master station and slave station of the network realize the intercommunication and integration of Modbus RTU to CANopen.

The CANopen message frame sent by the CANopen control network to the gateway, according to the same method, with the intervention of the Modbus packaging mechanism, the intercommunication and integration of CANopen to Modbus RTU can be realized.

The Ethernet interface can encapsulate the messages of the two fieldbus "data fields" into Ethernet message frames to realize the intercommunication and integration of industrial fieldbuses to industrial Ethernet.

According to one or more embodiments, a method for merging heterogeneous industrial field buses is disclosed. Taking two industrial field buses, CANopen and Modbus RTU as examples, other industrial field buses can be easily merged according to the logic shown in this example. As shown in Figure 2 and Figure 3, the following steps are included:

S1. Build the basic environment for Modbus RTU and CANopen protocol implementation based on the set RTOS. RTOS selects XiuOS Industrial Internet of Things Operating System (XiUOS), the open source website is: https://forgeplus.trustie.net/xuos/xiuos, as the protocol of Modbus RTU and CANopen at the application layer, according to the seven-layer reference model of OSI , support RS-485 and CAN peripheral hardware interface calls.

S2. For the heterogeneous industrial field bus protocol, extract the commonality of the realization principle, and abstract it into a field bus adapter model. Taking Modbus RTU and CANopen as an example, the specific steps are as follows:

S21. Construct adapter data structure for industrial fieldbus based on the concept of ubiquitous operating system, including each fieldbus identification ID, registration status, linked data list, callback function, data synchronization semaphore, shared data mutex, network role identifier and other parameters;

S22, call RS485 and CAN peripheral hardware interface;

S23. In the customizable design of the system, the Kconfig tool is integrated to support the code tree and test cases of various industrial fieldbus protocols. The user can configure the fieldbus modules to be used according to the field requirements through the evaluation of the test cases. The bus abstract adapter model maps various configuration options to their own design-specific Kconfig files to ensure that the underlying data structure level is clear.

S3. Build a master/slave control network, use a Modbus master and multiple Modbus slaves to implement a Modbus-type control network according to the established internal logic, and use a CANopen master and multiple CANopen slaves to implement according to the established inherent logic CANopen type control network, specifically:

S31 and Modbus RTU are mostly used between the controller and the actuator, based on which the master/slave control network is constructed;

S32, Modbus RTU correctly transmits control commands and feedback data within a specified time period, including function codes, error codes, check codes, etc.;

S33. The master station builds a response mechanism. When the slave station applies for a connection and sends a broadcast message, the master station wakes up the response thread, and according to the private handshake protocol, compares whether the address field, function code, and error check match. If the connection requirements are met, the master station will The station constructs a feedback message frame, which is received by the slave station and updates the slave station connection information in real time to ensure that the network status is synchronized with the recorded information;

S34, CANopen bus relies on CAN network to process communication interaction. According to the standard CANopen protocol, in terms of data structure, 6 communication objects are designed, including PDO, SDO, SYNC, TIME, EMCY and NMT. These communication objects complete all communication of CANopen protocol. Function.

S4. Based on the Modbus RTU message model and the CANopen message model, with the support of the data structure and processing functions provided by the set RTOS, the master and slave station addresses, identification ID, source node number, destination node number, data domain parameters are obtained by categories ;

S5. Based on the queuing network model, build a packaging and unpacking mechanism for Modbus RTU and CANopen information frames. When a certain industrial application scenario is to continuously exchange data between the two protocols, the management of interactive tasks and buffer management are abstracted into multiple Task multi-queue multi-service mode.

Specifically, when data is continuously exchanged between the two protocols:

S511. A Modbus message frame sent from the control network of Modbus RTU to the gateway, a certain message of the "Modbus data domain pool" obtained through the Modbus unpacking mechanism of the gateway, is encapsulated into a CANopen message frame through the CANopen packing mechanism of the gateway, Thereby, it is further transmitted to the master station and slave station of the CANopen control network, realizing the intercommunication and integration of ModbusRTU to CANopen;

S512, a CANopen message frame sent from the CANopen control network to the gateway, and a certain message of the "CANopen data domain pool" obtained through the CANopen unpacking mechanism of the gateway is encapsulated into a Modbus message frame through the Modbus packing mechanism of the gateway, thereby It is further transmitted to the master station and slave station of the Modbus control network, realizing the intercommunication and integration of CANopen to Modbus RTU.

The mode of abstracting the management of interactive tasks and buffers into multi-task, multi-queue and multi-service is as follows:

表示某一个数据转发请求任务，假设任务依次到达的时刻用…t_-1≤t₀≤t₁≤…表示，则在时刻ti达到的数据分发任务数是N_i，则可以用{t_i，N_i}的行列式描述数据转发任务，若定义每个任务到达时刻的间隙为到达间隔，用F¹(t)表示到达时间间隔的概率分布，f¹(t)表示到达时间间隔的概率密度函数，则

设时刻t到达的转发任务的平均数为N(t)，则转发任务平均到达的速率表示为

若转发任务到达时间间隔服从指数分布时，F¹(t)＝1-e^-λt，f¹(t)＝λe^-λt，1/λ为指数分布的数学期望，即为平均到达间隔，λ为到达率。S521. Suppose there are x types of data domain pools in the system, each type of data domain pool has y data queues to be packaged, and each data queue has z data forwarding requests, where x∈[1, m], y∈[ 1,n], z∈[1,k], m,n,k are natural numbers, use

Represents a certain data forwarding request task. Assuming that the time when the tasks arrive in sequence is represented by ... t _-1 ≤t ₀ ≤t ₁ ≤..., then the number of data distribution tasks reached at time ti is N _i , then {t _i , The determinant of N _i } describes the data forwarding task. If the gap between the arrival times of each task is defined as the arrival interval, F ¹ (t) represents the probability distribution of the arrival time interval, and f ¹ (t) represents the probability density of the arrival time interval. function, then

Let the average number of forwarding tasks arriving at time t be N(t), then the average arrival rate of forwarding tasks is expressed as

If the arrival time interval of forwarding tasks obeys an exponential distribution, F ¹ (t)=1-e ^-λt , f ¹ (t)=λe ^-λt , 1/λ is the mathematical expectation of the exponential distribution, that is, the average arrival interval, λ for the arrival rate.

S522, set the time distribution function of the data forwarding service (that is, the data representing the data domain is packaged into an information frame and successfully forwarded) as F ² (t), and the probability density function as f ² (t), when the service starts and the time elapses After (t), the probability that the service ends in time (dt) immediately can be described as the service rate at time (t), represented by μ(t), μ(t)=P((t<T≤t+dt )|(T≥t)), ie μ(t)=f ² (t)dt/(1−F ² (t)), where T is a random variable of service time. If the service time obeys the exponential distribution, F2(t)=1-e- ^μt , f ² (t)=μe ^-μt , 1/μ is the mathematical expectation of the exponential distribution, that is, the average service time, μ is the service rate .

S523. After describing the arrival situation of the data forwarding task request and the service situation in which the data is successfully forwarded, as information that is relatively easy to obtain in the actual system, it is the necessary input information for the user to evaluate the quality of the data forwarding task. In the data forwarding mechanism, the following auxiliary parameters are mainly considered: at any given moment, suppose the average number of request tasks waiting in the system is W(t), and the average waiting time of a request task is T _W(t) ; T _S(t) is the time interval between when a request task is delivered to the "forwarding thread" and leaves, _Re is the time proportion of the "forwarding thread" running in a certain period of time; _NSW is the waiting time in the system" The sum of the number of tasks served by the "forwarding thread" and the number of tasks being served by the "forwarding thread", denoted T _SW(t) as the sum of the waiting service time and the receiving service time of a request task in the system, that is, T _{SW(t )} = 7 _W(t) +T _S(t) .

So far, the arrival of the request task, the service situation of the "forwarding thread", the independence of the "forwarding thread" and other auxiliary parameters have been analyzed in detail. "Probability distribution of stable operation and high-performance operation, and the results of mathematical analysis are reflected in the XiUOS code tree. Aiming at the troubles caused by the heterogeneity caused by the coexistence of fieldbus standards, and the poor maintainability and reliability caused by the support of the system software corresponding to the fieldbus, a method of heterogeneous industrial fieldbus fusion is proposed. and system, which effectively solves the problem of integration of industrial heterogeneous networks, and has good market prospects and application value. Obviously, the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In the art, the terms involved are as follows.

CAN: Controller Area Network, controller area network, is an ISO international standardized serial communication protocol and one of the most widely used field buses in the world.

CANopen: A high-level communication protocol based on CAN, including communication sub-protocol and device sub-protocol, is a field bus commonly used in industrial control. There are 6 communication objects in the CANopen protocol, namely: PDO (Process Data Object, used to transmit real-time data), SDO (Service Data Object, service processing object, used to access the data dictionary), SYNC (Synchronization , synchronization message, to achieve synchronous transmission of the entire network), TIME (Time Stamp, time stamp message, used to synchronize time), EMCY (Emergency, emergency event message, triggered when an error occurs inside the device), NMT (Network Management Object, network management object, responsible for layer management, network management, ID distribution service), these six communication objects complete all communication functions of the CANopen protocol.

Modbus: A serial communication protocol that has become the industry standard for communication protocols in the industrial field and is now a commonly used connection method between industrial electronic devices. There are two protocols of Modbus in serial bus communication, RTU and ASCII. RTU is the abbreviation of Remote Terminal Unit, which means remote terminal unit. The RTU protocol is to send data directly, binary code, and the physical meaning of its representation needs to be agreed between the sender and the receiver; ASCII is American Standard Code for Information Interchange, which means the United States The standard code for information exchange is a character representation that encodes text editing symbols, uppercase and lowercase letters, numbers and some invisible control characters. Except for the null character, a total of 127 characters are encoded. The data sent by the ASCII protocol is in A binary code for representing a character.

PHY: Port Physical Layer, which can be called port physical layer in Chinese, is a common abbreviation for the physical layer of the OSI model.

RJ-45: The RJ-45 interface is usually used for data transmission, and the most common application is the network card interface.

RS-485: One of the typical serial communication standards. In the industrial communication network, the RS-485 bus is generally used for information transmission and data exchange with various external industrial equipment, and is widely used in many fields.

RDMA: Remote Direct Memory Access, remote direct memory access, RDMA directly transfers data into the computer's memory through the network, and quickly moves the data from one system to the remote system memory without any impact on the operating system, so there is no need to How much computer processing power is used. It eliminates the overhead of data packet copy movement and context switching in user space and kernel space, thus freeing up memory bandwidth and CPU cycles for improving application system performance.

RTOS: Real Time Operating System, real-time operating system.

This specific embodiment is only an explanation of the present invention, and it does not limit the present invention. Those skilled in the art can make modifications without creative contribution to the present embodiment as required after reading this specification, but as long as the rights of the present invention are used All claims are protected by patent law.

Claims (6)

1. A heterogeneous industrial field bus fusion method is characterized by comprising the following steps:

s1, constructing a basic environment realized by Modbus RTU and CANopen protocols based on the set RTOS;

s2, extracting the generality of the implementation principle aiming at the heterogeneous industrial field bus protocol, and abstracting the generality into a field bus adapter model;

s3, constructing master station/slave station control networks which are a Modbus type control network and a CANopen type control network respectively;

s4, acquiring addresses, identification IDs, source node numbers, destination node numbers and data domain parameters of the master station and the slave station in different categories based on a Modbus RTU message model and a CANopen message model under the support of a data structure and a processing function provided by a set RTOS;

s5, constructing a packing and unpacking mechanism of Modbus RTU and CANopen information frames based on a queuing network model, and abstracting the management of interaction tasks and the management of a buffer area into a multi-task multi-queue multi-service mode when a certain industrial application scene is that data is continuously exchanged between two protocols.

2. The heterogeneous industrial field bus fusion method according to claim 1, wherein the step S2 is specifically:

s21, constructing an adapter data structure for the industrial field bus based on the ubiquitous operating system concept, wherein the adapter data structure comprises Identification (ID) of each field bus, a registration state, an associated data linked list, a callback function, data synchronization semaphore, a shared data mutual exclusion lock and a network role identifier parameter;

s22, calling an RS485 and CAN peripheral hardware interface;

s23, integrating a Kconfig tool on the customizable design of the system, supporting code trees and test cases of various industrial field bus protocols, configuring the field bus module to be used according to the field requirement through the evaluation of the test cases, utilizing the field bus abstract adapter model, corresponding various configuration options to the Kconfig files specially designed by the field bus abstract adapter model, and ensuring the clear level of the basic data structure.

3. The heterogeneous industrial field bus fusion method according to claim 1, wherein the step S3 is specifically:

s31, the Modbus RTU is used between the controller and the actuator, and a master station/slave station control network is constructed based on the Modbus RTU;

s32, correctly transmitting control instructions and feedback data including function codes, error codes and check codes by the Modbus RTU in a specified time period;

s33, the master station constructs a response mechanism, when the slave station applies for connection and sends a broadcast message, the master station wakes up a response thread, compares whether the address field, the function code and the error check are matched or not according to a private handshake protocol, if the connection requirement is met, the master station constructs a feedback message frame, receives the feedback message frame by the slave station, updates the connection information of the slave station in real time, and ensures that the network state is synchronous with the recorded information;

s34, the CANopen bus processes communication interaction by depending on the CAN network, 6 communication objects are designed on a data structure according to the standard CANopen protocol, wherein the communication objects comprise PDO, SDO, SYNC, TIME, EMCY and NMT, and all communication functions of the CANopen protocol are completed through the communication objects.

4. The heterogeneous industrial field bus fusion method according to claim 1, wherein the data interaction performed by the two industrial field bus protocols Modbus RTU and CANopen in step S5 specifically comprises:

s511, sending a message frame of Modbus from a control network of Modbus RTU to a gateway, obtaining a certain message of Modbus data domain pool through a Modbus unpacking mechanism of the gateway, and packaging the message frame into a CANopen message frame through a CANopen packaging mechanism of the gateway, so as to further transmit the message frame to a master station and a slave station of the CANopen control network, thereby realizing intercommunication and fusion from the Modbus RTU to the CANopen;

s512, sending a message frame of CANopen from the control network of CANopen to the gateway, obtaining a certain message of 'CANopen data domain pool' through a CANopen unpacking mechanism of the gateway, and packaging the message frame into Modbus through a Modbus packing mechanism of the gateway, thereby further transmitting the message frame to a master station and a slave station of the Modbus control network, and realizing the intercommunication and fusion of CANopen to Modbus RTU.

5. A heterogeneous industrial field bus fusion system is characterized in that: the system comprises a Modbus control network support module, a CANopen control network support module and a gateway support module integrated with a field bus;

the Modbus control network supporting module comprises

A baud rate configuration unit for configuring the baud rate of Modbus master-slave communication,

A transmission mode configuration unit for configuring the protocol supported by Modbus,

Setting a query-response mechanism of master/slave communication of Modbus master station and slave station communication respectively aiming at ' broadcast communication ' and ' point-to-point communication

A slave station message pool used for storing messages sent from each slave station to the master station on the Modbus control network,

A gateway message pool for receiving information of other field buses forwarded by the gateway,

The RS-485 hardware drive supported by the interconnection of the signal receiver and the transmitter is realized through a bottom layer protocol RS-485 of a Modbus RTU;

the CANopen control network supporting module comprises

A baud rate configuration unit for configuring different baud rates of CANopen master-slave communication according to communication distance,

CAN communication object for researching data structure characteristics of process data object, service data object, predefined object, network management object described by CANopen protocol and operation mechanism thereof,

Researching the request-indication-response-confirmation steps of the master-slave communication of the CANopen protocol and the request-indication-response-confirmation mechanism of the control flow,

A slave station message pool used for storing messages sent from each slave station to the master station on the CANopen control network,

Gateway message pool for receiving other fieldbus information forwarded via gateway

Hardware driving of CAN;

the gateway support module integrated with the field bus comprises

A Modbus protocol unpacking mechanism for analyzing the complete Modbus RTU message frame,

A Modbus data domain pool,

A Modbus protocol packing mechanism for packing certain data field information of the Modbus data field pool to be transmitted into a complete Modbus message frame,

A CANopen protocol unpacking mechanism for analyzing the complete CANopen message frame, a CANopen data field pool,

A CANopen protocol packing mechanism for packing a certain data field information of a CANopen data field pool to be transmitted into a complete CANopen message frame,

An Ethernet interface for encapsulating the data field information of the two field buses into Ethernet message frames,

And performing hardware driving of RS-485 and CAN.

6. The heterogeneous industrial fieldbus fusion system of claim 5 wherein:

the Modbus protocol packaging mechanism is specifically that a start bit, an equipment address, a function code, a data field, a CRC check bit and an end symbol of a complete Modbus RTU message frame are respectively analyzed, and a Modbus data field pool is formed by adding the most key data field information and other key information;

the CANopen protocol unpacking mechanism is specifically that a mark, a source node number, a destination node number, a reservation, a byte number of a data field of a complete CANopen message frame, a first data field byte and an Nth data field byte are respectively analyzed, and the most critical byte number of the data field of the message frame, the first data field byte, the Nth data field byte and other key information form a CANopen data field pool.

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