CN116800557B - CAN bus fusion communication system based on CANOpen application protocol - Google Patents
CAN bus fusion communication system based on CANOpen application protocol Download PDFInfo
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- CN116800557B CN116800557B CN202311050184.8A CN202311050184A CN116800557B CN 116800557 B CN116800557 B CN 116800557B CN 202311050184 A CN202311050184 A CN 202311050184A CN 116800557 B CN116800557 B CN 116800557B
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- 238000007726 management method Methods 0.000 description 9
- 101100236764 Caenorhabditis elegans mcu-1 gene Proteins 0.000 description 4
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/40—Bus networks
- H04L12/40006—Architecture of a communication node
- H04L12/40013—Details regarding a bus controller
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/40—Bus networks
- H04L12/40169—Flexible bus arrangements
- H04L12/40176—Flexible bus arrangements involving redundancy
- H04L12/40195—Flexible bus arrangements involving redundancy by using a plurality of nodes
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/40—Bus networks
- H04L2012/40208—Bus networks characterized by the use of a particular bus standard
- H04L2012/40215—Controller Area Network CAN
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P90/00—Enabling technologies with a potential contribution to greenhouse gas [GHG] emissions mitigation
- Y02P90/02—Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
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Abstract
The invention discloses a CAN bus fusion communication system based on a CANOpen application protocol, which comprises: the system comprises a programmable controller PLC, a fusion CAN controller and a slave station, wherein the programmable controller PLC is used as a master station and is in communication connection with the slave station through the fusion CAN controller; the integrated CAN controllers comprise a routing table and a plurality of CAN controllers, and each CAN controller is respectively connected with a transmission FIFO, an reception FIFO and a CAN transceiver; and the fusion CAN controller has the following functions: a transmitting function, an accepting function and a CAN controller management function to realize communication between the master station and the slave station. The invention is based on a low-cost PLC controller architecture, N independent CAN controllers are aggregated, a single CAN control channel is provided for users, and a communication system which fuses the N physical CAN controllers into a single CAN controller is provided.
Description
Technical Field
The invention belongs to the technical field of communication, and particularly relates to a CAN bus fusion communication system based on a CANOpen application protocol.
Background
CANOpen is a high-level communication protocol that is built on a control area network (Controller Area Network, CAN), including communication sub-protocols and equipment sub-protocols, which are commonly used in embedded systems, and is also a field bus commonly used by industrial control.
CANOpen implements agreements above (including at) the network layer in the OSI model. The CANopen standard comprises an addressing scheme, several small communication sub-protocols and an application layer defined by the device sub-protocols. CANopen supports network management, equipment monitoring and communication between nodes, including a simple transport layer, segmented delivery of data, and combinations thereof. Generally, the data link layer and the physical layer are implemented by CAN. In addition to CANopen, there are other protocols (e.g., etherCAT) that implement the CANopen device subcontensity.
The prior art is generally implemented in two ways:
(1) As shown in fig. 1, in order to solve the problem of the device capacity and the communication distance of a single CAN bus, the system is implemented by using N programmable controllers (PLCs), namely, the number of slave station devices is M, each programmable controller CAN configure M/N slave stations of total requirements, and then a plurality of programmable controllers form a system by a reconfiguration mode. However, the price of the programmable controllers in the whole system is high, the cost is high, and the slave station devices of the programmable controllers cannot be time synchronized due to no communication connection or non-real-time communication between the programmable controllers in general.
(2) As shown in fig. 2, in order to solve the problem of time synchronization between the slave stations, a more expensive programmable controller (PLC) is selectively configured, N CAN controller modules are configured, and each CAN controller configures M/N slave stations. Although this solution solves the problem of time synchronization, each bus configured device cannot be dynamically switched under another CAN controller, e.g. there is a slave station with address 1 in CAN controller No. 1, a slave station No. 1 in CAN controller No. 2 has no way to access CAN controller No. 1 because address collision occurs.
Disclosure of Invention
The invention aims at: in order to overcome the problems in the prior art, the invention discloses a CAN bus fusion communication system based on a CANOpen application protocol.
The aim of the invention is achieved by the following technical scheme:
a CAN bus converged communication system based on a CANOpen application protocol, the CAN bus converged communication system comprising: the system comprises a programmable controller PLC, a fusion CAN controller and a slave station, wherein the programmable controller PLC is used as a master station and is in communication connection with the slave station through the fusion CAN controller;
the integrated CAN controllers comprise a routing table and a plurality of CAN controllers, and each CAN controller is respectively connected with a transmission FIFO, an reception FIFO and a CAN transceiver;
and the fusion CAN controller has the following functions: a transmitting function, an accepting function and a CAN controller management function to realize communication between the master station and the slave station.
According to a preferred embodiment, the CAN controller management function is configured to record an operating state of each CAN controller, including the CAN controllers: number of transmissions, number of receptions, bus status and error management.
According to a preferred embodiment, the routing table is used to record the source of the path for data transmission and reception.
According to a preferred embodiment, the routing table internal data structure comprises: valid, CAN controller serial number, CANID number, last time; wherein,
the method is effective: indicating whether the current routing table is valid or not, and if so, not querying or modifying the routing table entry;
CAN controller serial number: the CAN controller serial number received by the routing table entry is changed when the data is received last time;
CANID number: the CAN slave station serial number received by the routing table entry is changed when the data is received last time;
the last time: indicating that the data table records the time of receipt of the last burst of CAN data.
According to a preferred embodiment, the timeout execution flow of the routing table includes: when one routing table item is valid, the overtime state machine detects the state of the current routing table; when one routing table item is overtime, the routing table is actively marked as an invalid state, and the overtime state is reported through the management function of the CAN control manager.
According to a preferred embodiment, the sending function of the converged CAN controller is implemented by the following procedure:
when the logic control detects that the transmission data is broadcast data, the broadcast data is transmitted to each CAN controller;
when the logic control detects that the transmission data is unicast data, the routing table is queried, and if the routing information is found, the CAN information is unicast-transmitted into a designated CAN controller; if no routing information is queried, broadcasting is sent to each CAN controller.
According to a preferred embodiment, the receiving function of the converged CAN controller is realized by the following flow: when the logic control detects data reception, the logic controller inquires the routing table, if the routing information is found, the information of the routing table is refreshed, and if the new routing information is not found.
The foregoing inventive concepts and various further alternatives thereof may be freely combined to form multiple concepts, all of which are contemplated and claimed herein. Various combinations will be apparent to those skilled in the art from a review of the present disclosure, and are not intended to be exhaustive or all of the present disclosure.
The invention has the beneficial effects that: the CAN bus integrated communication system is arranged, so that the control performance of the system and the usability of the system are greatly improved, and the requirements of complex requirements such as a large number of devices and dynamic configuration are met. The system reduces the requirement of the PLC performance and the cost of the whole system; the configuration difficulty of the secondary station equipment is reduced, and the level requirements of system maintenance personnel are reduced.
Drawings
FIG. 1 is a conventional multi-CAN architecture;
FIG. 2 is another conventional multi-CAN structure;
FIG. 3 is a schematic diagram of a CAN bus fusion communication system of the invention;
FIG. 4 is a schematic diagram of a routing table data structure in the CAN bus converged communication system of the invention;
FIG. 5 is a flow chart of a routing entry timeout execution in the CAN bus converged communication system of the invention;
FIG. 6 is a schematic diagram of a data transmission flow in the CAN bus converged communication system of the present invention;
FIG. 7 is a schematic diagram of a data receiving flow in the CAN bus converged communication system of the present invention;
fig. 8 is an example of converged communication in accordance with the present invention.
Detailed Description
Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures. In addition, in the present invention, if a specific structure, connection relationship, position relationship, power source relationship, etc. are not specifically written, the structure, connection relationship, position relationship, power source relationship, etc. related to the present invention can be known by those skilled in the art without any creative effort.
Referring to fig. 3, the invention discloses a CAN bus convergence communication system based on a CANOpen application protocol, which comprises: the system comprises a programmable controller PLC, a fusion CAN controller and a slave station, wherein the programmable controller PLC is used as a master station and is in communication connection with the slave station through the fusion CAN controller. The slaves are S1 to Sn in the drawing.
The integrated CAN controllers comprise a routing table and a plurality of CAN controllers, and each CAN controller is respectively connected with a transmission FIFO, an reception FIFO and a CAN transceiver; and the fusion CAN controller has the following functions: a transmitting function, an accepting function and a CAN controller management function to realize communication between the master station and the slave station.
Preferably, the CAN controller management function is configured to record an operating state of each CAN controller, including each CAN controller: number of transmissions, number of receptions, bus status and error management.
Preferably, the routing table is used for recording the route source of data transmission and reception. Referring to fig. 4, the data structure in the routing table includes: valid, CAN controller serial number, CANID number, last time; wherein,
the method is effective: indicating whether the current routing table is valid or not, and if so, not querying or modifying the routing table entry;
CAN controller serial number: the CAN controller serial number received by the routing table entry is changed when the data is received last time;
CANID number: the CAN slave station serial number received by the routing table entry is changed when the data is received last time;
the last time: indicating that the data table records the time of receipt of the last burst of CAN data.
Preferably, referring to fig. 5, the timeout execution flow of the routing table includes: when one routing table item is valid, the overtime state machine detects the state of the current routing table; when one routing table item is overtime, the routing table is actively marked as an invalid state, and the overtime state is reported through the management function of the CAN control manager.
Preferably, referring to fig. 6, the sending function of the converged CAN controller is implemented by the following procedures:
when the logic control detects that the transmission data is broadcast data, the broadcast data is transmitted to each CAN controller;
when the logic control detects that the transmission data is unicast data, the routing table is queried, and if the routing information is found, the CAN information is unicast-transmitted into a designated CAN controller; if no routing information is queried, broadcasting is sent to each CAN controller.
Preferably, referring to fig. 7, the receiving function of the converged CAN controller is implemented by the following procedures: when the logic control detects data reception, the logic controller inquires the routing table, if the routing information is found, the information of the routing table is refreshed, and if the new routing information is not found.
The CAN bus fusion communication system fuses a plurality of CAN controllers into one logic CAN bus controller, provides a single CAN control channel for a programmable controller, and greatly reduces the complexity of a program of the programmable controller and the requirement of system resources.
Further, for field devices, the actual multiple CAN controllers have the same function, and any CAN controller interface CAN be inserted in the configuration process without changing the configuration of the programmable controller. Thus, the on-site engineering configuration is greatly simplified, and the complexity of on-site installation and debugging is reduced.
Moreover, because the plurality of CAN controllers are logically integrated into one logic controller, all other CAN controllers are backups of one CAN controller, and if one CAN controller is damaged, maintenance personnel CAN directly switch to the other CAN controller without changing hardware configuration and software configuration. This greatly reduces the cost of post-maintenance, especially for automated systems maintained by non-professional teams.
Through the CAN bus fusion communication system, the slave station address configuration only needs to be configured to be unique when leaving the factory, the problem of address conflict caused by later address change is avoided, and the maintenance-free slave station number is truly realized under the condition of uncertain slave station number.
Example 1
The embodiment discloses an implementation method of a certain converged CAN controller, and referring to FIG. 8, MCU1 is responsible for maintaining and updating a routing table and controlling a 2-way CAN controller. The MCU2 and the MCU3 have the same function and exchange data with the MCU1 through a local high-speed bus. MCU2 and MCU3 manage 3 way CAN bus controllers respectively. The CAN fusion controller manages 8 CAN controllers in total.
The specific implementation steps are as follows:
firstly, the MCU1 is responsible for initializing communication system parameters, firstly determining whether the communication speed of the CAN controllers in the transmission process is required to realize the CANFD function, and if so, setting the arbitration area of each CAN controller and the communication speed of data. And secondly, determining the filtering parameters of each CAN controller, and determining which data need to be received and which data do not need to be received.
And step two, creating the size of a routing table according to the system configuration, initializing the routing table, and determining the boundary conditions of routing conversion and the setting of routing timeout time. A transmit FIFO and a receive FIFO are created for each CAN bus controller.
And thirdly, when the MCU transmits broadcast data, the logic controller adds the same data to the transmission FIFO of each CAN bus controller, so that each CAN controller CAN transmit the broadcast data to the bus.
And step four, when the MCU transmits unicast data, the logic controller inquires the routing table, and if the routing information is searched, the CAN information is transmitted in a unicast mode to the designated CAN controller FIFO. If no routing information is queried, the broadcast is sent to the transmit FIFO of each CAN control.
And fifthly, when data is received, the MCU1 refreshes the routing information through the ID numbers of the CAN controllers and transmits the data to the programmable logic controller.
And step six, when the number of the secondary stations is not enough to be the maximum number, the MCU inquires whether the secondary stations exist through broadcasting data, and if the secondary stations reply the data, the secondary stations and the new routing information are obtained.
And step seven, when the slave station accesses the bus, the slave station sends notification information, and the MCU receives the information and then follows the new routing information.
And step eight, when the slave station leaves the bus, the MCU updates the routing information according to the overtime state of the routing table.
And step nine, when the slave station changes the bus serial number, the MCU clears the original routing information and updates the new routing information.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (4)
1. A CAN bus fusion communication system based on CANOpen application protocol is characterized in that,
the CAN bus fusion communication system comprises: the system comprises a programmable controller PLC, a fusion CAN controller and a slave station, wherein the programmable controller PLC is used as a master station and is in communication connection with the slave station through the fusion CAN controller;
the integrated CAN controllers comprise a routing table and a plurality of CAN controllers, and each CAN controller is respectively connected with a transmission FIFO, a reception FIFO and a CAN transceiver;
and the fusion CAN controller has the following functions: a transmitting function, a receiving function and a CAN controller management function to realize communication between the master station and the slave station;
the routing table is used for recording the route sources of data transmission and reception;
the data structure in the routing table comprises: valid, CAN controller serial number, CANID number, last time; wherein,
the method is effective: indicating whether the current routing table entry is valid or not, and if the current routing table entry is invalid, not inquiring or modifying the routing table entry;
CAN controller serial number: the CAN controller serial number received by the routing table entry when the data is received last time is represented;
CANID number: the CAN slave station serial number received by the routing table entry when the data is received last time is represented;
the last time: the data table records the receiving time of the last data of the CAN data;
the sending function of the fusion CAN controller is realized through the following flow:
when the logic control detects that the transmission data is broadcast data, the broadcast data is transmitted to each CAN controller;
when the logic control detects that the transmission data is unicast data, the routing table is queried, and if the routing information is found, the CAN information is unicast-transmitted into a designated CAN controller; if no routing information is queried, broadcasting is sent to each CAN controller.
2. The CAN bus convergence communication system as set forth in claim 1, wherein the CAN controller management function is configured to record an operating state of each CAN controller, comprising: number of transmissions, number of receptions, bus status and error management.
3. The CAN bus converged communication system of claim 1, wherein the timeout execution flow of the routing table includes:
when one routing table item is valid, the overtime state machine detects the state of the current routing table; when one routing table item is overtime, the routing table is actively marked as an invalid state, and the overtime state is reported through the management function of the CAN control manager.
4. The CAN bus converged communication system of claim 1, wherein the reception function of the converged CAN controller is realized by the following flow:
when the logic control detects data reception, the logic controller inquires the routing table, if the routing information is found, the information of the routing table is refreshed, and if the new routing information is not found.
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