CN109412918A - A kind of CAN communication system - Google Patents
A kind of CAN communication system Download PDFInfo
- Publication number
- CN109412918A CN109412918A CN201811267393.7A CN201811267393A CN109412918A CN 109412918 A CN109412918 A CN 109412918A CN 201811267393 A CN201811267393 A CN 201811267393A CN 109412918 A CN109412918 A CN 109412918A
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- Prior art keywords
- hub
- port
- controller
- bus
- foot
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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
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/25—Arrangements specific to fibre transmission
- H04B10/2589—Bidirectional transmission
- H04B10/25891—Transmission components
-
- 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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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Optical Communication System (AREA)
Abstract
The present invention provides a kind of CAN communication system, conventional twisted pair is replaced by optical fiber, and using the reception foot in CAN controller and foot is sent instead of CAN transceiver, to solve traditional CAN node device using twisted pair interconnection data transfer distance between by electromagnetic environment and cable locating for bus parasitic capacitance influenced, the limited problem of data transmission distance, CAN controller is to the communication of node device up to 200 meters or more.In addition, the damage of any one CAN hub of bottom will not influence the communication of other modules, each first CAN hub can disengage the 2nd CAN hub and individually control.
Description
Technical field
The present invention relates to CAN communication technical fields.More particularly, to a kind of CAN communication system.
Background technique
CAN is a kind of using the fieldbus for realizing serial multi-host communication without destructive position competition mechanism.It is anti-due to having
Interference performance is strong, message is short, real-time good advantages, the CAN bus such as low with networking cost are widely used in bad environments, electricity
Magnetic radiation is big, to fields such as the industrial automation scenes and automobile component control that reliability requirement is high.Most common CAN bus object
Managing layer transmission medium is twisted pair.ISO11898-2 defines the high-speed CAN bus physical layer standard using twisted pair as medium.?
In CAN bus, the achievable flank speed of network is related with the size of bus.Such as when length of cable is not more than 40m Shi Keshi
Existing flank speed is 1Mb/s.In actual use, following reason, which will cause highest, can realize the decline of rate: in bus
The node of access excessively causes bus parameter mismatch；The over-voltage over-current protection circuit installed additional on node causes bus parameter mismatch；
The Regional Distribution of node is excessive, and too long of cable causes bus parameter mismatch.In addition, the working environment when bus is excessively severe,
When exceeding the maximum value that physical layer transceiver device allows such as the common mode potential difference between node, bus can not be worked normally, tradition
CAN node device uses the shadow of twisted pair interconnection data transfer distance parasitic capacitance between by electromagnetic environment and cable locating for bus
It rings, data transmission distance is limited, and longest is only 40 meters or so, therefore there are many restrictions.
Summary of the invention
In order to solve current CAN node device using twisted pair interconnection data transfer distance by electromagnetic environment locating for bus with
The influence of parasitic capacitance between cable, the limited problem of data transmission distance, the present invention provide a kind of CAN communication system.
In certain embodiments, a kind of CAN communication system communicates to connect, the system packet with multiple CAN node devices
It includes:
Controller is corresponded with each CAN node device, and the controller includes receiving foot and transmission foot；
Multiple first CAN hubs, each first CAN hub include several one-to-one first ports and second end
Mouthful；
Optical fiber makes any one first port pair of the reception foot and one of them the first CAN hub of each controller
It should connect, the transmission foot of each controller is connect with the one-to-one second port of any one first port；
2nd CAN hub, including several one-to-one first ports and second port, the first CAN hub
In any one not connected controller first port by the optical fiber and the 2nd CAN hub one of them first
Port connection, the corresponding second port of the first CAN hub second port corresponding with the 2nd CAN hub connect.
In certain embodiments, each first port of the first CAN hub and the 2nd CAN hub with it is corresponding
Second port is the interconnection of line and logic.
In certain embodiments, each first port of the first CAN hub and the 2nd CAN hub with it is corresponding
Second port is interconnected by FPGA Programmadle logic device or the realization of CPLD Programmadle logic device.
In certain embodiments, each first CAN hub connects five CAN node devices.
In certain embodiments, the first port is the port " T ", and the second port is the port " R ".
In certain embodiments, the first CAN hub and the 2nd CAN hub are 18 mouthfuls of CAN hubs.
In certain embodiments, the first CAN hub and the 2nd CAN hub are surrounded by metal shell.
Beneficial effects of the present invention are as follows:
The present invention provides a kind of CAN communication system, conventional twisted pair is replaced by optical fiber, and utilize CAN controller
In reception foot and send foot instead of CAN transceiver, to solve traditional CAN node device using twisted pair internet data
Transmission range between by electromagnetic environment and cable locating for bus parasitic capacitance influenced, the limited problem of data transmission distance, CAN control
Device processed is to the communication of node device up to 200 meters or more.In addition, the damage of any one CAN hub of bottom will not influence other
Module communication, each first CAN hub can disengage the 2nd CAN hub and individually control.
Detailed description of the invention
Specific embodiments of the present invention will be described in further detail with reference to the accompanying drawing.
Fig. 1 shows the circuit connection diagram of CAN communication system in the prior art.
Fig. 2 shows the structural schematic diagrams of CAN communication system in the embodiment of the present invention.
Fig. 3 shows the structural schematic diagram of the first CAN hub and the 2nd CAN hub in Fig. 2.
Specific embodiment
In order to illustrate more clearly of the present invention, the present invention is done further below with reference to preferred embodiments and drawings
It is bright.Similar component is indicated in attached drawing with identical appended drawing reference.It will be appreciated by those skilled in the art that institute is specific below
The content of description is illustrative and be not restrictive, and should not be limited the scope of the invention with this.
The various sectional views for disclosing embodiment according to the present invention are shown in the attached drawings.These figures are not drawn to scale
, wherein some details are magnified for the purpose of clear expression, and some details may be omitted.It is shown in the drawings
Various regions, the shape of layer and relative size, positional relationship between them are merely exemplary, in practice may be due to system
It makes tolerance or technical restriction and is deviated, and those skilled in the art may be additionally designed as required with not similar shape
Shape, size, the regions/layers of relative position.
Conventional CAN local area network interior joint is interconnected using Shielded Twisted Pair, traffic rate by length of twisted pair influenced with
Inversely, bus communication speed can also be under microwave, high-power electromagnetic environment rugged environment for length of twisted pair
One step reduces, so bus physical layer ideally uses fiber optic communication.
CAN protocol is to define intermediate several layers of agreement, and physical layer is not formulated, and can be optical fiber, coaxial electrical
Cable or twisted pair, as long as meeting the logic of dominant bit and recessive position, the transmission pin of CAN controller is only responsible for bus
Dominant bit is sent, pin is received and is only responsible for detecting the dominant bit of bus and recessive position, two pins are all Transistor-Transistor Logic level, CAN transmitting-receiving
Device is that two pins and bus of controller are connected as shown in Figure 1.
In order to solve current CAN node device using twisted pair interconnection data transfer distance by electromagnetic environment locating for bus with
The influence of parasitic capacitance between cable, the limited problem of data transmission distance, the present invention provide a kind of CAN communication system.The present invention
A kind of CAN communication system is provided, is communicated to connect with multiple CAN node devices, the system comprises: controller (does not show in figure
Out), it is corresponded with each CAN node device, the controller includes receiving foot and transmission foot；Multiple first CAN hubs
(the CAN level-one hub in corresponding diagram), each first CAN hub includes several one-to-one first ports and second end
Mouthful；Optical fiber makes the reception foot of each controller is corresponding with any one first port of one of them the first CAN hub to connect
It connects, the transmission foot of each controller is connect with the one-to-one second port of any one first port；2nd CAN hub
(the CAN second level hub in corresponding diagram), including several one-to-one first ports and second port, the first CAN collection
The first port that any one in line device is not connected with controller passes through one of them of the optical fiber and the 2nd CAN hub
First port connection, the corresponding second port of the first CAN hub second port company corresponding with the 2nd CAN hub
It connects.
The present invention provides a kind of CAN communication system, conventional twisted pair is replaced by optical fiber, and utilize CAN controller
In reception foot and send foot instead of CAN transceiver, to solve traditional CAN node device using twisted pair internet data
Transmission range between by electromagnetic environment and cable locating for bus parasitic capacitance influenced, the limited problem of data transmission distance, CAN control
Device processed is to the communication of node device up to 200 meters or more.In addition, the damage of any one CAN hub of bottom will not influence other
Module communication, each first CAN hub can disengage the 2nd CAN hub and individually control.
" recessiveness " position and " dominant " position according to the regulation in relation to standard, at CAN controller and transceiver pin TX and RX
Signal level be respectively defined as high level " 1 " and low level " 0 ".Correspondingly differential voltage Vcanh-Vcaml > 0 is fixed in bus
Justice is " dominant " position, and Vcanh-Vcaml≤0 is defined as " recessiveness " position.
When multiple node competition bus controls, bus arbitration position (ID number) signal that sending node issues is in bus
After the position signal " line with " sent with other nodes, the end RX for being sent to the controller of each node (also includes sending node sheet
Body), guarantee the state that all nodes can listen in bus." recessiveness " position (is completed) by CAN transceiver in bus and " is shown
Property " result of position " line with " is " dominant " position；" recessiveness " position and " recessiveness " position " line and " remain as " recessiveness " position, ensure that CAN
Realization of the mostly main nondestructive position competition bus arbitration mechanism of bus in CAN controller.
Furthermore, position arbitration, response bits and the erroneous frame transmission mechanism intrinsic due to CAN bus message, data bit signal
Transmission direction can change in same data frame, therefore appear in each data bit in bus and must advise
It is properly received in the fixed time by all nodes (including sending node itself) in bus, communication can be just normally carried out.This
Feature also determines the relationship that the network radius of CAN bus and traffic rate are inversely proportional.
3 of twisted pair media CAN bus transceiver completion physical layer signal transmission work are mainly characterized in that: in summary
1) signal of " recessiveness " position and " dominant " position is reasonably defined at pin TX, RX of CAN controller and in bus
Level；
2) " line with " of a signal is able to achieve when multinode sends data；
3) all nodes (including sending node) all must be able to the position signal listened in bus at any time.
Therefore, in certain embodiments, as shown in figure 3, each of the first CAN hub and the 2nd CAN hub
First port is the interconnection of line and logic with corresponding second port.In a particular embodiment, in certain embodiments, described
Each first port of one CAN hub and the 2nd CAN hub is interconnected by FPGA editable with corresponding second port
Logical device.It is of course also possible to be realized by CPLD Programmadle logic device.The present embodiment by CAN hub realize line with
Logic does not need to add additional device, has saved cost and volume.In certain embodiments, each first CAN hub connects
Connect five CAN node devices.Each first CAN hub evenly distributes.
In certain embodiments, the first port is the port " T ", and the second port is the port " R ".That is T (x) and R
(x)。
In certain embodiments, the first CAN hub and the 2nd CAN hub are 18 mouthfuls of CAN hubs.
In certain embodiments, the first CAN hub and the 2nd CAN hub are surrounded by metal shell, with protection
Internal circuit.
In a specific embodiment, CAN communication system provided by the invention is monitored using the power module of Mr. Yu's equipment
In system, system needs to export HIGH-POWERED MICROWAVES, and total output is made of 50 power modules, and the output of modules passes through
Synthesizer is brought together, it is desirable that the input of each module, output, working condition need real-time report, and control system is according to mould
The data that block reports, which export it, to be finely adjusted.Realize that intermodule communicates with each other using CAN bus based on the above feature system, by
Strong microwave environment is in bus, and conventional method uses twisted pair to often result in CAN node as communication media to crash and be detached from
Bus causes to perplex to system control, and this system is attempted to use optical fiber as data transmission media and achieve good for the first time
Control effect, system have used three 18 mouthfuls of CANCAN hubs, and logical device uses ALTERA company in CAN hub
MAX7128 is done as controller, and optical fiber receiver-transmitter module uses the optical fiber transceiving of HFBR-2412, HFBR1414 of Avago company
Module, module driver use the TC4429 bootrom of TI company, and system debugs successfully that solve CAN total by optical fiber wiring
Line communication interference issues, the length that communication controller between and power module thoroughly does away with optical fiber have reached 200 meters, above to prove this
Method efficiently solves interference and the communication length limitation problem of CAN.
Belong to " first ", " second " etc. in description and claims of this specification and above-mentioned attached drawing are for distinguishing
Different objects, is not use to describe a particular order.In addition, term " includes " and " having " and their any deformations, meaning
Figure, which is to cover, non-exclusive includes.Such as contain the process, method, system, product or equipment of a series of steps or units
It is not limited to listed step or unit, but optionally further comprising the step of not listing or unit, or optionally also
Including the gas step intrinsic for these process, methods or equipment or unit.
Obviously, the above embodiment of the present invention be only to clearly illustrate example of the present invention, and not be pair
The restriction of embodiments of the present invention may be used also on the basis of the above description for those of ordinary skill in the art
To make other variations or changes in different ways, all embodiments can not be exhaustive here, it is all to belong to this hair
The obvious changes or variations that bright technical solution is extended out are still in the scope of protection of the present invention.
Claims (7)
1. a kind of CAN communication system is communicated to connect with multiple CAN node devices, which is characterized in that the system comprises:
Controller is corresponded with each CAN node device, and the controller includes receiving foot and transmission foot；
Multiple first CAN hubs, each first CAN hub include several one-to-one first ports and second port；
Optical fiber makes the reception foot of each controller is corresponding with any one first port of one of them the first CAN hub to connect
It connects, the transmission foot of each controller is connect with the one-to-one second port of any one first port；
2nd CAN hub, including several one-to-one first ports and second port are appointed in the first CAN hub
One of first port that the first port of one not connected controller of meaning passes through the optical fiber and the 2nd CAN hub
Connection, the corresponding second port of the first CAN hub second port corresponding with the 2nd CAN hub connect.
2. system according to claim 1, which is characterized in that the first CAN hub and the 2nd CAN hub it is every
A first port is the interconnection of line and logic with corresponding second port.
3. system according to claim 1, which is characterized in that the first CAN hub and the 2nd CAN hub it is every
A first port is interconnected by FPGA Programmadle logic device or CPLD Programmadle logic device with corresponding second port
It realizes.
4. system according to claim 1, which is characterized in that each first CAN hub connects five CAN nodes and sets
It is standby.
5. system according to claim 1, which is characterized in that the first port is the port " T ", and the second port is
The port " R ".
6. system according to claim 1, which is characterized in that the first CAN hub and the 2nd CAN hub are ten
Eight mouthfuls of CAN hubs.
7. system according to claim 1, which is characterized in that the first CAN hub and the 2nd CAN hub surround
There is metal shell.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811267393.7A CN109412918A (en) | 2018-10-29 | 2018-10-29 | A kind of CAN communication system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811267393.7A CN109412918A (en) | 2018-10-29 | 2018-10-29 | A kind of CAN communication system |
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| Publication Number | Publication Date |
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| CN109412918A true CN109412918A (en) | 2019-03-01 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201811267393.7A Pending CN109412918A (en) | 2018-10-29 | 2018-10-29 | A kind of CAN communication system |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040143697A1 (en) * | 2003-01-16 | 2004-07-22 | Mahowald Peter H. | Communication module configurable with firmware and related method |
| CN101834674A (en) * | 2010-03-31 | 2010-09-15 | 中国航空工业集团公司西安飞机设计研究所 | Method for building dual-redundancy optical fiber CAN bus network |
| CN102026050A (en) * | 2009-09-18 | 2011-04-20 | 华中科技大学 | Optical fiber CAN bus hub and networking method thereof |
| WO2012105811A2 (en) * | 2011-02-01 | 2012-08-09 | Taejin Info Tech Co., Ltd. | Raid-based storage control board |
-
2018
- 2018-10-29 CN CN201811267393.7A patent/CN109412918A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040143697A1 (en) * | 2003-01-16 | 2004-07-22 | Mahowald Peter H. | Communication module configurable with firmware and related method |
| CN102026050A (en) * | 2009-09-18 | 2011-04-20 | 华中科技大学 | Optical fiber CAN bus hub and networking method thereof |
| CN101834674A (en) * | 2010-03-31 | 2010-09-15 | 中国航空工业集团公司西安飞机设计研究所 | Method for building dual-redundancy optical fiber CAN bus network |
| WO2012105811A2 (en) * | 2011-02-01 | 2012-08-09 | Taejin Info Tech Co., Ltd. | Raid-based storage control board |
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Application publication date: 20190301 |