CN201072433Y - CAN bus open circuit detection circuit - Google Patents
CAN bus open circuit detection circuit Download PDFInfo
- Publication number
- CN201072433Y CN201072433Y CNU2007200253123U CN200720025312U CN201072433Y CN 201072433 Y CN201072433 Y CN 201072433Y CN U2007200253123 U CNU2007200253123 U CN U2007200253123U CN 200720025312 U CN200720025312 U CN 200720025312U CN 201072433 Y CN201072433 Y CN 201072433Y
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Abstract
The utility model discloses a CAN bus breakage detection circuit which solves the problems that no effective method is found in settling CAN bus breakage, the demand of practical application can not be met, etc., and has the advantages of simple method, convenient application, high rate of accuracy in detection, etc. The utility model has a structure that : the circuit is arranged between an external node and a measured node and comprises a CANH channel and a CANL channel which are positioned between the two nodes; each channel is respectively provided with a control circuit which is composed of two pairs of series resistors and a switch, wherein, a control circuit I of the CANH channel is connected with a RTH end of the measured node and a control circuit II of the CANL channel is connected with a RTL end of the measured node.
Description
Technical field
The utility model relates to the total line detecting method of a kind of CAN, relates in particular to a kind of CAN bus broken circuit detection circuit.
Background technology
The ISO-11898-3 agreement has been stipulated the fault-tolerant type of the fault-tolerant CAN bus of low speed, but does not comprise the detection that CANH and CANL open circuit simultaneously, and auto vendor has when using the fault-tolerant CAN bus of low speed and detects the requirement that CANH and CANL open circuit simultaneously.CAN bus node mode by communication frames when communication is difficult to guarantee the completeness that detects, and node can't detect the situation that CANH and CANL open circuit simultaneously during dormancy.
Summary of the invention
The purpose of this utility model is exactly the effective ways that lack the CAN bus broken circuit at present in order to solve, can not satisfy problems such as practical application needs, provide that a kind of to have method simple, easy to use, detect the CAN bus broken circuit detection circuit and the method thereof of high accuracy for examination.
The utility model adopts following technical scheme for achieving the above object:
A kind of CAN bus broken circuit detection circuit, it is arranged between an external node and tested node, this circuit comprises two internodal CANH passage and CANL passages, be equipped with the resistance of two pairs of series connection and the control circuit that switch is formed on each passage, wherein the control circuit I of CANH passage is connected with the RTH end of tested node; The control circuit II of CANL passage is connected with the RTL of tested node end.
Described control circuit I consists of, and it comprises resistance R 1 and the switch S 3 of connecting with it, and resistance R 1 is connected with the RTH end of tested node, switch S 3 another termination CANH passages, and while switch S 3 also CON3 passage is connected with tested node; Resistance R 4 one ends are connected with power supply, and the other end is connected with switch S 1, should also be connected with tested node through DEC1 by end simultaneously, and this end of switch S 1 then is connected with tested node through the CON1 passage, its another termination CANH passage.
Described control circuit II consists of, and it comprises resistance R 2 and the switch S 4 of connecting with it, and resistance R 2 is connected with the RTL end of tested node, switch S 4 another termination CANL passages, and while switch S 4 also CON4 passage is connected with tested node; Resistance R 3 one ends are connected with power supply, and the other end is connected with switch S 2, should also be connected with tested node through DEC2 by end simultaneously, and this end of switch S 2 then is connected with tested node through the CON2 passage, its another termination CANL passage.
The switch of described switch S 1, S2, S3 and S4 is little with leakage current respectively, and the MOSFET that impedance is big realizes; Described resistance R 3 is selected different intrinsic standoff ratios with R4 according to the requirement of node, and resistance is more than 100K.
Detection method of the present utility model is,
1) system is in dormant state, CANH level=0V under the normal condition, CANL level=12V;
2) control off resistance R1, the R2 by CON3, CON4 passage is connected with bus;
3) control by CON1, CON2 passage is connected to resistance R 4, R3 in the bus;
4) if the bus of detected node was cut off with being connected of external node: because resistance R 1, the disconnection that is connected of R2 and bus, the CANH of detected node and CANL are in open-collector state, because R4, R3 is connected in the bus, and the level of CANH and CANL is by R4, the level of R3 decides, be respectively CANH=1 CANL=0 by DEC1 and the detected bus level of DEC2 in this state, opposite with level under the normal condition, this moment can be judged as CANH and CANL opens circuit;
5) in like manner, if the bus of detected node keeps normal with being connected of external node, when controlling and detecting according to the situation in 4, because the level of external bus can be pulled to normal condition with the level of detected node, so this moment, detected bus level was respectively CANH=0, CANL=1, can be judged as this moment does not have open circuit conditions to take place.
The beneficial effects of the utility model are: circuit structure is simple, and is easy to use, detects accurately quick.
Description of drawings
Fig. 1 is a structural representation of the present utility model.
Wherein, 1. external node, 2. tested node.
Embodiment
The utility model is described in further detail below in conjunction with accompanying drawing and embodiment.
Among Fig. 1, the CAN bus broken circuit detection circuit is arranged on 2 of an external node 1 and tested nodes, this circuit comprises two internodal CANH passage and CANL passages, be equipped with the resistance of two pairs of series connection and the control circuit that switch is formed on each passage, wherein the control circuit I of CANH passage is connected with the RTH end of tested node 2; The control circuit II of CANL passage is connected with the RTL of tested node 2 end.
Control circuit I consists of, and it comprises resistance R 1 and the switch S 3 of connecting with it, and resistance R 1 is connected with the RTH end of tested node, switch S 3 another termination CANH passages, and while switch S 3 also CON3 passage is connected with tested node; Resistance R 4 one ends are connected with power supply, and the other end is connected with switch S 1, should also be connected with tested node through DEC1 by end simultaneously, and this end of switch S 1 then is connected with tested node through the CON1 passage, its another termination CANH passage.
Control circuit II consists of, and it comprises resistance R 2 and the switch S 4 of connecting with it, and resistance R 2 is connected with the RTL end of tested node, switch S 4 another termination CANL passages, and while switch S 4 also CON4 passage is connected with tested node; Resistance R 3 one ends are connected with power supply, and the other end is connected with switch S 2, should also be connected with tested node through DEC2 by end simultaneously, and this end of switch S 2 then is connected with tested node through the CON2 passage, its another termination CANL passage.
The switch of switch S 1, S2, S3 and S4 is little with leakage current respectively, and the big MOSFET of impedance realizes, in order to avoid the state when influencing bus normal communication and dormancy; Described resistance R 3 is selected different intrinsic standoff ratios with R4 according to the requirement of node, and resistance is more than 100K.
Claims (4)
1. CAN bus broken circuit detection circuit, it is arranged between an external node and tested node, it is characterized in that: this circuit comprises two internodal CANH passage and CANL passages, be equipped with the resistance of two pairs of series connection and the control circuit that switch is formed on each passage, wherein the control circuit I of CANH passage is connected with the RTH end of tested node; The control circuit II of CANL passage is connected with the RTL of tested node end.
2. CAN bus broken circuit detection circuit according to claim 1, it is characterized in that: described control circuit I consists of, it comprises resistance R 1 and the switch S 3 of connecting with it, resistance R 1 is connected with the RTH end of tested node, switch S 3 another termination CANH passages, while switch S 3 also CON3 passage is connected with tested node; Resistance R 4 one ends are connected with power supply, and the other end is connected with switch S 1, should also be connected with tested node through DEC1 by end simultaneously, and this end of switch S 1 then is connected with tested node through the CON1 passage, its another termination CANH passage.
3. CAN bus broken circuit detection circuit according to claim 1, it is characterized in that: described control circuit II consists of, it comprises resistance R 2 and the switch S 4 of connecting with it, resistance R 2 is connected with the RTL end of tested node, switch S 4 another termination CANL passages, while switch S 4 also CON4 passage is connected with tested node; Resistance R 3 one ends are connected with power supply, and the other end is connected with switch S 2, should also be connected with tested node through DEC2 by end simultaneously, and this end of switch S 2 then is connected with tested node through the CON2 passage, its another termination CANL passage.
4. according to claim 1 or 2 or 3 described CAN bus broken circuit detection circuits, it is characterized in that: the switch of described switch S 1, S2, S3 and S4 is the MOSFET that leakage current is little, impedance is big; Described resistance R 3 adopts different intrinsic standoff ratios with R4 by the requirement of node, and resistance is being not less than 100K.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200253123U CN201072433Y (en) | 2007-07-20 | 2007-07-20 | CAN bus open circuit detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200253123U CN201072433Y (en) | 2007-07-20 | 2007-07-20 | CAN bus open circuit detection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201072433Y true CN201072433Y (en) | 2008-06-11 |
Family
ID=39550990
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2007200253123U Expired - Fee Related CN201072433Y (en) | 2007-07-20 | 2007-07-20 | CAN bus open circuit detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201072433Y (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100565230C (en) * | 2007-07-20 | 2009-12-02 | 山东省科学院自动化研究所 | CAN bus broken circuit detection circuit and method thereof |
| CN102050363A (en) * | 2010-12-22 | 2011-05-11 | 重庆伊士顿电梯有限责任公司 | High-rise elevator control master command board and control method thereof |
| CN102201961A (en) * | 2011-06-27 | 2011-09-28 | 广州汽车集团股份有限公司 | Fault-tolerant controller area network (CAN) system |
-
2007
- 2007-07-20 CN CNU2007200253123U patent/CN201072433Y/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100565230C (en) * | 2007-07-20 | 2009-12-02 | 山东省科学院自动化研究所 | CAN bus broken circuit detection circuit and method thereof |
| CN102050363A (en) * | 2010-12-22 | 2011-05-11 | 重庆伊士顿电梯有限责任公司 | High-rise elevator control master command board and control method thereof |
| CN102050363B (en) * | 2010-12-22 | 2013-08-28 | 重庆伊士顿电梯有限责任公司 | High-rise elevator control master command board and control method thereof |
| CN102201961A (en) * | 2011-06-27 | 2011-09-28 | 广州汽车集团股份有限公司 | Fault-tolerant controller area network (CAN) system |
| CN102201961B (en) * | 2011-06-27 | 2012-11-07 | 广州汽车集团股份有限公司 | Fault-tolerant controller area network (CAN) system |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20080611 Termination date: 20100720 |