SAE J 1939-11-2016 Physical Layer 250 Kbps Twisted Shielded Pair.pdf

1、_SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising theref

2、rom, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions.Copyright 2016 SAE InternationalAll rights reserved. No part of this publi

3、cation may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE.TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada)Tel: +1 724-776-4970 (out

4、side USA)Fax: 724-776-0790Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedback on thisTechnical Report, please visithttp:/standards.sae.org/J1939/11_201612SURFACE VEHICLERECOMMENDED PRACTICEJ1939-11 DEC2016Issued 1994-12Revised 2016-12Superseding

5、J1939-11 SEP2012Physical Layer, 250 Kbps, Twisted Shielded PairRATIONALEDocument is revised to allow additional color combinations to denote SAE J1939 networks, to clarify connector pin labeling, and update references and terminology for consistency with ISO 11898-1:2015.FOREWORDThe set of SAE J1939

6、 Recommended Practice documents define a high speed ISO 11898 CAN protocol based communications network that can support real-time closed loop control functions, simple information exchanges, and diagnostic data exchanges between Electronic Control Units (ECUs) physically distributed throughout the

7、vehicle.The SAE J1939 communications network is developed for use in heavy-duty environments and suitable for use in horizontally integrated vehicle industries. The physical layer aspects of SAE J1939 reflect its design goal for use in heavy-duty environments. Horizontally integrated vehicles involv

8、e the integration of different combinations of loose package components, such as engines and transmissions, which are sourced from many different component suppliers. The SAE J1939 common communication architecture strives to offer an open interconnect system that allows the ECUs associated with dif

9、ferent component manufacturers to communicate with each other.The SAE J1939 communications network is intended for light-duty, medium-duty, and heavy-duty vehicles used on-road or off-road, and for appropriate stationary applications which use vehicle derived components (e.g., generator sets). Vehic

10、les of interest include, but are not limited to, on-highway and off-highway trucks and their trailers, construction equipment, and agricultural equipment and implements.This set of SAE Recommended Practices has been developed by the SAE Truck and Bus Control and Communications Network Committee of t

11、he SAE Truck and Bus Electrical and Electronics Steering Committee. The SAE J1939 communications network is defined using a collection of individual SAE J1939 documents based upon the layers of the Open System Interconnect (OSI) model for computer communications architecture. These SAE J1939 documen

12、ts are intended as a guide toward standard practice and are subject to change to keep pace with experience and technical advances.SAE INTERNATIONAL J1939-11 DEC2016 Page 2 of 32TABLE OF CONTENTS1. SCOPE 42. REFERENCES 42.1 Applicable Documents 43. NETWORK PHYSICAL DESCRIPTION . 53.1 Physical Layer.

13、53.2 Physical Media 53.3 Differential Voltage 53.4 Bus Levels. 53.5 Bus Levels During Arbitration . 53.6 Common Mode Bus Voltage Range . 53.7 Bus Termination 63.8 Internal Resistance . 63.9 Differential Internal Resistance . 63.10 Internal Capacitance . 63.11 Differential Internal Capacitance. 63.12

14、 Bit Time . 63.13 Internal Delay Time. 93.14 CAN Bit Timing Requirements 94. FUNCTIONAL DESCRIPTION . 115. ELECTRICAL SPECIFICATION . 115.1 Electrical Data . 115.1.1 Electronic Control Unit 115.1.2 Bus Voltages - Operational . 135.1.3 Electrostatic Discharge (ESD) 135.1.4 Example Physical Layer Circ

15、uits. 135.2 Physical Media Parameters 135.2.1 Bus Line 135.2.2 Topology . 155.2.3 Terminating Resistor. 165.2.4 Split termination of backbone 165.2.5 Shield Termination 175.2.6 ECU Type I and Type II Markings. 175.3 Connector Specifications 175.3.1 Connector Electrical Performance Requirements. 185.

16、3.2 Connector Mechanical Requirements. 186. CONFORMANCE TESTS. 206.1 Recessive Output of the ECUs . 206.2 Internal Resistance of CAN_H and CAN_L 206.3 Internal Differential Resistance . 216.4 Recessive Input Threshold of an ECU 216.5 Dominant Output of an ECU . 226.6 Dominant Input Threshold of an E

17、CU . 226.7 Internal Delay Time. 227. DISCUSSION OF BUS FAULTS 237.1 Loss of Connection to Network . 237.2 Node Power or Ground Loss 237.3 Unconnected Shield 237.4 Open and Short Failures. 248. NOTES 268.1 Revision Indicator 26SAE INTERNATIONAL J1939-11 DEC2016 Page 3 of 32APPENDIX A EXAMPLE CIRCUITS

18、 . 27APPENDIX B RECOMMENDED CABLE TERMINATION PROCEDURE 29APPENDIX C RECOMMENDED CABLE SPLICE PROCEDURE 30APPENDIX D RECOMMENDED CABLE REPAIR PROCEDURE 32FIGURE 1 PHYSICAL BIT REPRESENTATION 5FIGURE 2 PHYSICAL LAYER FUNCTIONAL . 7FIGURE 3 ILLUSTRATION OF INTERNAL CAPACITANCE AND RESISTANCE OF AN ECU

19、 IN THE RECESSIVE STATE. 8FIGURE 4 ILLUSTRATION OF DIFFERENTIAL INTERNAL CAPACITANCE AND RESISTANCE OF ANECU IN THE RECESSIVE STATE . 8FIGURE 5 PARTITION OF THE BIT 8FIGURE 6 CABLE CROSS-SECTION . 14FIGURE 7A NETWORK TOPOLOGY (TYPE I ECUS ONLY) 15FIGURE 7B WIRING NETWORK TOPOLOGY (ONE TYPE II ECU IN

20、STALLED) 15FIGURE 7C WIRING NETWORK TOPOLOGY (TWO TYPE II ECUS INSTALLED). 16FIGURE 8 AN EXAMPLE OF NETWORK CONNECTOR USAGE 18FIGURE 9 STUB CONNECTOR (WITH MALE KEY) DIMENSIONAL REQUIREMENTS (A). 19FIGURE 10 THROUGH CONNECTOR (WITH FEMALE KEY) DIMENSIONAL REQUIREMENTS (B) . 19FIGURE 11 MEASUREMENT O

21、F VCAN_H AND VCAN_L DURING THE BUS IDLE STATE . 20FIGURE 12 MEASUREMENT OF RIN WHILE THE ECU PROTOCOL IC IS SET TO BUS IDLE. 20FIGURE 13 MEASUREMENT OF RDIFF WHILE THE ECU PROTOCOL IC IS SET TO BUS IDLE 21FIGURE 14 TESTING THE INPUT THRESHOLD FOR RECESSIVE BIT DETECTION 21FIGURE 15 MEASUREMENT OF VC

22、AN_H AND VCAN_L WHILE THE ECU SENDS A DOMINANT BIT. 22FIGURE 16 TESTING THE INPUT THRESHOLD FOR DOMINANT BIT DETECTION 22FIGURE 17 MEASUREMENT OF THE INTERNAL DELAY TIME TECU BY PARTLY OVERWRITING THE FIRST RECESSIVE IDENTIFIER BIT (SHADED AREA) BY A DOMINANT LEVEL UNTIL THE ARBITRATION IS LOST. 23F

23、IGURE 18 POSSIBLE FAILURES DUE TO EXTERNAL EVENTS . 25FIGURE A1 EXAMPLE PHYSICAL LAYER CIRCUIT 27FIGURE A2 CIRCUIT WITH EXTERNAL BACKBONE TERMINATION 28FIGURE A3 CIRCUIT WITH INTERNAL BACKBONE SPLIT TERMINATION 28FIGURE B1 CABLE TERMINATION. 29FIGURE B2 FINISHED ASSEMBLY. 29FIGURE C1 CABLE SPLICE. 3

24、0FIGURE C2 SEALED CABLE SPLICE-FINISHED ASSEMBLY. 31FIGURE D1 CABLE REPAIR 32FIGURE D2 CABLE SPLICE-FINISHED ASSEMBLY 32TABLE 1 EXAMPLE BIT TIMING PARAMETERS. 9TABLE 2 AC PARAMETERS OF AN ECU DISCONNECTED FROM THE BUS LINE . 10TABLE 3 LIMITS OF VCAN_H AND VCAN_L OF AN ECU DISCONNECTED FROM THE BUS L

25、INE FOR NOMINAL BATTERY VOLTAGES OF 12 V AND 24 V 11TABLE 4 DC PARAMETERS FOR THE RECESSIVE STATE OF AN ECU DISCONNECTED FROM THE BUS LINE - RECESSIVE STATE . 12TABLE 5 DC PARAMETERS FOR THE DOMINANT STATE OF AN ECU DISCONNECTED FROM THE BUS LINE - DOMINANT STATE. 12TABLE 6 BUS VOLTAGE PARAMETERS FO

26、R THE RECESSIVE STATE WITH ALL ECUS CONNECTED TO THE BUS LINE - RECESSIVE STATE. 12TABLE 7 BUS VOLTAGE PARAMETERS FOR THE DOMINANT STATE WITH ALL ECUS CONNECTED TO THE BUS LINE - DOMINANT STATE 13TABLE 8 PHYSICAL MEDIA PARAMETERS FOR TWISTED SHIELDED CABLE 14TABLE 9 NETWORK TOPOLOGY PARAMETERS. 16TA

27、BLE 10 TERMINATING RESISTOR PARAMETERS 16TABLE 11 CONNECTOR PARAMETERS . 18SAE INTERNATIONAL J1939-11 DEC2016 Page 4 of 321. SCOPEThis document defines a physical layer having a robust immunity to EMI and physical properties suitable for harsh environments.CAN controllers are available which support

28、 the CAN Flexible Data Rate Frame Format. These controllers, when used on SAE J1939-11 networks, must be restricted to use only the Classical Frame Format compliant to ISO 11898-1:2015.These SAE Recommended Practices are intended for light- and heavy-duty vehicles on- or off-road as well as appropri

29、ate stationary applications which use vehicle derived components (e.g., generator sets). Vehicles of interest include but are not limited to: on- and off-highway trucks and their trailers; construction equipment; and agricultural equipment and implements.2. REFERENCES2.1 Applicable DocumentsThe foll

30、owing publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the latest issue of SAE publications shall apply.2.1.1 SAE PublicationsAvailable from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA a

31、nd Canada) or +1 724-776-4970 (outside USA), www.sae.org.SAE J1113-13 Electromagnetic Compatibility Measurement Procedure for Vehicle Components -Part 13: Immunity to Electrostatic DischargeSAE J1128 Low Voltage Primary CableSAE J1939 Serial Control and Communications Heavy Duty Vehicle Network - To

32、p Level DocumentSAE J1939-13 Off-Board Diagnostic ConnectorSAE J1939-16 Automatic Baud Rate Detection SAE AS85485 Cable, Electric, Filter Line, Radio Frequency Absorptive2.1.2 ISO PublicationsCopies of these documents are available online at http:/webstore.ansi.org/ISO 11898-1:2015 Road vehicles - C

33、ontroller area network (CAN) - Part 1: Data link layer and physical signallingISO 11898-2:2016 Road vehicles - Controller area network (CAN) - Part 2: High-speed medium access unit.ISO 6722-1 Road vehicles - 60 V and 600 V single-core cables - Part 1: Dimensions, test methods andrequirements for cop

34、per conductor cablesSAE INTERNATIONAL J1939-11 DEC2016 Page 5 of 323. NETWORK PHYSICAL DESCRIPTION3.1 Physical LayerThe physical layer is a realization of an electrical connection of a number of ECUs (Electronic Control Units) to a network. The total number of ECUs will be limited by electrical load

35、s on the bus line. This maximum number of ECUs is fixed to 30, on a given segment, due to the definition of the electrical parameters given in the present specification3.2 Physical MediaThis document defines a physical media of shielded twisWHGSDLU7KHVHZLUHVKDYHDFKDUDFWHULVWLFLPSH GDQFHRIand are sym

36、metrically driven with respect to the electrical currents. The designations of the individual wires are CAN_H and CAN_L. The names of the corresponding pins of the ECUs are also denoted by CAN_H and CAN_L, respectively. The third connection for the termination of the shield is denoted by CAN_SHLD.3.

37、3 Differential VoltageThe voltages of CAN_H and CAN_L relative to ground of each individual ECU are denoted by VCAN_H and VCAN_L. Thedifferential voltage between VCAN_H and VCAN_L is defined by Equation 1:L_CANH_CANdiff VVV (Eq. 1)3.4 Bus LevelsThe bus lines can have one of the two logical states, r

38、ecessive or dominant (see Figure 1). In the recessive state, VCAN_Hand VCAN_L are fixed to a mean voltage level. Vdiff is approximately zero on a terminated bus. The recessive state is transmitted during bus idle or a recessive bit.The dominant state is represented by a differential voltage greater

39、than a minimum threshold. The dominant state overwrites the recessive state and is transmitted during a dominant bit.3.5 Bus Levels During ArbitrationA dominant and recessive bit imposed on the bus lines during a given bit time by two different ECUs will result in a dominantbit.Figure 1 - Physical b

40、it representation3.6 Common Mode Bus Voltage RangeThe common mode bus voltage is defined as the boundary voltage levels of CAN_H and CAN_L, measured with respect to the individual ground of each ECU, for which proper operation is guaranteed when all ECUs are connected to the bus line.SAE INTERNATION

41、AL J1939-11 DEC2016 Page 6 of 323.7 Bus TerminationThe bus line is electrically terminated at each end with a load resistor denoted by RL (see Figure 2). Type I ECUs shall not contain the bus termination resistor RL. Type II ECUs shall contain the bus termination resistor or split termination, and i

42、f used shall be located only at one or both ends of a network. Type II ECUs shall be clearly marked as specified in Section 5.2.5. (Also see 5.2.3 for resistor characteristics.)3.8 Internal ResistanceThe internal resistance, Rin, of an ECU is defined as the resistance between CAN_H (or CAN_L) and gr

43、ound during the recessive state, with the ECU disconnected from the bus line (see Figure 3).3.9 Differential Internal ResistanceThe differential internal resistance, Rdiff, is defined as the resistance between CAN_H and CAN_L during the recessive state, with the ECU disconnected from the bus line (s

44、ee Figure 4).3.10 Internal CapacitanceThe internal capacitance, Cin, of an ECU is defined as the capacitance between CAN_H (or CAN_L) and ground during the recessive state, with the ECU disconnected from the bus line (see Figure 3).3.11 Differential Internal CapacitanceThe differential internal capa

45、citance, Cdiff, of an ECU is defined as the capacitance between CAN_H and CAN_L during the recessive state, with the ECU disconnected from the bus line (see Figure 4).3.12 Bit TimeThe nominal bit time, tB, (duration of one bit in the arbitration phase) and data bit time, tD, (duration of one bit in

46、the data phase) for this document is 4 microseconds corresponding to 250 kbps. Bus management functions executed within this bit time, such as ECU synchronization behavior, network transmission delay compensation, and sample point positioning, are defined by the programmable bit timing logic of the

47、CAN protocol IC (Integrated Circuit). See Figure 5.Various names for the bit segments are used by suppliers of CAN protocol ICs and it is possible that two bit segments are defined as one.SAE INTERNATIONAL J1939-11 DEC2016 Page 7 of 32Figure 2 - Physical layer functionalSAE INTERNATIONAL J1939-11 DE

48、C2016 Page 8 of 32Figure 3 - Illustration of internal capacitance and resistance of an ECU in the recessive stateFigure 4 - Illustration of differential internal capacitance and resistance of an ECU in the recessive stateFigure 5 - Partition of the bita. SYNC SEG - This part of the bit time is used

49、to synchronize the various ECUs on the bus. An edge is expected within this bit segment.b. PROP SEG - This part of the bit time is used to compensate for the physical delay times within the network. These delay times are caused by the propagation time of the bus line and the internal delay time of the ECUs.c. PHASE SEG1, PHASE SEG2 - These Phase-