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 there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2011 SAE International All rights reserved. No part of this publication m
3、ay 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 (outside U
4、SA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedbackon this Technical Report, please visit http:/www.sae.org/technical/standards/J2178/1_201104 SURFACE VEHICLE RECOMMENDED PRACTICE J2178-1 APR2011 Issued 1992-06 Stabilized
5、2011-04 Class B Data Communication Network Messages - Detailed Header Formats and Physical Address Assignments RATIONALE The technical report covers technology, products, or processes which are mature and not likely to change in the foreseeable future. STABILIZED NOTICE This document has been declar
6、ed “Stabilized“ by the SAE Vehicle Architecture for Data Communications Standards Committee and will no longer be subjected to periodic reviews for currency. Users are responsible for verifying references and continued suitability of technical requirements. Newer technology may exist. TABLE OF CONTE
7、NTS1. Scope . 22. References . 32.1 Applicable Publications. 33. Definitions. 34. Abbreviations and Acronyms 35. General Information 55.1 Part 1 Overview 55.2 In-Frame Response Field Formats. 66. Single Byte Header Messages and Format 77. Consolidated Header Messages and Format. 87.1 One Byte Form o
8、f the Consolidated Header Format 87.2 Three Byte Form of the Consolidated Header Format . 88. Data Field Formats. 118.1 Functional Data Fields Formats 118.2 Physical Data Field Formats. 148.3 Extended Addressing . 159. Physical Address Assignments 17Appendix A Network Architectures and Header Select
9、ion. 18Superseding J2178-1 JUL2004 Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2178-1 Stabilized APR2011 Page 2 of 19 1. ScopeThis SAE Recommended Practice defines the information contained
10、in the header and data fields ofnon-diagnostic messages for automotive serial communications based on SAE J1850 Class B networks. Thisdocument describes and specifies the header fields, data fields, field sizes, scaling, representations, and datapositions used within messages.The general structure o
11、f a SAE J1850 message frame without in-frame response is shown in Figure 1. Thestructure of a SAE J1850 message with in-frame response is shown in Figure 2. Figures 1 and 2 also show thescope of frame fields defined by this document for non-diagnostic messages. Refer to SAE J1979 forspecifications o
12、f emissions related diagnostic message header and data fields. Refer to SAE J2190 for thedefinition of other diagnostic data fields. The description of the network interface hardware, basic protocoldefinition, the electrical specifications, and the CRC byte are given in SAE J1850.FIGURE 1SCOPE OF SA
13、E J2178 FOR A SAE J1850 FRAME WITHOUT IN-FRAME RESPONSE (IFR)FIGURE 2SCOPE OF SAE J2178 FOR A SAE J1850 FRAME WITH IN-FRAME RESPONSE (IFR)SAE J1850 defines two and only two formats of message headers. They are the Single Byte header formatand the Consolidated header format. The Consolidated header f
14、ormat has two forms, a Single Byte form anda three byte form. This document covers all of these formats and forms to identify the contents of messageswhich could be sent on a SAE J1850 network.This document consists of four parts, each published separately.SAE J2178-1 (Titled: Detailed Header Format
15、s and Physical Address Assignments) describes the two allowedforms of message header formats, Single Byte and Consolidated. It also contains the physical node addressrange assignments for the typical sub-systems of an automobile.SAE J2178-2 (Titled: Data Parameter Definitions) defines the standard p
16、arametric data which may beexchanged on SAE J1850 (Class B) networks. The parameter scaling, ranges, and transfer functions arespecified. Messages which refer to these parametric definitions shall always adhere to these parametricdefinitions. It is intended that at least one of the definitions for e
17、ach parameter in this part matches the SAEJ1979 definition.SAE J2178-3 (Titled: Frame IDs for Single Byte Forms of Headers) defines the message assignments for thesingle byte header format and the one byte form of the consolidated header format.SAE J2178-4 (Titled: Message Definition for Three Byte
18、Headers) defines the message assignments for thethree byte form of the consolidated header format.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2178-1 Stabilized APR2011 Page 3 of 19 2. Refere
19、nces2.1 Applicable PublicationsThe following publications form a part of this specification to the extent specifiedherein. Unless otherwise specified, the latest issue of SAE publications shall apply.2.1.1 SAE PUBLICATIONSAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE J121
20、3-1Glossary of Vehicle Networks for Multiplex and Data CommunicationSAE J1850Class B Data Communication Networks InterfaceSAE J1930Electrical/Electronic Systems Diagnostic Terms, Definitions, Abbreviations, and AcronymsSAE J1979E/E Diagnostic Test ModesSAE J2190Enhanced E/E Diagnostic Test Modes2.1.
21、2 ANSI/IEEE PUBLICATIONAvailable from ANSI, 25 West 43rd Street, New York, NY 10036-8002.ANSI/IEEE 754-1985IEEE Standard for Binary Floating-Point Arithmetic3. Definitions3.1 Data Data FieldData and data field are used interchangeably in this document and they both refer to a fieldwithin a frame tha
22、t may include bytes with parameters pertaining to the message and/or secondary ID and/orextended addresses and/or test modes which further defines a particular message content being exchangedover the network.3.2 Extended AddressThe extended address is a means to allow a message to be addressed to a
23、geographicallocation (such as geographic) or zone of the vehicle, independent of any nodes physical address.3.3 FrameA frame is one complete transmission of information which may or may not include an In-FrameResponse. The frame is enclosed by the start of frame and end of frame symbols. For Class B
24、 networks, eachframe contains one and only one message (see “message“ definition below).3.4 Frame IDThe Frame ID is the header byte for the Single Byte Header format and the one byte form of theconsolidated header format. The definition of the frame ID is found in SAE J2178-3. This header byte defin
25、esthe target and source and content of the frame.3.5 Functional AddressingFunctional addressing allows a message to be addressed or sent to one or morenodes on the network interested in that function. Functional addressing is intended for messages that may beof interest to more than a single node. F
26、or example, an exterior lamp “off“ message could be sent to all nodescontrolling the vehicle exterior lamps by using a functional address. The functional address consists of aprimary ID and may include a secondary ID and may also include an extended address.3.6 Header Header FieldThe header (or head
27、er field, used interchangeably) is a one or three byte field withina frame which contains information about the message priority, message source and target addressing,message type, and in-frame response type.3.7 In-Frame Response (IFR) TypeThe IFR type identifies the form of the in-frame response wh
28、ich is expectedwithin that message.3.8 LoadThe load command indicates the operation of directly replacing the current/existing value of aparameter with the parameter value(s) contained in the message.3.9 MessageA message consists of all of the bytes of a frame excluding the delimiter symbols (SOF, E
29、OD, EOF,NB).Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2178-1 Stabilized APR2011 Page 4 of 19 3.10 ModifyThe modify command indicates the operation of using the message data parameter value
30、 to change(e.g., increment, decrement, or toggle) the current/existing value.3.11 ParameterA parameter is the variable quantity included in some messages. The parameter value, scaling,offset, units, transfer function, etc., are unique to each particular message. (The assigned parameters arecontained
31、 herein.)3.12 Physical AddressingPhysical addressing allows a message to be addressed to a specific node or to allnodes or to a non-existent, null node. The information in this message is of relevance only to a particular node,so the other nodes on the bus should ignore the message, except for the c
32、ase of the “all nodes“ address.3.13 Primary IDThe primary ID identifies the target for this functional message. This is the primary discriminatorused to group functions into main categories.3.14 PriorityThe priority describes the rank order and precedence of a message. Based upon the SAE J1850,Class
33、 B arbitration process, the message with the highest priority will win arbitration.3.15 ReportA report indicates the transmission of parametric data values, based on: a change of state; a changeof value; on a periodic rate basis; or as a response to a specific request.3.16 RequestA request is a comm
34、and to, or a query for data, or action from another node on the network.3.17 Response DataThe response data is the information from a node on the network in response to a requestfrom another node on the network. This may be an in-frame response or a report type of message.3.18 Secondary IDThe second
35、ary ID (along with the primary ID or Frame ID) identifies the functional target nodefor a message. The purpose of the secondary ID field within the frame is to further define the function or actionbeing identified by the primary ID.4. Abbreviations and AcronymsA/C - Air ConditioningASC - ASCII Encod
36、ed SLOTBCD - Binary Coded Decimal (BCD) SLOTBMM - Bit Mapped with Mask SLOTBMP - Bit Mapped without Mask SLOTCRC - Cyclic Redundancy CheckCS - ChecksumDTC - Diagnostic Trouble CodeEOD - End of DataEOF - End of FrameERR - Error DetectionEV-ETS - Electric Vehicle Energy Transfer SystemEVSE - Electric
37、Vehicle Supply EquipmentHVAC - Heating, Ventilation, Air ConditioningID - IdentifierIFR - In-Frame ResponseLSB - Least Significant Bit/ByteMSB - Most Significant Bit/ByteNB - Normalization BitPID - Parameter IDentification (number, NOT the primary ID, (See Section 7)PKT - Multiple Parameter Packet S
38、LOTPRN - Parameter Reference NumberSED - State Encoded SLOTCopyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2178-1 Stabilized APR2011 Page 5 of 19 SFP - Signed Floating Point (Scientific Notation
39、) SLOTSLOT - Scaling, Limit, Offset, and Transfer Function (See Section 8)SNM - 2s Complement Signed Numeric SLOTSOF - Start of FrameUNM - Unsigned Numeric SLOTVIN - Vehicle Identification Number5. General Information5.1 Part 1 OverviewThe messages defined by this four part document are specified fo
40、r networks using singlebyte headers or consolidated one and three byte headers as specified in SAE J1850. Sections 6 and 7 of SAEJ2178-1 provide the system architecture for the different possible headers used in Class B networkcommunication (see Appendix A for supporting discussion). Section 8 of SA
41、E J2178-1 defines the data fieldsused by the different header byte formats. Section 9 of SAE J2178-1 defines the physical addressassignments.Figure 3 shows an overview of this part (Part 1) which encompasses the different possible messages and theircomponent parts.FIGURE 3PART 1 OVERVIEWCopyright SA
42、E International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2178-1 Stabilized APR2011 Page 6 of 19 SAE J1850 defines two and only two formats of message headers. They are the Single Byte header formatand the Consolidat
43、ed header format. The Consolidated header format has two forms, identified by the value ofthe H Bit. The two forms are: a one byte form and a three byte form. The information in the header field forboth formats contains target, source, priority and message type information, while the data field cont
44、ainsadditional addressing and/or parametric information and/or diagnostic test modes. This information is explicitlydefined in some headers and implicitly defined in others. Messages defined by this document (Parts 1, 2, 3,and 4) are classified generally into two types:a. Requests, that is, commands
45、 (load or modify) or queries for data, andb. Responses, that is, reports or acknowledgments.When a node generates a request, the target nodes which are responsible for the requested data or functionmust respond by reporting the requested information or by performing the requested function. For respo
46、nses(that is, reports or acknowledgments), data information that a node responds with may have been previouslyrequested by another node, or reported by the node when the desired information has changed, or reported bythe node on a periodic basis.SAE J2178-1 describes the overall structure of message
47、s. In total, parts 1, 2, 3, and 4:a. Fully define SAE (automotive industry) standard messages.b. Reserve messages for future SAE standardization.c. Reserve messages for manufacturers to allocate, which are typically unique or proprietary to thatmanufacturer.In order to comply with this document, imp
48、lementations need to use the defined messages on SAE J1850networks in the exact way that they are defined here. However, there are a large number of message codesthat are reserved for each manufacturer to independently allocate.5.2 In-Frame Response Field FormatsThe total number of bytes in the frame (not including frame delimiters) is12, including the header (1 or 3 depending on header type), data (both in the message and IFR), and singlebyte CRC. Therefore, the total number of message and IFR data bytes can be 10 if using a single byte headeror the one byt
