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/J2178/2_201104 SURFACE VEHICLE RECOMMENDED PRACTICE J2178-2 APR2011 Issued 1993-06 Stabilized
5、2011-04 Superseding J2178-2 JUL2004 Class B Data Communication Network Messages - Part 2: Data Parameter Definitions 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
6、declared “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
7、 CONTENTS1. Scope . 21.1 Standardized Parameter Definitions. 32. References . 42.1 Applicable Publications. 42.1.1 SAE Publications 42.1.2 Other Publications 43. Definitions. 44. Abbreviations and Acronyms 55. General Information 65.1 Part 2 Overview 65.2 How to Use This Document 66. Parameter Refer
8、ence Number (PRN) Structure. 77. Parameter Formats. 97.1 Bit Mapped Parameters 97.1.1 Bit Mapped Data Without Mask Byte(s) 97.1.2 Bit Mapped Data With Mask Byte(s). 107.1.3 Bit Values 117.2 Byte (8 Bit) Parameters 117.3 Word (16 Bit) Parameters . 117.4 Multi-Byte (16 Bit) Parameters . 127.5 Multiple
9、 Parameter Packets 128. Specific Parameter (PRN) Assignments. 128.1 Specific Parameters . 12Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2178-2 Stabilized APR2011 Page 2 of 61 9. Scaling, Lim
10、it, Offset, and Transfer Function (SLOT) Definitions249.1 Multiple Parameter Packeted (PKT) SLOTs249.1.1 Multiple Parameter Packeted Assignments.249.2 Bit Mapped Without Mask (BMP) SLOTs269.2.1 Bit Mapped Without Mask Parameter Assignments309.3 Bit Mapped With Mask Bytes (BMM) SLOTs 309.3.1 Bit Mapp
11、ed With Mask Parameter Assignments.309.4 Unsigned Numeric (UNM) SLOTs.309.4.1 Unsigned Numeric Variable Assignments.319.5 2 Complement Signed Numeric (SNM) SLOTs.339.5.1 2s Complement Signed Numeric Variable Assignments349.6 State Encoded (SED) SLOTs.349.6.1 State Encoded Variable Assignments.349.7
12、ASCII Encoded (ASC) SLOTs409.7.1 ASCII Encoded Variable Assignments409.7.2 ASCII Character Set .429.8 Binary Coded Decimal (BCD) SLOTs 429.8.1 Binary Coded Decimal (BCD) Variable Assignments .429.9 Signed Floating Point (Scientific Notation) (SFP) SLOT .449.9.1 Signed Floating Point Variable Assignm
13、ent 4510. Multiple Frame, Single Parameter Format 4511. Manufacturer PRN Usage by SAE J2178 Part46Appendix A Parameter Name Cross Reference.531. ScopeThis SAE Recommended Practice defines the information contained in the header and data fields ofnon-diagnostic messages for automotive serial communic
14、ations 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 of a SAE J1850 message frame without in-frame response is shown in Figure 1. Thestructu
15、re 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 of emissions related diagnostic message header and data fields. Refer to SAE J2190 for
16、thedefinition of other diagnostic data fields. The description of the network interface hardware, basic protocoldefinition, electrical specifications, and the CRC byte are given in SAE J1850.FIGURE 1SCOPE OF SAE J2178 FOR A SAE J1850 FRAME WITHOUT IN-FRAME RESPONSE (IFR)Copyright SAE International P
17、rovided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2178-2 Stabilized APR2011 Page 3 of 61 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 heade
18、rs. They are the Single Byte header formatand the Consolidated header format. The Consolidated header format has two forms, a single byte form and athree 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
19、 document consists of four parts, each published separately.SAE J2178-1, Part 1 of SAE J2178 (Titled: Detailed Header Formats and Physical Address Assignments)describes the two allowed forms of message header formats, Single Byte and Consolidated. It also containsthe physical node address range assi
20、gnments for the typical sub-systems of an automobile.SAE J2178-2, Part 2 of SAE J2178 (this part, Titled: Data Parameter Definitions) defines the standardparametric data which may be exchanged on SAE J1850 (Class B) networks. The parameter scaling, ranges,and transfer functions are specified. Messag
21、es which refer to these parametric definitions shall always adhereto these parametric definitions. It is intended that at least one of the definitions for each parameter in this partmatch the SAE J1979 definition.SAE J2178-3, Part 3 of SAE J2178 (Titled: Frame IDs for Single Byte Forms of Headers) d
22、efines the messageassignments for the Single Byte header format and the one byte form of the Consolidated header format.SAE J2178-4, Part 4 of SAE J2178 (Titled: Message Definition for Three Byte Headers) defines the messageassignments for the three byte form of the Consolidated header format.1.1 St
23、andardized Parameter DefinitionsThe parameters used to describe data variables are one of the mostimportant functions of this document. To achieve commonality of messages in Class B networks, the dataparameters must become standardized. This applies to data parameter definitions for use during norma
24、lvehicle operations as well as during diagnostic operations. By using common parameter definitions for non-diagnostic and diagnostic functions on the network, the modules which form the network can maintain oneimage or description of a data parameter.At this time however, it is felt that there is no
25、t enough experience and commonality of philosophy within theindustry to define standard parameters. The purpose of this document is therefore to provide standardmethods of defining parameters and examples of defined parameters for many potential applications within avehicle. With this basis, it shou
26、ld be possible to avoid the definition of arbitrarily different parameters and movetoward standard parameters in the future.Where parameters have been defined in the Diagnostic Test Modes, documents (SAE J1979 and J2190), suchas Parameter Identifies for diagnostic purposes, the definitions in Part 2
27、 of this document match the diagnosticdefinition.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2178-2 Stabilized APR2011 Page 4 of 61 SAE J2178-2 defines the parameters to be used for non-diag
28、nostic and diagnostic data format definitions. Fornew parameter definitions which are needed in the future, the new definitions, if they are expected to becomewidely used, must be integrated into this document for commonality across these types of applications. Ofcourse, manufacturers are free to as
29、sign their own definitions to data parameters which are unique orproprietary to their products. They are, however, restricted to using the “Manufacturer Reserved” messageheader assignments in Parts 3 and 4 of this document when using these unique or proprietary data parameterdefinitions.2. Reference
30、s2.1 Applicable PublicationsThe following publications form a part of this specification to the extent specifiedherein. Unless otherwise indicated, the latest issue of SAE publications shall apply.2.1.1 SAE PUBLICATIONSAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE J1213-1
31、Glossary of Vehicle Networks for Multiplex and Data CommunicationSAE J1850Class B Data Communication Network InterfaceSAE J1930Electrical/Electronic Systems Diagnostic Terms, Definitions, Abbreviations, and AcronymsSAE J1979E/E Diagnostic Test ModesSAE J2190Enhanced E/E Diagnostic Test Modes2.1.2 OT
32、HER PUBLICATIONSANSI/IEEE Std 754-1985 August 12, 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 that may include bytes with parameters pertaining to the
33、 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 specificgeographical location or zone of the vehicle,
34、 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 networks, eachframe contains one and only one message (see “mess
35、age” definition).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 definesthe target and source and content of the frame.3.5 Functional Address
36、ingFunctional 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. For example, an exterior lamp “off” message could be sent to all nodesco
37、ntrolling 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 header field, used interchangeably) is a one or three byte field withina fr
38、ame which contains information about the message priority, message source and target addressing,message type, and in-frame response type.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2178-2 St
39、abilized APR2011 Page 5 of 61 3.7 In-Frame Response (IFR) TypeThe IFR type identifies the form of the in-frame response which 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) con
40、tained in the message.3.9 MessageA message consists of all of the bytes of a frame excluding the delimiter symbols (SOF, EOD, EOF,NB).3.10 ModifyThe modify command indicates the operation of using the message data parameter value to change(e.g., increment, decrement, or toggle) the current/existing
41、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 herein.)3.12 Physical AddressingPhysical addressing allows a message t
42、o be addressed to a specific node or to allnodes or to a non-existent, null node. The information in this message is only of relevance to a particular node,so the other nodes on the bus should ignore the message, except for the case of the “all nodes” address.3.13 Primary IDThe primary ID identifies
43、 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 B arbitration process, the message with the highest priority will win
44、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 command to, or a query for data, or action from another node on the network
45、.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 secondary ID (along with the primary ID or Frame ID) identifies the functiona
46、l 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 Acronyms4WD Four (4) Wheel DriveA/C Air ConditioningASC ASCII Encoded SLOTBCD Binary Coded Decimal (BCD) SLOTBMM Bit M
47、apped 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 Vehicle Supply EquipmentCopyright SAE International Provided by IHS under
48、 license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2178-2 Stabilized APR2011 Page 6 of 61 HVACHeating, Ventilation, Air ConditioningID IdentifierIFR In-Frame ResponseLSB Least Significant Bit/ByteMAF Mass Air FlowMIL Malfunction Indicator LampMSB Most Significant Bit/ByteNB Normalization BitPID Parameter Identification (number, NOT the primary ID, see Section 8)PKT Multiple Parameter Packet SLOTPRN Parameter Reference NumberPRNDL Park, Reverse, Neutral, Drive, and Low - IndicatorRPM Revolutions Per Minu
