J1939Training_rev2

J1939 Training Agenda Basic Training: J1939 Vocabulary Basic Training: Monitoring Basic Training: Control Basic Training: Tools / Information Advanced: J1939 message breakdown Advanced: J1939 diagnostic messages Advanced: J1939 multiplexing20021

ummins Industrial Electronics Training

J1939 Training Vocabulary: Datalink: Term used to describe how devices communicate with each other also referred to as a network. Bit: One binary value. A 1 or 0 Byte: 8 bits put together. Ex: 00000001 Bit Field: Number of bits which are grouped together CAN Data Frame: Series of ordered bit fields20022


J1939 Training Vocabulary (cont.) Cyclic Redundancy Check (CRC): Error control mechanism used to detect when a message was corrupted during transimission. Data Field: 0-64 bit field in the CAN data frame which contains the actual data such as oil pressure or coolant temperature as defined in J1939/71 standard.20023


J1939 Training Vocabulary (cont.) Destination Address: Address of who is suppose to receive the message. (not included in all J1939 messages) Global Address is 255 or FF hex

Device: Any physical component which listens to or sends information out on the J1939 datalink. Electronic Control Unit: same as a device20024


J1939 Training Vocabulary (cont.) End of Frame: 7 bit field which marks the end of a CAN frame Extended Frame: A CAN frame which contains a 29 bit identifier as defined in the CAN2.0B standard. Note: J1939 allows both 11bit and 29 bit Identifers to coexist on the same network.


Frame: A series of data bits making up a complete message. The frame contains several bit fields20025

J1939 FrameStart of Frame Bit

ACK FieldHeader # of bytes

End of Frame Bit

8 bytes of actual data

CRC

Priority # PDU Format Source Address

4 bits representing numbers 0-15 typically 8

Actual data you are trying to send

Used for Error Checking


20026

J1939 Training Vocabulary (cont.) Message: One or more CAN data frames which transfer a complete piece of information to other devices on the datalink. Multipacket Message: Messages which require multiple CAN data frames. These are handled by the transport protocol. Protocol: A protocol is the language of how to communicate between devices.20027


J1939 Training Vocabulary (cont.) Parameter Group Number (PGN): a 24 bit identifier used to identify a message which contains a particular group of parameters. Parameter Group: A collection of parameters that are conveyed in a J1939 message. PDU1 Format: Format used when specifying a destination address20028


J1939 Training Vocabulary (cont.) PDU2 Format: Format used when broadcasting information. Priority: The highest priority is zero. Lowest priority is seven. Source Address: Address of who is sending the message on the datalink. Start of Frame: Bit used to indicate the start of a CAN frame.20029


J1939 Training Vocabulary (Cont.) Suspect Parameter Number (SPN): The particular element which is having a problem. This is used in the fault codes to tell us which part is having a problem. (Sensor, ECM, etc..) Failure Mode Identifer (FMI): Used to say how a particular SPN has failed.


200210

J1939 Training


200211

OSI Network Model

Layer Number 7 6 5 4 3 2 1

Application Application Presentation Presentation Session Session Transport Transport Network Network Data Link Data Link Physical Physical Physical Transmission Media200212


OSI Network Model Physical Layer Translates bits to waveforms required by electrical interface

Data Link Layer Adds header and trailer to message for determining if errors occurred in message transmission, start and end of frame, etc...

Network Layer Adds or looks at who sent the message and where the message going

Transport Layer Breaks and reassembles large messages into smaller messages for sending over the network

Session Layer Handles access rights may not want everyone to see all data200213


OSI Network Model Presentation Layer Data encryption, data compression, etc...

Application Layer Whatever is left over from other layers.


200214

OSI Network Model Most protocols do not specify each layer of the OSI model. J1939 does not specify each layer of the model. Currently the following layers are given specific documents in the J1939 standardLayer 1 -- J1939/11 Layer 2 -- J1939/21 Layer 3 -- J1939/31 Layer 7 -- J1939/71 & /73200215


J1939 Training What can I monitor? What must I monitor to remove the indicator lights? Where do I find out how to interpret the messages? Example of reading oil pressure


200216

J1939 Training

Request Only Data

All Module InformationBroadcast Data


200217

J1939 Training What can I monitor? Sensor parameters such as coolant temperature, oil pressure, etc Engine Fault Codes


200218

J1939 Training What must I monitor to remove the indicator lights? All fault code SPNs (suspect parameter number and FMIs (failure mode indicator) must be displayed.


200219

J1939 Training Where do I find out how to interpret the messages? Parameter data messages are found in the J1939/71 standard. Find the PGN first then look up the individual parameter definitions. Fault Code (Diagnostic) messages are found in the J1939/73 standard. You will also need to use the wiring diagram, or AEB for the specific engine to understand what Cummins fault code goes with a SPN / FMI pair.200220


J1939 Control What can the customer control? Engine speed can be controlled via the J1939 datalink. Fan Clutch


200221

J1939 Training High Speed datalinks Reflections & Terminations Topology Troubleshooting


200222

J1939 Training Reflections & Terminations Terminations are required to minimize reflections on the datalink (demo) J1939/11 requires two 120ohm terminations for the datalink. EA options for QSX/QSM only use one 120ohm termination due to the short length between the ECM and the service datalink connection. ICAD Database has more detailed information200223


J1939 Training Circuit block diagram Most of our modules use the Intel 82527 Serial Communcations Controller ( CM500, CENSE, CM550, CM570, etc...) Inside Example circuits shown in J1939/11 ECM specificationMicro ( 68332 ) Serial Communications Controller CAN Transceiver ESD Protection Circuit

Outside ECM


200224

J1939 TopologyLength of Backbone: .1 - 40m Length of Stub: 0 - 1m Maximum number of nodes: 30 Terminations : 120 Minimum Spacing: 0.1 m

Note: Do not equally space the node connections on the backbone120

Stub120

Backbone


200225

J1939 Addressing Dynamic Addressing Each ECM on the network takes on an address at startup. The specific address may be different from startup to startup.

Cummins does not support dynamic addressing; therefore, make sure each device on the datalink has a unique address.200226


J1939 Troubleshooting Troubleshooting First check the termination resistors. Measure resistance between CAN_H and CAN_L. Resistance should be approximately 60 ohms. If you have a small backbone like in the EA options, this may be closer to 120 ohms.

Check for frame errors Using CANalyzer or other tool, monitor the J1939 datalink to see if any frame errors are recorded.200227


J1939 Troubleshooting Troubleshooting (cont.) Monitor broadcast parameters using CANalyzer For multiplexed parameters, verify that the OEM / DOEM is sending the correct source address in the message. Unplug other devices from the datalink so only the PC and ECM are on the network.


200228

J1939 Tools Tools Protocol analyzer Must have a protocol analyzer to develop a datalink interface. Must have the J1939 standard unless customer already has good familiarity with CAN 2.0B protocol.


200229

J1939 Tools CANalyzer In North America contact: Vector CANtech Inc. (248) 449-9290 Matt Palmer Outside America contact: 49-711-80670-505 Lother Felbinger Approximate Cost: Software: $2,700 Hardware: $1,185


200230

J1939 Tools Jpro Cummins owned distributors: Software available through engineering tools (see intranet site: etools.ctg.cummins.com) Hardware available through Industrial Communication Technologies. North America: call (978) 499 - 9271 Outside North America: 49 89 46 1090 Appoximate costs: $910 Non Cummins owned distributors: Software is NOT available through engineering tools. Recommend CANalyzer Jpro support from manufacturer ends 12/01.200231


J1939 Tools Quick Check II available 4th Qtr 2001

J1939 specification Can be ordered online at www.sae.org for $495.00 USD for non-SAE members and $395.00 USD for SAE members.


200232

J1939 Message Breakdown


200233

J1939 FrameStart of Frame Bit

ACK FieldHeader # of bytes

End of Frame Bit

8 bytes of actual data

CRC

Priority # PDU Format Source Address

4 bits representing numbers 0-15 typically 8

Actual data you are trying to send

Used for Error Checking


200234

J1939 29 bit Identifier

CAN Extended S Frame Format O

Identifier 11 bitsPriority

FJ1939 S Frame Format

S I RD RE

Identifier Extension 18 bits

R T R

PDU Format Source RD6 bits (MSB) S I P PDU Specific Destination Address, Address R D F Group Ext, or O P Proprietary R E F 32 1 8 76 5 4 3 2 18 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1

R T R

J1939 Frame bit position 1 2 3 4 5 6 CAN 29 bit ID position

1 1 1 1111 12222222 222333 3 891 1 0 12 3 4 5678 90123456 789012 3 2 2 22 2 2 2 2 2 1 1 1 111111198765 43210 8 7 65 4 3 2 1 0 9 8 7 6543210200235


J1939 29 bit IdentifierHeader Breakdown (29 bits)1 8 F E D F 0 2

1 1000 1111 1110 1101 1111 0000 0010Reserved Data Page 3 bits Priority Number PDU Specific (PS) PDU Format (PF) Contains Destination Address if PF

J1939Training_rev2

Documents

suspect parameter

j1939 troubleshooting

j1939 training

osi network

j1939 training

oil pressure

north america

j1939 framestart