J1939 References...
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Literature on Controller
Area Network
Controller
Area Network (CAN) is a serial network technology that was originally
designed for the automotive industry, especially for European cars, but
has also become a popular bus in industrial automation as well as other
applications. The CAN bus is primarily used in embedded systems, and as
its name implies, is a network technology that provides fast
communication among microcontrollers up to real-time requirements,
eliminating the need for the much more expensive and complex technology
of a Dual-Ported RAM. This book provides complete information on all CAN
features and aspects combined with a high level of readability.
From Wikipedia: J1939
SAE J1939 is the vehicle bus
standard used for communication and diagnostics among vehicle
components, originally by the car and heavy duty truck industry in the
United States. J1939 is used in the commercial vehicle area for
communication in the engine compartment. With a different physical layer
it is used between the tractor and trailer. This is specified in ISO
11992. SAE J1939 defines five layers in the 7-layer OSI network model,
and this includes the CAN 2.0b specification (using only the
29-bit/"extended" identifier) for the physical and data-link layers. The
session and presentation layers are not part of the specification.
Originally, CAN was not mentioned in J1939, which covered cars and
tractor-trailer rigs, and with some dual and triple use 8-bit addresses
assigned by the SAE J1939 board. CAN was not originally free, but its
instruction set did fit in the custom instruction format of J1939. This
was true as of the year 2000. Since then, CAN has been included, the
chipset for J1939 has been clocked faster, and 16-bit addresses (PGN)
have replaced 8-bit addresses.
SAE J1939 Standards
Collection on the Web
SAE's J1939 standards family is the
preferred controller area network (CAN) for equipment used in industries
ranging from agriculture, construction, and fire/rescue to forestry,
materials handling, and on- and off-highway. SAE J1939 Standards
Collection on the Web is an annual subscription service that delivers
web-based access to J1939 documents and related standards and technical
papers.
J1939 is a set of standards defined by SAE. They are used in heavy-duty vehicles (trucks and buses, mobile hydraulics, etc.). In many ways, J1939 is similar to the older J1708 and J1587 standards, but J1939 is built on CAN. The physical layer (J1939/11) describes the electrical interface to the bus. The data link layer (J1939/21) describes the rules for constructing a message, accessing the bus, and detecting transmission errors. The application layer (J1939/71 and J1939/73) defines the specific data contained within each message sent across the network.
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The SAE J1939 standards
| J1939 comprises the following sub standards: | ||
| J1939 | Recommended Practice for a Serial Control & Communications Vehicle Network | |
| J1939/11 | Physical Layer – 250k bits/s, Shielded Twisted Pair | |
| J1939/13 | Off-Board Diagnostic Connector | |
| J1939/21 | Data Link Layer | |
| J1939/31 | Network Layer | |
| J1939/71 | Vehicle Application Layer | |
| J1939/73 | Application Layer – Diagnostics | |
| J1939/81 | Network Management | |
J1939-based
protocol
There are several higher-layer
protocols and profiles, which use the principles of the SAE J1939
specifications. J1939-based higher-layer protocols are mainly used in
diesel power-train applications and in in-vehicle networks for trucks
and buses (e. g. J1939-71/81). Other application fields include:
agriculture and forestry machines (Isobus/ISO 11783), truck/trailer
connection (ISO 11992), military vehicles (MiLCAN A), fleet management
system (FMS), re-creational vehicles (CiA 501/502), and marine
navigation (NMEA2000).
All these sets of specifications describe the protocols for transferring
dedicated parameter groups and segmented data as well as the parameter
groups and the parameters. The base mechanisms are described in the
J1939 set of specifications developed and maintained by the nonprofit
SAE (Society of Automotive Engineers) organization.
ISO 11783 Series
The North American Agricultural
and Construction Industries (CON/AG) published a framework for adding
agriculture-specific messages, which lead to the ISO 11783
standardization activity. The virtual terminal specification within the
ISO 11783 standard was pre-developed in Germany by the LAV non-profit
organization (part of VDMA, Verband Deutscher Maschinen- und Anlagenbau).
The ISO 11783 standard is also known as Isobus.
