SAE J1939-81:2017 pdf free

SAE J1939-81:2017 pdf free.Network Management
Every CA that transmits messages on a SAE J1939 network shall have a NAME and successfully acquire an address before the CA may transmit normal network traffic. The NAME serves two purposes, first, to provide a functional description of the CA (e.g., Engine Number 1, Engine Number 2, Transmission Number 1, Anti-Lock Brake System 1) and second, to provide a numerical value that may be used in address arbitration.
An address is used within SAE J1939 networks to provide uniqueness to message identifiers and to allow the source of a message to be determined. (Addresses are sometimes referred to as“Source Addresses” indicating the latter use).
Address claim messages, which contain both a source address and a NAME，are used to associate a NAME with a particular address on the network. The association of an address with a unique NAME (4.2.1) also provides means to associate an address with a CA. Manufacturers of ECUs and integrators of networks shall assure that the NAMEs of all CAs intended to transmit on a particular network are unique.
The NAME associated with a CA provides the primary identification of the CA and the function that the CA has on the network. Source addresses in the SAE J1939 network serve as a convenient 8-bit shortcut or alias to identify a particular CA. Address management procedures in the network management protocol allow the association of individual source addresses with the NAME of the CA, and the annunciation of that association onto the network. Appendix C provides examples of the construction of NAMEs for SAE J1939 ECUs.
Each CA on a network shall have one NAME so the CA may be uniquely identified by its primary function. A CA’S NAME is also used in arbitration when multiple CAs attempt to claim the same address, reinforcing the need for unique identification. In turn, each CA on the network shall have a single address which is unique; so that it can properly arbitrate CAN Data Frames with other ECUs.SAE J1939-81 pdf free download.