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SAE J1939 / ISO 11783 Network Management. Lecture 5 Network Management ISO 11783 Part 5, J1939-81 BAE 5030 - 353 Spring 2009 Instructor: Marvin Stone Biosystems and Agricultural Engineering Oklahoma State University. Purpose of Network Management. Describes
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SAE J1939 / ISO 11783 Network Management Lecture 5 Network Management ISO 11783 Part 5, J1939-81 BAE 5030 - 353 Spring 2009 Instructor: Marvin Stone Biosystems and Agricultural Engineering Oklahoma State University BAE 5030-353
Purpose of Network Management • Describes • the management of source addresses and the association of those addresses with the actual functional identification of a device • the detection and reporting of network related errors. • initialization processes • requirements for reaction to brief power outages • minimum requirements for network connected electronic control units. • Provides methods for distributed management of addresses and identity (no master). BAE 5030-353
Network Management Functions • Defines NAMEs for ECUs • Provides hierarchical naming structure • Three Hierarchical Levels • Device Class -> function-> ECU • Provides instance count for each level • Provides identification of manufacturer of ECU • Provides type IDs for Class and Function • Defines address configuration types • ECU Address configuration • Configurable Address • Service Configurable Address • Command Configurable Address • Self-Configurable Address ECU • (J1939) Arbitrary address capable BAE 5030-353
Network Management Functions • Defines ECU types • Standard • Diagnostic/Development Tool • Network Interconnection • Defines address initialization process • Defines address commanding process • Defines power continuity requirements • ISO and J1939 are different BAE 5030-353
Messages defined for Network Management • Request for Address Claim • Normal Request Message of the Address Claim PGN • Address Claim • Commanded Address • Cannot Claim • Address Claim of the Null Address (254) BAE 5030-353
Messages for address management Always sent to Global! BAE 5030-353
NAMEing - ECU Identity within the network • ECUs have a NAME and address (numeric ID) • Address • Provides unique identity within a session • Included in every message to provide message uniqueness • NAME • Provides high probability of a unique identifier within a connected system • Provides some functional identification of ECUs • Used to arbitrate in the case of an address selection conflict BAE 5030-353
NAME Structure BAE 5030-353
NAME Hierarchy BAE 5030-353
NAME Example • Second ECU of a Rate Control unit on third Planter • Self-Configuring - True = 1 • Industry Group - Agriculture and Forestry = 2 • Device Class - Planter/Seeders = 4 • Device Class Instance - Third Planter = 2 • Function - Rate Control (undefined) = 255 • Function Instance - First undefined = 0 • ECU Instance - Second ECU = 1 BAE 5030-353
Initialization Process • Given in the text of the document • Following figures • Provides distributed methods for ECUs to secure the use of an address • Provides processes for both self and non-self configuring ECUs BAE 5030-353
State Transitions for self-configuring ECUs BAE 5030-353
State Transitions for Non-Self-configuring ECUs BAE 5030-353
NAME-Address Table Maintenance • Addresses of ECUs may change • May occur on initialization (initial address conflict) • New ECUs are added since last power-up • Could occur during operation • New ECUs are powered during operation • Self-Configuring ECUs lose conflicts with non-Self-Configuring ECUs • Self-Configuring bit in NAME gives non-self-configuring ECUs priority • Change of Addresses of ECUs rare • ECUs retain successfully claimed address for next power-up • Changes occur on re-configuration BAE 5030-353
NAME-Address Table Maintenance • Must maintain current “NAME to Address” relationship • For ECUs to which destination specific messages are sent • Commands, Requests • May need current “NAME to Address” relationship • For ECUs that are Listened to • If the information is sender dependent • Procedure • Listen to address claims • Update table for those of interest • Maintain across power disruptions BAE 5030-353
Reaction to Power Supply Voltage Disturbances and Interruptions • < 10 ms, interruptions spaced by at least 100 ms: • NO Loss of normal network communications nor loss of in-process messages. • NO Processor reset. • NO Loss of data in volatile memory, including network configuration information and/or messages in progress over the network. • > 1s • Power is not restored within 1 second then the ECU must reset and complete a Power On Self Test (POST). • Between 10ms and 1s • Internal requirements determine if a reset is required. BAE 5030-353