SAE J1939 / ISO 11783 Tractor ECU Lecture 7 Tractor ECU ISO 11783 Part 9 BAE 5030 - 353 Spring 2009 Instructor: Marvin Stone Biosystems and Agricultural Engineering Oklahoma State University Feb 18, 2009 BAE 5030-353

Network Context of the TECU Feb 9, 2009 BAE 5030-353

ISO 11783 Tractor Electronic Control Unit (TECU) TECU Functions Transfers data and command messages to/ from the tractor to the implement bus as appropriate for the Tractor ECU’s classification Represents the tractor on the implement bus, including access to the Virtual Terminal Sends requested tractor information on the implement bus Parses messages and commands from the implement bus appropriate for the tractor design Identifies its classification and message set to all ECUs on the implement bus on request using a tractor facilities message (see ISO 11783-7).

ISO 11783 TECU Tractor Classification Specifies Tractor classes of ISOBUS capability A Tractor ECU classification informs the operator of a tractor’s compatibility with implements Each classification identifies a minimum set of messages that a tractor shall provide to connected implements on the implement bus The set of messages a classified Tractor ECU has to provide depends on the tractor’s features The Tractor manufacturer may provide additional messages without providing the complete set of messages of the next higher class of Tractor ECU

Class 1, tractor basic information Shall provide following internal tractor measurements Power management: key switch state; maximum time of tractor power; maintain power request. Speed information: wheel-based implement speed; ground-based implement speed; engine speed: message transmission rate shall be 100 ms. Hitch Information: rear hitch position; rear implement in-work indication. PTO (power take-off) information: rear PTO output shaft speed; rear PTO output shaft engagement.

Class 1, tractor basic information - Continued Lighting: left-turn signal lights; right-turn signal lights; marker light; left stop light; right stop light; implement rear work light. Language-specific parameter storage in tractor ECU, VT or both.

Class 2, enhanced tractor information Shall provide all of the class 1 messages and Time & date, Wheel & ground based distance & direction, Rear hitch draft and lower link forces, Complete set of lighting commands Auxiliary valve (EHRs) estimated and measured status messages

Class 3, command from the connected implement Shall provide all of the class 1 & 2 messages and Rear hitch commands, Rear PTO rpm set-point & engagement commands, Auxiliary valve (EHRs) command messages, An implement or the task controller can request the adjustment of the power source as well as the hitch position A Tractor - Implement combination can perform the same as a self-propelled machine

TECU Additional Features Interface options to TECU classifications 1 to 3 are: Option (F) -- Front hitch & Front PTO Option (N) -- Navigation / location TECU shall also provide the following capabilities: Implement electrical power control Implement lighting control Safe mode operation

ISO 11783 TECU Electrical Connections

ISO 11783 TECU “Fall-Back” for Lighting

Safe-Mode Operation Upon loss of power or communication with the tractor, the implement shall assume a condition of fail-safe operation. The interruption, re-establishment after interruption or fluctuation in any manner whatsoever of the power supply to the implement shall not result in a dangerous situation. Neither shall a fault in the control logic, nor failure or damage to the control circuit, be allowed to lead to danger. Feb 9, 2009 BAE 5030-353

Safe Mode Requirements The implement shall not start unexpectedly. The implement shall not be prevented from stopping if the command has already been given. No part of the implement, or a piece held by the implement, shall fall or be ejected. Automatic or manual stopping of any moving part shall be unimpeded. The protection devices shall remain fully effective. Remote-controlled implements shall be designed and constructed to stop automatically in the event of the driver losing control. The operator shall have the ability to override implement-controlled systems. Feb 9, 2009 BAE 5030-353