Simulation of a Controller Area Network-based Tractor — Implement Data Bus according to ISO 11783

✍ Scribed by J.W. Hofstee; D. Goense

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 210 KB
• Volume: 73
• Category: Article
• ISSN: 0021-8634
• DOI: 10.1006/jaer.1999.0432

✦ Synopsis

Agricultural machinery in the future will be equipped with a data bus for the exchange of information between di!erent devices such as a task computer, virtual terminal, implement controllers, sensors and actuators. This exchange of information requires standardization. Currently, a working group of the International Organization for Standardization (ISO) is de"ning a standard for a serial control and communications data network for tractors and machinery for agriculture and forestry and is based on controller area network (CAN) Version 2)0B.

A simulation program has been written for a typical agricultural machinery con"guration, equipped with data buses, connected to each other. The simulation program is used to analyse the performance of the network with respect to the transfer time of messages across the network. The transfer time is determined for di!erent bus loads, priorities of the messages and arrangement of the devices.

The simulations showed that the transfer time of messages across the network remains less than 6 ms (maximum observed value) for a typical agricultural machinery con"guration. Increase in load on the implement bus to more than 80% of full capacity can result in transfer times of about 70 ms when the priorities are not properly assigned. This transfer time may be too large for some speci"c applications. When time critical messages are assigned a proper priority, the transfer times of the messages remain less than a few milliseconds, even when the load on the implement bus is high.