Basics of CAN bus technology (Controller Area Network)

Introduction to CAN (Control Area Network)

Originally developed by Robert Bosch for automobile in vehicle network Multi-drop,Multi-master serial bus provides communication between controllers,sensors and actuators Very reliable and robust,well proven technology Inexpensive

Standards

CAN 2.0 A -Standard format

CAN 2.0 B -Extended format

International Standard ISO 11898 -ISO 11898-2 high speed applications up to 1 mbps -ISO 11898-3 Low speed applications up to 125 Kbps

Applications of CAN

Automotive Military Vehicle Industrial Machinery Medical Systems Agricultural Machinery Marine control and navigation Elevator Control Systems

CAN Characteristics

All messages are broadcast Any node is allowed to broadcast message Each message contains an ID that identifies the source or content of a message Each receive decided to process or ignore each device

Network Size

The maximum number of nodes is not specified Networks are limited by electrical loading,up to 64 nodes is normal

Four Message Types

1.Data Frame -Used to transmit data

2.Remote Frame -Used to request data transmission

3.Error Frame -Sent by a node that detects an error

4.Overload Frame -Sent by a node to request a delay transmission

Error Detection Capabilities

Bit error Acknowledge error Form error CRC error Stuff error

CAN Architecture

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Control Area Network