Basics of CAN bus technology (Controller Area Network)


#1

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


#2

CAN Architecture

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Control Area Network

CAN Bus configuration-ISO 11898