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0198441113586, V2.01, 11.2008
IL•1F CANopen DS301 3 Basics
Fieldbus interface 15
3Basics
3.1 CANopen technology
3.1.1 CANopen description language
CANopen is a device- and manufacturer-independent description lan-
guage for communication via the CAN bus. CANopen provides a com-
mon basis for interchanging commands and data between CAN bus
devices.
3.1.2 Communication layers
CANopen uses the CAN bus technology for data communication.
CANopen is based on the basic network services for data communica-
tion as per the ISO-OSI model model. 3 layers enable data communica-
tion via the CAN bus.
• Physical Layer
• Data Link Layer
• Application Layer
Figure 3.1 CANopen layer model
Physical Layer The physical layer defines the electrical properties of the CAN bus such
as connectors, cable length and cable properties such as bit-coding and
bit-timing.
Data Link Layer The data link layer connects the network devices. It assigns priorities to
individual data packets and monitors and corrects errors.
Application Layer The application layer uses communication objects (COB) to exchange
data between the various devices. Communication objects are elemen-
tary components for creating a CANopen application.
device communication
fielb bus communication
application Layer
data Link Layer
physical Layer
CAN-Bus