The Difference Between CANopen vs DeviceNet Protocols: A Practical Guide for Industrial Automation Engineers

Industrial communication protocols are the backbone of modern automation systems. They determine how controllers, sensors, drives, and actuators exchange data reliably in real time. Among the many fieldbus technologies available, CANopen and DeviceNet remain two widely used protocols built on the Controller Area Network (CAN) standard. At first glance, they appear similar—both are CAN-based, both are used in industrial automation, and both support device-level communication. But in practice, they differ significantly in architecture, flexibility, ecosystem, and application use.
This guide breaks down the real-world differences between CANopen and DeviceNet, helping you understand when to use each and how they impact system design.
Understanding CANopen and DeviceNet Protocols
Before comparing them directly, it’s important to understand what each protocol is and how it fits into industrial automation. Both CANopen and DeviceNet are higher-layer protocols built on top of the CAN bus, which provides the physical and data link layers for communication. However, they define different rules for:

Data structure
Device communication
Network behavior
System integration

What Is CANopen?

CANopen is an open communication protocol developed by the CAN in Automation (CiA) organization. It standardizes how devices communicate over a CAN network by defining structured communication models, device profiles, and data organization. One of its defining features is the object dictionary, which organizes all device parameters, configuration data, and communication variables in a standardized way. CANopen is widely used in:

Motion control systems
Embedded automation
Robotics
Machine control

Its strength lies in flexibility and customization, allowing engineers to tailor communication behavior to specific applications.
What Is DeviceNet?
DeviceNet is an industrial network protocol originally developed by Allen-Bradley (Rockwell Automation) and later standardized by the ODVA (Open DeviceNet Vendor Association). It is based on the Common Industrial Protocol (CIP) and uses CAN as its physical communication layer. DeviceNet is primarily designed for:

Industrial I/O communication
Factory automation systems
PLC-based control networks

Unlike CANopen, DeviceNet emphasizes plug-and-play interoperability, making it easier to integrate devices from multiple vendors into a single system.
CANopen vs DeviceNet: Core Differences
Although both protocols share the same CAN foundation, their differences become clear when you examine how they handle communication, system design, and scalability.
1. Protocol Architecture and Standardization
The most fundamental difference lies in how each protocol is structured.
CANopen is a highly flexible, open standard maintained by CiA, allowing engineers to customize communication features and device behavior based on application needs. DeviceNet, on the other hand, follows a more rigid, standardized architecture based on CIP, ensuring consistent implementation across devices.
Key Insight

CANopen = Flexible and customizable
DeviceNet = Standardized and structured

This distinction has a direct impact on system design and integration.
2. Network Flexibility and Customization
CANopen is designed with flexibility in mind. Engineers can select only the features required for a specific application, optimizing performance and reducing unnecessary complexity. DeviceNet is less flexible but more predictable. Its strict specifications ensure that devices behave consistently, which simplifies integration.
Practical Implication

CANopen is better for custom machine design and complex systems
DeviceNet is better for standardized factory environments

3. Device Interoperability and Ecosystem

DeviceNet excels in interoperability due to its strict physical and communication standards. Devices from different manufacturers can be easily integrated into the same network. CANopen, while also standardized, allows more variation in implementation. This flexibility can sometimes require additional configuration during integration.
Key Takeaway

DeviceNet = Easier multi-vendor integration
CANopen = Greater flexibility, but requires more engineering effort

4. Network Size and Scalability

CANopen supports up to 127 nodes on a network, while DeviceNet typically supports up to 64 nodes. This makes CANopen more suitable for larger distributed systems.
Real-World Impact

CANopen works well in large, distributed machine networks
DeviceNet is commonly used in smaller, localized control systems

5. Communication Model and Data Handling

CANopen uses structured communication methods such as:

Process Data Objects (PDOs) for real-time data
Service Data Objects (SDOs) for configuration
Network Management (NMT) for device control

These features provide a highly organized communication framework. DeviceNet uses a producer-consumer communication model based on CIP, which allows efficient data exchange between devices.
Key Difference

CANopen = Structured communication with object dictionaries
DeviceNet = CIP-based data exchange model

6. Physical Layer and Wiring

Although both protocols use CAN, DeviceNet defines stricter physical requirements, including:

Cable types
Network topology
Power distribution

This enables DeviceNet to supply both data and power over the same cable, simplifying installation. CANopen offers more flexibility in physical implementation but requires more design consideration.
7. Application Focus
CANopen is widely used in:

Motion control systems
Embedded devices
Robotics
Custom machinery

DeviceNet is commonly used in:

PLC-based systems
Factory automation
Industrial I/O networks

Summary

CANopen = Engineering flexibility and advanced control
DeviceNet = Simplicity and standardization

Key Similarities Between CANopen and DeviceNet

Despite their differences, these protocols share several important characteristics. Both are:

Based on the CAN bus
Designed for real-time communication
Used in industrial automation
Suitable for connecting sensors, actuators, and controllers

However, they are not directly compatible, and communication between them requires a protocol gateway.
CANopen vs DeviceNet: Practical Comparison Table

Feature	CANopen	DeviceNet
Standard Organization	CiA (CAN in Automation)	ODVA
Protocol Type	Open, flexible	Standardized (CIP-based)
Max Nodes	Up to 127	Up to 64
Flexibility	High	Moderate
Interoperability	Moderate	High
Communication Model	Object dictionary (PDO/SDO)	Producer-consumer (CIP)
Physical Layer	Flexible	Strict specifications
Typical Use	Motion control, embedded systems	Factory automation, I/O control