solderic.com CANopen and DeviceNet are two prominent communication protocols used in industrial automation for networking devices; CANopen offers flexibility and scalability suitable for complex, multi-vendor systems, while DeviceNet focuses on simplicity and ease of integration primarily in Rockwell Automation environments. Explore the rest of the article to understand which protocol best fits your specific automation needs and applications.
Comparison Table
| Feature | CANopen | DeviceNet |
|---|---|---|
| Protocol Type | Higher-layer CAN protocol | Higher-layer CAN protocol |
| Standard | CiA 301 (CAN in Automation) | ODVA (Open DeviceNet Vendors Association) |
| Application Focus | Industrial automation, medical, railway | Industrial automation, factory floor devices |
| Network Topology | Line, star, tree | Line (trunkline with taps) |
| Data Speed | Up to 1 Mbps | Up to 500 kbps |
| Device Profiles | Extensive standardized profiles | Vendor-specific and some standard profiles |
| Object Dictionary | Mandatory, standardized | Not mandatory |
| Communication Types | PDO, SDO, NMT, SYNC | Explicit and implicit messaging |
| Network Size | Up to 127 nodes | Up to 64 nodes |
| Addressing | Node-ID (1-127) | MAC ID (0-63) |
| Configuration | Standardized via EDS files | Configured via LDF files |
| Licensing | Open, no license fees | Proprietary, license fees apply |
Introduction to CANopen and DeviceNet
CANopen and DeviceNet are two prominent communication protocols used in industrial automation for networked control systems. CANopen, built on the CAN (Controller Area Network) standard, provides a flexible, high-level protocol designed for embedded systems and supports real-time data exchange, device profiles, and extensive configuration options. DeviceNet, based on CAN technology as well, emphasizes ease of use and integration in industrial environments by offering standardized device profiles and simplified network management for sensor and actuator communication.
Overview of CAN Protocol in Industrial Automation
The CAN protocol serves as the foundation for both CANopen and DeviceNet, enabling robust communication in industrial automation systems. CANopen offers higher-layer protocols designed for device interoperability and flexible network management, while DeviceNet integrates CAN with a robust application layer tailored for industrial control devices. Understanding the protocol differences helps you select the most suitable network for real-time data exchange and system scalability in manufacturing environments.
Technical Architecture Comparison
CANopen employs a layered protocol architecture based on the OSI model, featuring a flexible communication profile with standardized device profiles and an object dictionary facilitating interoperability. DeviceNet uses a simplified application layer built on the CAN protocol incorporating predefined device profiles and a producer-consumer communication model optimized for real-time industrial automation. Both protocols leverage the CAN physical layer but differ in network management, with CANopen supporting dynamic configurations through Network Management (NMT) and DeviceNet relying on explicit messaging and implicit I/O messaging for device control and data exchange.
Communication Models and Data Handling
CANopen utilizes a master-slave communication model with a focus on standardized object dictionaries and predefined communication objects, allowing efficient peer-to-peer data exchange and cyclic or event-driven messaging. DeviceNet employs a producer-consumer model based on the CAN 2.0B specification, using connection-based messaging to prioritize real-time data transfer and support explicit and implicit data communication. Data handling in CANopen is structured around service data objects (SDOs) for configuration and process data objects (PDOs) for real-time data, whereas DeviceNet focuses on explicit messaging for non-time-critical information and implicit messaging for timed, cyclical data.
Network Topology and Scalability
CANopen supports flexible network topologies including star, line, and tree configurations, facilitating easy expansion with up to 127 devices per network segment. DeviceNet primarily uses a linear bus topology with trunk and drop lines, supporting up to 64 devices per network, which limits scalability in complex systems. The modular architecture of CANopen allows greater scalability and adaptability for industrial automation compared to the more rigid DeviceNet structure.
Device Compatibility and Interoperability
Device compatibility and interoperability between CANopen and DeviceNet differ significantly due to their protocol architectures. CANopen, based on the higher-layer CANopen protocol, offers extensive interoperability across devices from various manufacturers by adhering to standardized device profiles and object dictionaries. DeviceNet, built on the CIP (Common Industrial Protocol), ensures seamless device compatibility primarily within Rockwell Automation ecosystems, limiting interoperability outside its proprietary framework.
Configuration, Setup, and Maintenance
CANopen simplifies configuration and setup with standardized device profiles and tools that enable easy parameterization and network management, reducing commissioning time. DeviceNet requires more extensive initial configuration through vendor-specific software and detailed addressing, which can extend setup duration but allows tailored network control. Your maintenance efforts benefit from CANopen's robust diagnostics and modular device replacement, while DeviceNet offers comprehensive error reporting but demands deeper protocol knowledge for troubleshooting.
Performance, Speed, and Reliability
CANopen offers high reliability with real-time communication capabilities and deterministic data transfer, making it suitable for complex automation systems requiring precise control. DeviceNet provides robust performance at speeds up to 500 kbps with efficient peer-to-peer communication ideal for industrial applications with moderate data load. Your choice depends on whether you prioritize CANopen's flexibility and interoperability or DeviceNet's established reliability in harsh environments.
Industry Adoption and Application Areas
CANopen is widely adopted in industrial automation, medical equipment, and building automation due to its flexible device profiles and extensive support for real-time control applications. DeviceNet is primarily used in automotive manufacturing and factory automation, favored for its robustness in harsh environments and seamless integration with Rockwell Automation products. Both protocols ensure reliable communication on CAN buses but differ significantly in their industry-specific adoption and tooling ecosystems.
Future Trends and Evolution of CANopen and DeviceNet
CANopen is rapidly evolving with a focus on enhanced IoT integration, increased network scalability, and improved security features, making it well-suited for Industry 4.0 applications. DeviceNet is gradually being phased out in favor of newer protocols like Ethernet/IP, though it still maintains relevance in legacy systems due to robust device compatibility and established market presence. Your choice between CANopen and DeviceNet should consider long-term network expansion, support for modern automation standards, and future-proofing requirements.
CANopen vs DeviceNet Infographic
