The difference between DeviceNet and PROFINET

In the world of industrial automation, efficient and reliable communication between devices is crucial.
Two major communication protocols often discussed are DeviceNet and PROFINET.
While both serve the purpose of connecting industrial control systems, they have distinct characteristics and advantages.
Understanding these differences is essential for choosing the right protocol for your specific application.

What is DeviceNet?

DeviceNet is a communication protocol developed by Allen-Bradley, now part of Rockwell Automation.
It is based on the Controller Area Network (CAN) technology and is primarily used for device-level communication in industrial environments.

Key Features of DeviceNet

DeviceNet is known for its robustness and reliability.
It operates on a peer-to-peer network architecture, allowing devices to communicate directly with each other without the need for a central controller.

DeviceNet supports cyclic and event-driven communication, making it flexible for various industrial applications.
This protocol also provides power to devices through the same network cable, simplifying installation and reducing wiring costs.

DeviceNet operates at a range of data rates, providing flexibility in terms of speed and distance.
It’s particularly useful in environments where devices are spread over a relatively small area but require consistent communication.

What is PROFINET?

PROFINET is an industrial Ethernet protocol developed by PROFIBUS & PROFINET International (PI).
It is designed for high-speed, high-bandwidth communication and integrates seamlessly with existing Ethernet networks.

Key Features of PROFINET

PROFINET offers fast data exchange, supporting real-time and isochronous real-time communication.
This makes it suitable for applications requiring high precision and synchronization, such as motion control.

PROFINET is highly scalable, supporting a wide range of applications from simple IO devices to complex motion control and safety systems.
It can handle a large number of devices and provides extensive diagnostic and maintenance capabilities.

The protocol supports both cyclic and acyclic communication, ensuring timely data transfer while allowing for non-periodic information exchanges.
With its use of standard Ethernet, PROFINET allows for seamless integration with existing IT infrastructure, providing a pathway for convergence between industrial and office networks.

Comparing DeviceNet and PROFINET

While both DeviceNet and PROFINET are industrial communication protocols, their differences lie in the technology they are based on and their specific applications.

Communication Speed and Bandwidth

One of the most significant differences is in communication speed and bandwidth.
DeviceNet operates at slower speeds, typically up to 500 Kbps, making it suitable for applications with lower data transfer requirements.
On the other hand, PROFINET can operate at speeds up to 100 Mbps, providing higher bandwidth for applications requiring rapid and large amounts of data transmission.

Network Architecture

DeviceNet utilizes a simple peer-to-peer network structure, making it easy to implement in smaller systems where devices need to communicate directly with each other.
In contrast, PROFINET uses a more complex Ethernet-based architecture, allowing for more extensive and scalable network configurations.
This makes PROFINET ideal for large systems with numerous interconnected devices.

Power Supply

One of DeviceNet’s advantages is its ability to supply power to devices through the same network cable used for data transmission.
This reduces wiring complexity and costs.
PROFINET, however, does not provide power through the network cable, requiring separate power supply arrangements for connected devices.

Real-Time Capabilities

When it comes to real-time capabilities, PROFINET has a clear edge.
Its support for isochronous real-time communication enables high precision and synchronization, essential for applications such as motion control.
DeviceNet, while reliable, does not match the real-time performance levels offered by PROFINET.

Compatibility and Integration

DeviceNet is generally used in systems designed around Allen-Bradley/Rockwell Automation products, leading to better integration in environments dominated by these brands.
PROFINET, with its Ethernet foundation, offers broader compatibility and integration potential with existing IT infrastructure.
This makes it a more versatile choice for companies looking to integrate their industrial systems with enterprise networks.

Choosing the Right Protocol

Selecting between DeviceNet and PROFINET depends on your specific application requirements and existing infrastructure.

Considerations for DeviceNet

DeviceNet is an excellent choice for small to medium-sized systems that require robust and reliable communication.
Its ability to supply power through the network cable makes it cost-effective for installations with numerous devices.
It is particularly suitable for environments where devices need direct peer-to-peer communication without the expense of a central control unit.

Considerations for PROFINET

PROFINET excels in environments where high-speed, high-bandwidth communication is critical.
It is ideal for large-scale systems with extensive diagnostic and maintenance needs.
If your application involves synchronized motion control or requires seamless integration with existing IT networks, PROFINET is a more appropriate choice.

Conclusion

Both DeviceNet and PROFINET serve essential roles in industrial automation, each with unique strengths and applications.
DeviceNet is known for its robustness and simplicity, making it suitable for smaller, device-level networks.
PROFINET, with its high-speed and extensive capabilities, is better suited for complex and large-scale systems.
Understanding the specific needs of your application will guide you in choosing the right protocol, ensuring efficient and reliable communication within your industrial environment.