What is DeviceNet?
DeviceNet is an industrial communication protocol based on the CAN bus protocol (Controller Area Network). It is used to connect field equipment such as Sensors, Actuators, motors and I/O modules to control systems such as PLCs.
DeviceNet was developed by Allen-Bradley/Rockwell Automation and is managed by ODVA (Open DeviceNet Vendors Association).
🧠 What does DeviceNet do?
DeviceNet enables you to:
- Connect multiple devices via a single cable (bus structure)
- Exchange data between devices in real time
- Combine power and communication on the same cable (4-wire)
- Detect and configure devices automatically through plug-and-play
🔧 Key features of DeviceNet
| Feature | Description |
|---|---|
| Based on CAN | Uses CAN at the lower layers, with additional definitions on top |
| Multimaster capable | Supports multiple controllers on the same bus |
| Topology | Linear bus with T-junctions permitted |
| Power + data | Power (24 V DC) and communication on the same cable |
| Data transport | Supports both I/O messaging and explicit messaging |
| Baud rates | 125, 250 or 500 kbit/s (depending on cable length) |
🏭 Example applications
- Packaging machines: communication with motors, Sensors and valves
- Conveyor systems: I/O control of conveyors
- Automotive production lines
- Panel building: simple connection of field components
- Modular machines: easy expansion through plug-and-play
🔄 DeviceNet vs. other fieldbuses
| Aspect | DeviceNet | Profibus-DP | Modbus RTU |
|---|---|---|---|
| Physical layer | CAN bus | RS-485 | RS-485 |
| Baud rate | Up to 500 kbit/s | Up to 12 Mbit/s | Up to 115 kbit/s |
| Power on bus | Yes | No | No |
| Plug-and-play | Yes | No | No |
| Real-time behaviour | Good | Excellent | Limited |
| Popularity | Mainly in Rockwell/Allen-Bradley | Mainly in Siemens/Europe | Widely used |
🔐 Limitations of DeviceNet
- Limited cable length at higher speeds (e.g. max. 100 m at 500 kbit/s)
- Outdated compared with Ethernet-based alternatives such as Ethernet IP
- Protocol-specific (less universal than OPC UA or ProfiNET)
📌 In summary
DeviceNet is a CAN-based industrial network protocol that provides simple and reliable communication between control systems and field devices, particularly in machinery and factory automation.