Profinet to CANopen Gateway Links Siemens PLC to Magnetic Track

Why Protocol Conversion Matters in Automation

Industrial environments often mix equipment from various manufacturers, each using different fieldbus or industrial Ethernet protocols. Profinet is widely adopted in Siemens PLC-based systems, while CANopen is prevalent in motion control devices like magnetic tracks, servo drives, and encoders. Without a gateway, these systems cannot communicate directly, leading to isolated data silos and reduced efficiency. A Profinet to CANopen gateway acts as a bridge, translating data between the two networks in real time, ensuring seamless integration and centralized control.

System Components and Setup Overview

The configuration involves three main components:

• Siemens SIMATIC S7-1200 PLC – acts as the Profinet IO controller, managing logic and data exchange.
• Profinet to CANopen gateway – a device that converts Profinet data to CANopen frames and vice versa. It typically features one Profinet port and one or two CANopen ports.
• Magnetic track system – a linear or planar motor system used for high-precision positioning, often controlled via CANopen drives.

The gateway is configured using two software tools: the Siemens TIA Portal for Profinet setup and a dedicated CANopen configuration tool provided by the gateway manufacturer.

Step-by-Step Configuration Process

1. Installing the GSD File in TIA Portal

The gateway vendor provides a GSD (General Station Description) file that describes the device’s Profinet capabilities. In TIA Portal, you install this file via the “Options” > “Manage general station description files (GSD)” menu. Once installed, the gateway appears in the hardware catalog under “Other field devices” > “PROFINET IO” > “Gateway”.

2. Adding the Gateway to the PLC Project

Drag the gateway from the catalog to the network view and connect it to the PLC’s Profinet port. Assign a unique device name and IP address that matches the settings you will later configure in the CANopen tool. In the device properties, add the required I/O modules (input/output bytes) based on the data size needed for the magnetic track control. Typical configurations use 8, 16, or 32 bytes of cyclic data.

3. Configuring CANopen Parameters

Launch the gateway’s CANopen configuration software. Set the master parameters:

• Baud rate: must match the magnetic track drive’s setting (common rates: 125 kbps, 250 kbps, 500 kbps, 1 Mbps).
• Communication cycle period: change from default 0x00000000 to 0x0000FFFF to enable cyclic data exchange.
• Node ID: assign a unique CANopen node ID to the gateway (usually 1..127).

4. Mapping PDOs for Data Exchange

Process Data Objects (PDOs) carry real-time control and status data. In the CANopen tool, add the required RPDOs (receive) and TPDOs (transmit) that correspond to the magnetic track’s control words, target positions, actual positions, and status words. Set the transmission type to “event-driven” (manufacturer-specific) to optimize bus load. Map each PDO to the gateway’s I/O bytes that were defined in TIA Portal.

5. Downloading Configuration to the Gateway

Ensure your PC is on the same subnet as the gateway’s default IP (often 192.168.0.x). Use the configuration software to search for the device and download the settings. A success message confirms the download. After this, the gateway will automatically start data exchange when the PLC is in RUN mode.

Monitoring and Control via PLC

Once the gateway is operational, the PLC can read and write data to the magnetic track through the mapped I/O areas. For example, to move the track to a target position, the PLC writes the position value to the corresponding output bytes. The actual position feedback is read from input bytes. Diagnostic information, such as communication errors or drive faults, can also be monitored in the PLC program.

Benefits of Using a Profinet to CANopen Gateway

Common Pitfalls and Troubleshooting Tips

• Baud rate mismatch: Double-check that the CANopen baud rate in the gateway matches the drive’s setting. A mismatch will cause no communication or intermittent errors.
• IP address conflicts: Ensure the gateway’s IP is unique on the Profinet network and not used by other devices.
• PDO mapping errors: Verify that the number of bytes mapped in the gateway equals the I/O module size in TIA Portal. Mismatched lengths lead to data corruption.
• Network segmentation: The PC used for configuration must be in the same IP subnet as the gateway’s default IP; otherwise, the software cannot discover the device.
• Firmware compatibility: Keep the gateway firmware updated to ensure compatibility with the latest PLC and drive firmware versions.

Real-World Application Example

In a packaging machine, a magnetic track transports products between stations. The Siemens S7-1200 PLC controls the entire machine sequence, while the magnetic track’s servo drives communicate via CANopen. By installing a Profinet to CANopen gateway, the PLC directly commands the track’s position and speed, synchronizing it with other actuators like grippers and labelers. This integration reduced wiring complexity and improved cycle time by 15% compared to a previous discrete I/O solution.

Conclusion

The Profinet to CANopen gateway is a proven, cost-effective method to bridge Siemens PLCs with CANopen-based motion systems like magnetic tracks. Following the configuration steps outlined above ensures a stable connection, enabling advanced automation functions and improving overall equipment effectiveness. As industrial IoT and smart manufacturing evolve, such protocol converters will remain essential for integrating diverse devices into unified control architectures.