CANopen Safety Protocol

What Is CANopen Safety?

CANopen Safety (defined in EN 50325-5) is a safety extension to CANopen that enables safety-related communication between devices (such as sensors, controllers, and drives) on a CAN network.

It adds safety mechanisms that help a system:

• Detect errors and data corruption
• Identify missing, delayed, or repeated messages
• Maintain safe behavior during faults or communication issues

In short: CANopen Safety helps safety systems trust the data they receive—and react appropriately when they can’t.

Why CANopen Safety Matters in Functional Safety

Functional safety is about reducing risk when things go wrong: component failures, wiring issues, noisy environments, unexpected behavior, or communication faults.

CANopen Safety supports functional safety designs by helping ensure:

• The right device is communicating
• The message is complete and unaltered
• The message arrives within expected timing
• Faults are detected and handled predictably

This is especially important for safety functions that rely on accurate motion data, such as safe speed monitoring or safe position monitoring.

CANopen vs CANopen Safety

This separation helps support safety architectures where safety data must be validated and monitored continuously.

Where CANopen Safety Is Commonly Used

CANopen Safety is a strong fit anywhere CAN networks are already established and reliability is critical, including:

• Mobile equipment (construction, agriculture, utility vehicles)
• Material handling (conveyance, lifting, automated transport)
• Industrial automation (packaging, processing, assembly)
• Harsh environments with vibration, dust, temperature swings, and electrical noise
  

CANopen Safety and Motion Feedback

Motion feedback devices—like encoders—are often key inputs in safety systems. They can support safety-related functions by providing motion data used to evaluate system state (for example: speed, direction, position, or movement presence).

When motion feedback is integrated into a CANopen Safety architecture, it supports a system approach where:

• Motion data can be monitored as safety-relevant information
• Communication faults can be detected faster
• Safety controllers can respond predictably to invalid or missing data

Note: Supported safety functions, architecture options, and certifications depend on the final device design and system implementation.

Planning for CANopen Safety

If CANopen Safety is on your roadmap, early planning helps avoid redesign later. Helpful questions to evaluate now:

• What safety functions will the system require (safe speed, safe position, safe stop, etc.)?
• What safety controller or safety PLC will be used?
• What is the target safety level and compliance requirement?
• What environment will devices face (shock, vibration, moisture, washdown, EMI)?
• What diagnostics and fault responses are required?

CANopen Safety FAQ

EPC's CANOpen Safety Encoders