Safety Relays

A safety relay is an automation device that monitors for potential errors or faults in machinery or plants and works to prevent injury and reduce risk. If an error occurs, the safety relay initiates the appropriate response to reduce the risk and bring the environment back to a safe, acceptable level. Monitoring processes using safety relays protects both the machinery and the employees, prevents potentially expensive maintenance and equipment replacement, and reduces risk of human injury.

Example functions include initiating a controlled pause in machinery or equipment to safely stop movement until an obstacle is removed. They can also be used as an emergency stop mechanism, switching off the power to particular machinery or plants until it is safe to resume power and continue.

Types of Safety Relay

• Single-Function Safety Relays – Monitor one specific function, such as emergency stop or guard monitoring.
• Multi-Function Safety Relays – Capable of monitoring multiple functions, reducing wiring and saving panel space.
• Dual-Channel Relays – Provide redundancy for critical safety circuits, ensuring compliance with safety standards.
• Latching Relays – Maintain their state until manually reset, ideal for emergency stop applications. Time-Delay Relays – Allow controlled shutdown or restart after a set time interval.
• Category 4 Safety Relays – Designed for high-risk applications requiring maximum fault tolerance.
• Emergency Stop Relays – Dedicated to monitoring and controlling emergency stop circuits.

Safety Relay Applications

• Two-hand control systems
• Movable guards and interlocks
• Light curtains, barriers, and grids
• Magnetic safety switches
• Safety mats and pressure-sensitive mats
• Three-position enabling devices
• Non-contact safety sensors
• Emergency stop buttons
• Robotics and automated machinery
• Packaging and material handling equipment

At RS, we stock a wide selection of safety relays from leading brands including Pilz, Phoenix Contact, Guardmaster, and Schneider Electric. To learn more about relays and their applications, take a look at our expert-reviewed Relays Guide.