What are safety relays?

Safety Relays are specialised devices used in industrial settings to monitor and control safety-related functions. They are crucial in applications where the failure of a safety component could result in hazardous situations, particularly  around moving machinery or high-risk manufacturing processes.

These relays guarantee a reliable response in case of error. They are engineered to prevent any loss of safety function caused by faults within the device itself or external faults from sensors of actuators. Safety relays can be activated through various methods, such as light curtains, which detect interruptions in a light beam to trigger safety functions like shutting down moving machinery.

How do safety relays work?

At their core, safety relays operate similarly to standard relays, serving as electrically operated switches. They consist of input and operating contact terminals and can be configured in various contact forms, including make contact, break contact, or a combination of both.

While modern technology has replaced relays in many applications with microchips and processors, relays remain valuable in industry due to their simplicity and reliability. They require minimal power to operate and are less prone to failures. Safety relays, despite their specific safety-oriented application, share the same basic construction and operation principles as regular relays.

Uses for safety relays

Safety relays find extensive use in safety circuits governed by standards like the European Machinery Directive 2006/42/EG. They are deployed for monitoring a range of safety functions, including:

• Monitoring of safety doors and flaps
• Interlocking devices
• Access monitoring
• Speed, standstill and position monitoring
• Emergency Stop functions and restart inhibitors
• Two-hand operating devices