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Machine Safety

Machine Safety

Light curtains, E-stops, safety relays, interlocks and guarding.

Also searched as: light curtaine stopsafety relayinterlock switchmachine guard

About machine safety

Machine safety components are critical for protecting personnel and equipment in industrial environments. This category includes light curtains (safety light screens), emergency stop (E-stop) devices, safety relays, interlock switches, and machine guarding. Light curtains, typically Type 2 or Type 4 per IEC 61496, create a protective field using an emitter and receiver, with resolution (e.g., 14mm for finger protection, 30mm for hand protection) and protected height being key specifications. E-stops are push-button or pull-cord devices designed for immediate machine shutdown, often featuring twist-to-release or key-release mechanisms, and contact configurations like 1NC/1NO or 2NC. Safety relays (e.g., PLe, SIL 3 rated) monitor safety functions and provide redundant outputs, with common types including emergency stop relays, guard interlock relays, and two-hand control relays. Interlock switches prevent machine operation when guards are open, available in mechanical (tongue/key), magnetic, and RFID-coded variants, with locking force (e.g., 1300N, 2500N) and IP rating (e.g., IP67) being important. Machine guarding encompasses physical barriers such as wire mesh panels, polycarbonate sheets, and aluminum profiles, selected based on impact resistance, visibility requirements, and mounting options.

How to choose

When selecting machine safety components, first determine the required Performance Level (PL) per ISO 13849-1 or Safety Integrity Level (SIL) per IEC 62061 for the application. Next, identify the specific hazard and the necessary protective function (e.g., presence detection, emergency stop, guard interlocking). For presence detection, choose a light curtain based on resolution (finger, hand, body) and protected height. For E-stops, select based on actuation method (push-button, pull-cord) and contact configuration. For interlocks, consider the guard type, locking requirement, and actuator type (tongue, RFID). Finally, select a safety relay or safety PLC capable of achieving the required PL/SIL, ensuring compatibility with all connected safety devices and monitoring functions.