Euchner MGB-L2B-PNA-L-121853 Guard Locking Safety Switch
The Euchner MGB-L2B-PNA-L-121853 is a modular guard locking system with integrated evaluation electronics, designed for movable machine guards. It combines a safety interlock, guard locking, and diagnostic communication in one compact housing.
Mechanical Specifications
Housing material: glass-fiber reinforced thermoplastic (UL 94 V-0). Dimensions: 179 mm (H) × 40 mm (W) × 45 mm (D). Weight 0.4 kg. The locking principle is spring-loaded (magnetic unlocking), meaning the guard is locked when power is removed (fail-safe). Holding force: 1500 N (for locking bolt). Actuator type: RFID coded actuator (A‑C‑SST‑R or similar) with individual electronic code. The switch head can be repositioned in 8 directions (45° steps).
Electrical Data
Supply voltage: 24 VDC ±15% (SELV/PELV). Power consumption: 2.5 W maximum. Two safety outputs (OSSDs) provide 24 VDC, 0.5 A each, with redundant short-circuit protection. Auxiliary outputs: 2 PNP signals (guard locked and actuator present). Communication interface: Profinet (IRT) with integrated switch for daisy-chaining; supports I&M functions and device diagnostics via GSDML file. LED indicators show operating status, locking state, and network link activity.
Safety Ratings
Performance Level: PL e (EN ISO 13849-1), Category 4. SIL level: SIL 3 (EN 61508, EN 62061). Probability of dangerous failure per hour (PFHd): 3.5×10⁻⁹. Mission time: 20 years. The device continuously monitors for cross faults, actuator removal, and internal logic errors. The RFID actuator has a unique code stored in the switch’s memory; teach-in procedure locks the actuator to a specific switch, preventing substitution.
Installation and Environmental
Protection class: IP67 (housing) / IP69K (with optional sealing). Operating temperature: –20°C to +55°C. Connection is via an M12 8-pin (male) for Profinet and power; a second M12 4-pin (female) for network daisy chain. Mounting screws (M4) with washers; tightening torque 0.8 Nm. The switch must not be used as a mechanical stop; separate hard stops are required for the guard. Cable length between switch and actuator: unlimited but signal quality must be ensured for Profinet.
Configuration and Diagnostics
Parameter assignment via Profinet using the Euchner configuration tool or standard software (e.g., Siemens TIA Portal). Parameters include locking monitoring delay, auto‑reset after guard closing, and emergency unlock behavior. Diagnostics data includes actuator ID, locking force degradation, temperature warnings, and cycle counter (total operations). A web server accessible via IP address provides detailed status and statistics.
Applications
Typical for heavy-duty machine guards on presses, robotic cells, packaging machines, and conveyor systems where personnel access must be prevented while the machine is running. The MGB-L2B-PNA-L-121853 supports sequential locking where a second switch monitors the locked position. For emergency release (e.g., trapped person), an optional manual release mechanism is available as an accessory.
