Leuze MSI‑SR4B‑02 | Safety Relay | Emergency Stop & Safety Monitoring | Part No. 547951 Overview The Leuze MSI‑SR4B‑02 (part no. 547951) is a compact safety relay designed to monitor emergency stop functions, safety sensors, and contactor feedback circuits. With 3 redundant NO relay outputs and configurable restart logic, this relay meets stringent safety standards including SIL 3 and PL e, making it suitable for high-risk industrial applications. Key Features Safety Level: SIL 3 (IEC 61508), PL e (ISO 13849‑1), Cat. 4 Relay Outputs: 3 normally open (NO), redundant Restart Modes: Manual and automatic selectable Terminals: Spring-cage connection, 16-pin Supply Voltage: 24 V DC/AC ±20% LED Indicators: Supply, K1, K2, Reset Mounting: DIN rail, compact 22.5 mm housing Cross-circuit and contactor monitoring included Technical Specifications Specification Value Part Number 547951 Voltage Range 24 V DC/AC ±20% Current Consumption Max 100 mA Safety Outputs 3 NO relay outputs, 3 A (each) Max Thermal Current 6 A Restart Delay Manual: ~30 ms / Auto: ~300 ms Response Time Typical 10 ms Terminal Type Spring-cage, 0.2–1.5 mm² (AWG 24–16) Dimensions 22.5 × 111 × 114 mm Weight Approx. 170 g Protection Rating IP20 (terminals) / IP40 (housing) Operating Temperature 0 °C to +55 °C Storage Temperature –25 °C to +70 °C Mounting Type DIN rail (EN 60715) Standards IEC 61508, ISO 13849‑1, IEC/EN 62061 Applications Emergency stop circuits on industrial machines Safety light curtains and position sensors Transponder-based safety devices Contactor and feedback circuit monitoring SIL 3 / PL e compliant safety architectures Why Choose MSI‑SR4B‑02 Meets the highest international safety classifications Flexible restart configurations for custom safety logic Compact footprint ideal for control panel integration Tool-free spring terminals for fast, secure wiring Diagnostic LEDs aid real-time troubleshooting Order Now The Leuze MSI‑SR4B‑02 safety relay (part no. 547951) is available and ships worldwide for fast integration into your safety systems.
