Pepperl+Fuchs KFD2-SR2-EX2.W Safety Barrier: Technical Overview and Applications​

The Pepperl+Fuchs KFD2-SR2-EX2.W is a safety barrier module designed for signal isolation and energy limitation in hazardous industrial environments. It ensures safe signal transmission between equipment in explosive areas (e.g., chemical plants) and control systems in non-hazardous zones by restricting electrical energy to prevent ignition sources. Compact and DIN-rail mounted, it supports applications in process automation, safety interlocks, and emergency shutdown systems .

​Technical Specifications and Functional Design​

The module operates on a standard 20–30V DC supply voltage and provides galvanic isolation (≥1500V AC) between input, output, and power circuits. It accepts analog signals (e.g., 4–20mA, 0–10V) or digital signals from field devices like pressure transmitters or temperature sensors, delivering isolated outputs to PLCs/DCS. Key parameters include a response time ≤100ms, dual-channel capability, and compliance with ATEX/IECEx certifications for Zone 1/21 or Zone 2/22 hazardous areas. The "SR2" designation indicates safety relay functionality, while "EX2.W" denotes explosion-proof standards and a wide operating temperature range (-20°C to +60°C) .

​Safety Mechanisms and Certifications​

As an intrinsic safety (IS) barrier, the KFD2-SR2-EX2.W limits voltage (Ui ≤ 30V) and current (Ii ≤ 100mA) to hazardous-area devices, preventing spark-induced explosions. It carries international certifications (ATEX, IECEx) and features IP20 protection for cabinet installations. The module also supports HART communication for smart device diagnostics and includes LED indicators for fault detection, ensuring reliability in critical safety systems .

​Industrial Applications and Integration​

Widely used in oil/gas, chemical, and pharmaceutical industries, the barrier interfaces with sensors in explosive atmospheres (e.g., level transmitters in tanks) and control rooms. Its DIN-rail design simplifies integration into existing automation racks, while spring-clamp terminals enable quick wiring. By isolating ground loops and suppressing noise, it maintains signal accuracy in long-distance transmissions, reducing downtime in safety-instrumented systems (SIS) .

​Advantages Over Conventional Isolators​

Unlike basic zener barriers, the KFD2-SR2-EX2.W offers full galvanic isolation, eliminating the need for dedicated ground grids and supporting grounded field devices without signal distortion. Its dual-channel design consolidates functions in high-density panels, while compliance with SIL 2/3 standards makes it suitable for functional safety applications. These features underscore Pepperl+Fuchs’ expertise in robust industrial safety solutions .