The KFD2‑SR2‑Ex2.2S from PEPPERL+FUCHS is a dual-channel intrinsically safe switch amplifier and isolation barrier. It is designed for isolated transmission of digital signals between hazardous areas (Zone 0/1/2) and safe areas. The device accepts inputs from NAMUR sensors or dry contacts, and features two independent relay outputs with AND logic. Equipped with Line Fault Detection (LFD) and reversible output status, it complies with SIL 2 functional safety requirements. This product is widely applied in explosion-proof industrial fields such as chemical, petroleum and natural gas industries.
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PEPPERL FUCHS KFD2-SR2-EX2.2S Switch Amplifier.pdf
Core Functions & Features
Dual-channel Isolation & Signal Transmission: Equipped with two independent inputs to receive NAMUR (EN 60947‑5‑6) or dry contact signals, realizing reliable isolated transmission of digital signals from hazardous areas to safe areas.
Relay Output with AND Logic: Each channel provides 2 Type A normally open relay contacts, forming 2×2 relay outputs that support AND logic operation. Contact rating: 50 V AC/1 A (cosφ>0.7) or 40 V DC/1 A (resistive load).
Line Fault Detection (LFD): Enabled or disabled via DIP switch S3. It detects open circuits (I≤0.1 mA) and short circuits (I>6 mA). In the event of a fault, the relays de-energize and the LED indicators comply with NAMUR NE44 standards.
Reversible Operation Mode: DIP switches S1/S2 switch the output logic of Channel 1 and Channel 2 respectively, reversing the relay actuation status under high or low input current.
Functional Safety & Explosion Protection: Compliant with IEC 61508 SIL 2. Certified to ATEX/IECEx (II (1) GD [EEx ia] IIC, II 3G Ex nA nC IIC T4), suitable for Zone 0/1/2 hazardous areas.
Power Supply & Mounting: Rated 24 V DC (operating range: 20–30 V DC). Powered via Power Rail or terminals 14+/15-. Designed for DIN rail mounting with IP20 protection degree and operating temperature range of -20 ~ 60°C.
Technical Specifications
Input: NAMUR / Dry contact; Open-circuit voltage ≈8 V DC, Short-circuit current ≈8 mA; Switching point: 1.2–2.1 mA, Hysteresis ≈0.2 mA.
Output: 2×2 relays; Mechanical service life: 10⁸ operations; Operate/reset delay ≈20 ms; Maximum switching frequency: ≤10 Hz.
Electrical Isolation: Reinforced insulation (375 V peak) between input & output, input & power supply; Basic insulation between output and power supply.
Power Consumption: ≤1.3 W; Operating current: ≤50 mA.
Dimensions & Weight: 20 mm (W) × 119 mm × 115 mm; Approx. 150 g.
Panel & Wiring
Panel Indicators: Green LED (Power), Yellow LED (Relay status), Red LED (Line fault). DIP switches: S1 (Channel 1 mode), S2 (Channel 2 mode), S3 (LFD enable/disable).
Terminals:
- Input: Channel 1 (1+/2+/3-), Channel 2 (4+/5+/6-)
- Output: Channel 1 (7/8/9), Channel 2 (10/11/12)
- Power: 14+ (24 V DC), 15- (GND)
Configuration & Fault Diagnosis
Factory Default Settings: S1/S2/S3 all set to Position I (relay actuates at high current, LFD enabled).
Fault Response: Relays de-energize and red LED lights up upon line faults. Collective fault alarm is supported via Power Rail.
Certifications & Compliance
- Explosion Protection: ATEX PTB 00 ATEX 2083, IECEx TUN 19.0013X
- Functional Safety: IEC 61508 SIL 2
- EMC: EN 61326‑1, EN 50178
Application Scenarios
- Isolation and conversion of signals from NAMUR proximity switches, limit switches and dry contacts in Zone 0/1/2 hazardous areas.
- Relay outputs in safe areas for driving solenoid valves, indicator lights, alarm circuits, etc.
- Safety interlock circuits requiring SIL 2 rating, such as emergency shutdown and flame detection systems.
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