Pepperl+Fuchs KFD2-SR2-Ex2 isolated barrier

The Pepperl+Fuchs KFD2-SR2-Ex2 is a high-performance, galvanically isolated barrier designed for intrinsically safe (IS) applications, providing robust signal conditioning and protection for two-channel 4–20 mA analog signals in hazardous areas (Zone 1/21, Zone 2/22). Unlike Zener barriers, it offers active isolation without requiring a ground connection for safety, making it ideal for complex or noisy environments.

Key Features of the KFD2-SR2-Ex2

✔ Dual-Channel Isolation – Protects two independent 4–20 mA loops.

✔ Galvanic Isolation – 500V AC isolation between channels/supply (no ground dependency).

✔ Intrinsic Safety Certifications:

ATEX / IECEx (Ex ia IIC T6 Ga / Ex ib IIC T6 Gb)

FM / CSA (Class I, II, III, Div. 1)

✔ Wide Power Supply Range: 20–253V AC/DC or 18–30V DC (selectable).

✔ Advanced Diagnostics:

LED per channel (green = OK, red = fault).

Short-circuit/open-circuit detection.

✔ Configurable Options:

Signal inversion (e.g., 4–20 mA to 20–4 mA).

Current limiting (adjustable).

Typical Applications

Process automation (pressure/flow/temperature transmitters in Ex zones).

Oil & gas refineries (redundant signal paths).

Pharmaceutical/Chemical plants (noise-sensitive environments).

Power generation (turbine monitoring).

Wiring & Installation

Power Supply Options

Terminals A1/A2: 20–253V AC/DC or 18–30V DC (jumper-selectable).

Channel Wiring (Per Channel)

Input (Field Side – Hazardous Area):

+ (IS+): Intrinsically safe input from transmitter.

– (IS–): Return line.

Output (Control Side – Safe Area):

+ (OUT+): 4–20 mA to PLC/DCS.

– (OUT–): Signal return.

⚠ Key Advantage vs. Zener Barriers:

No ground connection required for intrinsic safety (simplifies installation).

Comparison with Similar Barriers

Model Type Channels Key Difference

KFD2-SR2-Ex2 Galvanic Isolator 2 No ground, wide power range

Z786 Zener Barrier 1 Ground-dependent, lower cost

KFD2-STC4-Ex2 Temperature Converter 2 For thermocouples/RTDs

Why Choose the KFD2-SR2-Ex2?

✅ Eliminates ground-loop issues (critical in large plants).

✅ Flexible power supply (AC/DC or low-voltage DC).

✅ Dual-channel redundancy for critical processes.