Pepperl+Fuchs KFA5-SR2-Ex1.W.LB Switch Amplifier 115V AC

Pepperl+Fuchs KFA5-SR2-Ex1.W.LB Switch Amplifier

Product Introduction

The Pepperl+Fuchs KFA5-SR2-Ex1.W.LB switch amplifier functions as an isolated barrier for digital signals. It connects NAMUR sensors or dry contacts from hazardous areas to a safe-area control system. This 1-channel device runs on 115V AC power. Furthermore, it includes two relay outputs: one for the signal channel and another for fault indication. You can reverse its operating mode easily. Therefore the KFA5-SR2-Ex1.W.LB adapts to both normally open and normally closed input configurations.

Key Technical Specifications

Input type: NAMUR sensor (EN 60947-5-6) or dry contact.
Rated voltage: 103.5 ... 126 V AC, 45 ... 65 Hz.
Output: Relay contact output.
Fault output: Separate relay contact (fault relay).
Line fault detection (LFD): Yes, built-in.
Reversible mode of operation: Field-selectable.
Safety rating: Up to SIL2 per IEC 61508.

Explosion protection: Ex-Input (intrinsically safe input for hazardous area).

Input Specifications

The KFA5-SR2-Ex1.W.LB accepts two input signal types.

• NAMUR sensor: Compliant with EN 60947-5-6. Typical switching thresholds: <1.2 mA = off, >2.1 mA = on.

• Dry contact: Mechanical switch or relay contact.

Line fault detection monitors the field wiring. It detects short-circuit (current >6 mA) and wire break (current <0.1 mA). When a fault occurs, the fault relay changes state immediately.

Output Specifications

The main output is a relay contact. Its behavior follows the input state or reverses depending on your mode selection.
The fault relay output operates independently. It remains energized during normal operation. Upon a line fault or device internal error, this relay de-energizes. Use it to trigger an alarm or shutdown logic.

Safety and SIL2 Compliance

Engineers designed the Pepperl+Fuchs KFA5-SR2-Ex1.W.LB for functional safety applications. It meets SIL2 requirements according to IEC 61508. The device suits safety loops up to SIL2 when properly configured. For instance, you can use it in emergency shutdown systems or burner management.

Hazardous Area Approvals

Explosion protection type: Ex-input (intrinsically safe input circuit).
Connect NAMUR sensors or dry contacts located in Zone 0, Zone 1, or Zone 2. The safe-side output relays reside in the non-hazardous area.

Environmental and Mechanical Data

Ambient temperature range: -20 °C to 60 °C (-4 °F to 140 °F).
Degree of protection: IP20.
Mounting: 35 mm DIN rail per EN 60715.
Dimensions: Standard K-System housing (approx. 20 mm width).
Weight: 0.35 kg.

How to Install the KFA5-SR2-Ex1.W.LB

First, mount the device on a 35 mm DIN rail in a safe area or an enclosure rated for Zone 2. Then connect the 115V AC supply to the designated power terminals. Next, wire your NAMUR sensor or dry contact to the input terminals (Ex side).

For the output side, connect the signal relay to your PLC or DCS input. Additionally, wire the fault relay to an alarm monitoring channel. Then select the operating mode (energized on or de-energized on) using the internal jumpers or DIP switches as shown in the datasheet.

Finally, perform a line fault detection test. Simulate a wire break and a short circuit to verify the fault relay responds correctly.

Packaging List

• 1 x KFA5-SR2-Ex1.W.LB switch amplifier

• 1 x Terminal label set

• 1 x Installation instruction leaflet

Shipping Information

Carriers: FedEx, UPS, DHL.
All orders ship from our regional warehouse. Tracking number provided within 24 hours.

Frequently Asked Questions (FAQ)

1. Can the KFA5-SR2-Ex1.W.LB work with a 3-wire NAMUR sensor?
No. This model supports only 2-wire NAMUR sensors per EN 60947-5-6. For 3-wire sensors, consider other Pepperl+Fuchs models like the KFD2 series.

2. How do I reverse the output logic on this switch amplifier?
You change the operating mode using an internal jumper or DIP switch. Refer to the device label or manual. When reversed, an open input condition energizes the output relay.

3. What does line fault detection (LFD) actually monitor?
LFD monitors the field wiring between the KFA5-SR2-Ex1.W.LB and the NAMUR sensor. It detects wire break (current too low) and short circuit (current too high). Both conditions trigger the fault relay.

4. Is this device suitable for safety loops up to SIL3?
No. The maximum safety rating is SIL2 per IEC 61508. For SIL3 applications, you would need two devices in redundancy or a higher-rated barrier.

5. Can I supply 230V AC instead of 115V AC?
No. The Pepperl+Fuchs KFA5-SR2-Ex1.W.LB specifically requires 103.5–126V AC (115V nominal). Using 230V AC will permanently damage the unit. Choose the correct voltage variant for your system.