Pepperl+Fuchs KFD2-SR2-Ex2.W K-System Isolated Switch Amplifier
Overview
The Pepperl+Fuchs KFD2-SR2-Ex2.W is a 2-channel galvanically isolated switch amplifier from Pepperl+Fuchs’ DIN-rail K-System, built to safely bring NAMUR proximity switch or dry contact signals out of a hazardous area and present them to standard PLC or DCS relay inputs in the safe area. As part of the widely deployed K-System intrinsic safety barrier range, the KFD2-SR2-Ex2.W provides SIL 2 functional safety capability alongside ATEX, IECEx, and FM/UL certification, making it a standard building block wherever field-mounted NAMUR sensors on valves, agitators, or level switches must interface safely with control system logic.
As a supplier of Pepperl+Fuchs products, Seven Star LLC supplies the KFD2-SR2-Ex2.W isolated switch amplifier to instrumentation and E&I engineering teams across Oman, Muscat, and the wider GCC, with application selection support and spares quoted on request.
Operating Principle
The KFD2-SR2-Ex2.W monitors each of its two input channels for a NAMUR-standard switching current (nominally 1.2–2.1 mA on, roughly 0.2 mA off) or a simple dry contact closure from a field device located in a classified hazardous area, and limits the energy delivered to that circuit to a level incapable of igniting a flammable atmosphere – this is the fundamental function of an intrinsically safe isolated barrier. Internally, the detected switch state is optically or transformer-isolated from the field circuit and converted into a Form-C relay contact output in the safe area, fully decoupling the hazardous-area wiring from the control system’s own power and ground reference.
This galvanic isolation also provides line fault detection, allowing the module to distinguish a genuine switch operation from an open or short circuit in the field wiring, and to report that fault condition independently to the control system. Because the barrier both enforces intrinsic safety limits and cleanly isolates the two electrical domains, it eliminates ground loop and noise coupling issues that would otherwise arise from connecting hazardous-area field wiring directly into a PLC or DCS input card.
Engineering Design of the Pepperl+Fuchs KFD2-SR2-Ex2.W
The KFD2-SR2-Ex2.W is housed in a compact 20 mm wide K-System housing (type B2, 20 x 119 x 115 mm W x H x D) designed for 35 mm DIN rail mounting per EN 60715, allowing dense packing of multiple channels within a standard marshalling cabinet. The module is powered from a 19–30 VDC supply at ≤50 mA, and provides Form-C relay contact outputs rated at 250 VAC/2 A, 126.5 VAC/4 A, or 40 VDC/2 A resistive, giving direct compatibility with a wide range of PLC and DCS digital input modules and annunciator panels.
Certification coverage includes ATEX (Ex ia Ga IIC / Ex ia Da IIIC / Ex ia Ma I, PTB 00 ATEX 2080) and IECEx (PTB 11.0034, TUN 19.0013X) for the intrinsically safe field circuit, plus FM and cULus approvals for North American installations, alongside SIL 2 / SC 3 functional safety certification per IEC/EN 61508 for use in safety instrumented functions. Front-panel LED indicators and DIP switches allow local diagnosis and reconfiguration of channel mode (NAMUR or dry contact, energized or de-energized relay logic) without removing the module from its DIN rail terminal base.
Key Features
The Pepperl+Fuchs KFD2-SR2-Ex2.W combines proven K-System reliability with the certifications and diagnostics modern safety-instrumented systems demand. Key features include:
- 2-channel isolated barrier accepting NAMUR proximity switch or dry contact inputs from a classified hazardous area.
- Form-C relay contact outputs rated up to 250 VAC/2 A for direct PLC/DCS or annunciator compatibility.
- ATEX and IECEx certified for Ex ia Ga IIC / Ex ia Da IIIC / Ex ia Ma I hazardous area classifications.
- SIL 2 (SC 3) functional safety certification per IEC/EN 61508 for safety instrumented functions.
- Line fault detection distinguishes genuine switch operation from open or short field wiring faults.
- Reversible relay logic (energized or de-energized on switch actuation) configurable via front DIP switches.
- Compact 20 mm K-System housing for high channel density on standard 35 mm DIN rail.
- FM and cULus approvals in addition to ATEX/IECEx, supporting both European and North American installations.
Industrial Applications
The Pepperl+Fuchs KFD2-SR2-Ex2.W is deployed throughout Oman’s oil and gas, petrochemical, and process industries wherever NAMUR proximity switches monitor valve position, agitator or pump status, or level and proximity detection in classified Zone 0/1/2 areas, including tank farms, offshore platforms, and refinery process units across the Sohar and Salalah economic zones. Its SIL 2 rating also makes it a common choice for safety instrumented system (SIS) field interfaces where a certified, auditable isolation barrier is required between a hazardous-area limit switch and the safety PLC.
As the trusted supplier for Pepperl+Fuchs, Seven Star LLC supplies the KFD2-SR2-Ex2.W to instrumentation contractors, EPC firms, and plant E&I maintenance teams across Oman and the GCC, supplying genuine barriers configured to the correct channel mode and relay logic for each hazardous-area interface.
Technical Specifications
The table below summarizes the principal Pepperl+Fuchs KFD2-SR2-Ex2.W specifications for this isolated switch amplifier, useful when specifying a KFD2-SR2-Ex2.W for a hazardous-area interface.
| Parameter | Specification |
|---|---|
| Model | Pepperl+Fuchs KFD2-SR2-Ex2.W |
| Product family | K-System DIN-rail intrinsic safety isolated barrier |
| Channels | 2, NAMUR proximity switch or dry contact input |
| Switching threshold | ≈1.2–2.1 mA on / ≈0.2 mA off (NAMUR) |
| Output | Form-C relay contacts, 250 VAC/2 A, 126.5 VAC/4 A, or 40 VDC/2 A resistive |
| Supply voltage | 19–30 VDC, ≤50 mA |
| Hazardous area certification | ATEX Ex ia Ga IIC / Ex ia Da IIIC / Ex ia Ma I; IECEx PTB 11.0034 |
| Functional safety | SIL 2, SC 3 per IEC/EN 61508 |
| Additional approvals | FM, cULus |
| Housing / mounting | 20 x 119 x 115 mm (W x H x D), 35 mm DIN rail (EN 60715) |
Request a Quote for Pepperl+Fuchs KFD2-SR2-Ex2.W
Seven Star LLC invites instrumentation engineers, EPC contractors, and plant maintenance teams across Oman and the GCC to submit a formal RFQ for the Pepperl+Fuchs KFD2-SR2-Ex2.W isolated switch amplifier. We supply on request with lead time confirmed at quotation, can supply the full manufacturer technical datasheet on request, and our instrumentation division is available to help confirm the correct channel configuration and certification for your hazardous-area application. In Oman and the GCC, Seven Star LLC provides manufacturer documentation and dependable local technical support for every KFD2-SR2-Ex2.W supplied.
Browse the full Pepperl+Fuchs range or see more Isolator & Barrier products supplied by Seven Star LLC in Oman and the GCC.
- datasheet Pepperl+Fuchs KFD2-SR2-Ex2.W Datasheet Download
Pepperl+Fuchs product families on this page
On the interface side there are two systems. The K-System mounts on DIN rail and is represented here by the KFD2-UT2-Ex2 universal temperature converter. The H-System plugs into termination boards and is represented by the HiD2030 SMART transmitter power supply with HART. The PS1000-A6-24.20 is a 24 VDC, 20 A power supply for cabinets. Sensors listed include the NJ2-12GK-SN NAMUR inductive sensor, the R101 retro-reflective photoelectric sensor and the R2000 2-D LiDAR scanner. For field staff there are the Tab-Ex 05 DZ1 tablet for Zone 1/21 areas and the Smart-Ex 03 DZ2 smartphone for Zone 2/22 and Division 2 areas.Where Pepperl+Fuchs equipment is used
Isolated barriers sit between field instruments in Zone 0 or Zone 1 and the DCS or safety system in refineries, gas plants and chemical works. NAMUR sensors report valve position and machine states in classified areas. Photoelectric sensors and LiDAR scanners work in conveying, packaging, warehousing and vehicle guidance. Ex-rated tablets and phones are carried on operator rounds and maintenance jobs across GCC oil and gas sites.Ordering Pepperl+Fuchs parts: what we need
Send the complete model designation as printed on the device, including every suffix; a single letter can change the supply voltage or the output type. Add the part number if the label shows one. For barriers, tell us the field device and signal type, the number of channels and whether the safety loop needs a SIL-assessed module. For mobile devices, state the zone or division and the regional radio version.Browse Pepperl+Fuchs products by category: Sensors & Transmitters, Industrial Computer, Isolator & Barrier, Power Modules.
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