Pepperl+Fuchs KCD2 Series Modules: KCD2-SCD-EX1

Technical Dossier

Product Details And Specifications

Pepperl+Fuchs KCD2 Series: Comprehensive Module Range and Technical Overview

The Pepperl+Fuchs KCD2 series is a family of DIN-rail-mounted isolated barriers and signal conditioners engineered for intrinsically safe signal transmission between hazardous-area field instruments and safe-area control systems. Deployed across global heavy industry — including petrochemical complexes, nuclear power facilities, offshore platforms, and crude oil refineries — the KCD2 platform occupies a critical position in process automation infrastructure. Its compact 12.5 mm housing width, passive power supply concept (bus-powered variants), and compatibility with NAMUR sensors and mechanical contacts have made it a de facto standard in Ex ia IIC T6 applications. Installed base spans hundreds of thousands of channels across DCS architectures from Emerson DeltaV, Honeywell Experion, ABB 800xA, and Yokogawa CENTUM VP.

The Evolution of KCD2 Architecture

The KCD2 series succeeded the earlier KFD2 and KFA5 families, consolidating Pepperl+Fuchs's isolated barrier technology into a unified 12.5 mm form factor. Early KCD2 modules (circa 2000–2008) relied on discrete transformer-based isolation with analog signal paths rated to ±0.1% accuracy. The mid-generation revision introduced enhanced EMC shielding and extended the operating temperature range to –20 °C … +60 °C, addressing field requirements in tropical and arctic installations. Current-generation KCD2 modules incorporate SMD manufacturing for improved MTBF figures (typically >500,000 hours) and RoHS-compliant materials. Compatibility note: KCD2 modules use the same KSD2 power rail bus system as the KFD2 series, enabling mixed-generation installations on a single DIN rail segment. KCD2 modules are not pin-compatible with the older KHD2 series and require dedicated terminal blocks. As the KCD2 series has entered its mature/end-of-active-production phase for several sub-types, long-term maintenance support and obsolete part sourcing have become primary procurement concerns for asset owners with 15–25 year plant lifecycles.

KCD2 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly stocked models within the Pepperl+Fuchs KCD2 series, classified by functional category:

Switch Amplifier & Solenoid Driver Modules (NAMUR / Mechanical Contact Input)

• KCD2-SCD-EX1: 1-channel isolated barrier, solenoid/valve driver output, NAMUR input, Ex ia IIC, 12.5 mm housing.
• KCD2-SCD-EX2: 2-channel isolated barrier, dual solenoid driver output, NAMUR sensor input, DIN rail mount.
• KCD2-SR-EX1: 1-channel switch amplifier, relay output (SPDT), NAMUR/mechanical contact input, Ex ia IIC.
• KCD2-SR-EX2: 2-channel switch amplifier, dual relay output (SPDT), NAMUR input, 24 VDC bus supply.
• KCD2-SR-EX2.2S: 2-channel switch amplifier, 2 relay outputs per channel, enhanced short-circuit detection.
• KCD2-SR-EX1.W: 1-channel switch amplifier with watchdog function, relay output, line fault detection.
• KCD2-SR-EX2.W: 2-channel switch amplifier with watchdog, dual relay output, wire-break monitoring.

Analog Input Modules — Transmitter Supply & Signal Conditioners (4–20 mA)

• KCD2-STC-EX1: 1-channel isolated barrier, 4–20 mA transmitter supply and signal conditioner, Ex ia IIC.
• KCD2-STC-EX2: 2-channel transmitter power supply and isolator, 4–20 mA loop, HART transparent.
• KCD2-STC-EX1.2O: 1-channel transmitter supply, dual 4–20 mA output, signal splitter function.
• KCD2-STC-EX2.2O: 2-channel transmitter supply with dual analog outputs, HART pass-through.
• KCD2-STC-EX1.SP: 1-channel transmitter supply with HART signal pass-through, single analog output.

Analog Output Modules — Current Output to Hazardous Area

• KCD2-SOT-EX1: 1-channel isolated barrier, 4–20 mA output to hazardous area, DCS/PLC driven.
• KCD2-SOT-EX2: 2-channel current output isolator, 4–20 mA to field, 750 Ω max load.
• KCD2-SOT-EX1.LB: 1-channel current output with line break detection, fault signaling relay.

Temperature / RTD / Thermocouple Input Modules

• KCD2-UT2-EX1: 1-channel universal temperature input (RTD/TC/mV/Ω), 4–20 mA output, Ex ia IIC.
• KCD2-UT2-EX2: 2-channel universal temperature transmitter interface, configurable via DIP switch.

Power Rail & Bus Accessories

• KSD2-GW: Power rail gateway module, 24 VDC bus supply for KCD2/KFD2 DIN rail segments.

Sourcing Hard-to-Find & Obsolete KCD2 Parts

Quality Control for the KCD2 Range

KCD2 modules present specific test challenges due to their transformer-isolated backplane architecture and NAMUR-standard signal thresholds (8 mA / 1.2 mA switching levels). DriveKNMS applies the following test protocol to all KCD2 units prior to dispatch:

• Dielectric withstand test: 500 VDC isolation verification between input, output, and power circuits.
• NAMUR threshold verification: input switching confirmed at ≤1.2 mA (OFF) and ≥2.1 mA (ON) per EN 60947-5-6.
• Analog accuracy check: 4–20 mA output linearity verified at 0%, 25%, 50%, 75%, and 100% of span against calibrated reference.
• Relay contact resistance: measured at <100 mΩ for all relay output variants.
• Functional burn-in: 4-hour powered soak at 40 °C ambient.

All test records are retained and available upon request with each shipment.