Pepperl+Fuchs KFD2-UT2-Ex1 – Universal Intrinsically Safe Temperature Transmitter/Isolated Barrier for Hazardous-Area Sensors

The P+F KFD2-UT2-Ex1 is a compact, 1-channel universal temperature transmitter/isolated barrier from the K-System series. From my experience, it’s a practical pick when you need to bring RTDs, thermocouples, or low-level voltage/resistance signals from hazardous areas into a safe-area control system as a clean 4–20 mA signal. You might notice that it cuts down cabinet space and wiring complexity compared with using separate transmitters in the field—especially when you standardize on DIN-rail-mounted interface modules.

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Key Features

• Universal input – Accepts RTDs (e.g., Pt100/Pt1000), thermocouples (J, K, T, E, N, R, S, B), resistance, and low-level mV signals, so one model covers most temperature measurement tasks.
• 4–20 mA isolated output – Delivers a stable, noise-resistant current loop to your DCS/PLC; typically reduces grounding headaches in mixed-signal panels.
• Intrinsic safety (Ex i) barrier – Interfaces sensors in hazardous zones with galvanic isolation, helping you meet plant safety requirements.
• DIN-rail form factor – Slim 20 mm housing fits dense cabinets; compatible with P+F Power Rail for clean power distribution in many cases.
• Configurable ranges – Input types and measurement ranges are set via on-device configuration (no field transmitter at the sensor, which many technicians prefer).
• Diagnostics – Open/short sensor detection and out-of-range indication help maintenance teams pinpoint issues faster.

Technical Specifications

Application Fields

This model typically shows up wherever temperature needs to be measured in hazardous areas but processed in the safe area:

• Chemicals and petrochemicals – Reactors, heat exchangers, tank farms with Ex-rated probes.
• Oil & Gas – Separators, heaters, pipelines, and skid packages where Ex compliance is mandatory.
• Pharmaceuticals – Clean utilities and process vessels with validated temperature loops.
• Power generation – Boiler lines and fuel handling areas that may require intrinsic safety.
• Food & Beverage – CIP/SIP temperature monitoring with sanitary RTDs in classified zones.
• Water/Wastewater – Digesters and chemical dosing rooms where safe interfacing is preferred.

A maintenance lead told me their biggest win was standardizing on K-System rails—swapping a KFD2-UT2-Ex1 takes minutes, and the loop is back up without reworking the panel.

Advantages & Value

• Reliability – Stable signal conditioning with robust isolation; it seems to be less sensitive to cabinet noise than many field transmitters.
• Compatibility – Works neatly with most DCS/PLC 4–20 mA inputs; broad sensor support reduces model diversity.
• Cost savings – In many cases, keeping the transmitter in the safe area lowers Ex installation costs versus smart head transmitters in the field.
• Panel efficiency – 20 mm width and Power Rail option help with tidy, scalable builds and faster expansion.
• Serviceability – Quick replacement and straightforward on-device setup; typically no special software needed for standard ranges.

Installation & Maintenance

• Panel environment – Install on a 35 mm DIN rail inside an IP-rated enclosure; allow basic airflow. Keep within -20…+60 °C and avoid condensation.
• Wiring – Use twisted pairs for low-level sensor inputs. Maintain separation from high-voltage lines. Follow intrinsic safety entity parameters for the Ex field circuit.
• Grounding/earthing – Bond the panel per plant standards; proper grounding usually improves noise immunity and stability.
• Configuration – Set input type and range on the device. Verify scaling and loop direction on the control system side before handover.
• Safety – De-energize before wiring. Confirm barriers and field devices are matched for Ex i. Document loop drawings for inspections.
• Routine checks – Periodic loop verification with a dry-block or signal simulator is recommended. Clean terminals, re-torque connections, and review calibration intervals based on process criticality.

Quality & Certifications

• CE and RoHS compliant
• ATEX/IECEx approvals for intrinsic safety (device-dependent marking)
• cULus recognition for North America (typical for K-System modules)
• Manufactured under ISO 9001 quality systems
• Manufacturer’s warranty: 12 months (365 days)

If you’re consolidating mixed sensor types into a single conditioning platform, KFD2-UT2-Ex1 is a safe bet—especially when you want predictable 4–20 mA loops from Ex areas without installing smart heads at the probe. One thing I appreciate is how it simplifies spares: one module covers most temperature inputs you’ll encounter on site.