Product Overview

The Pepperl+Fuchs KFD2-STC5-1 acts as a high-performance isolated barrier within the renowned K-System, specifically designed to power 2-wire and 3-wire SMART transmitters in hazardous areas. This single-channel module ensures the integrity of critical process data by providing high-quality galvanic isolation between the field loops and the control system. By supporting bi-directional communication via the HART protocol, the KFD2-STC5-1 allows engineers to perform remote diagnostics and configuration without interrupting the 4 mA ... 20 mA analog signal. This unit plays a vital role in protecting expensive DCS and PLC inputs from unpredictable surges and ground loops, making it an essential component for oil and gas, chemical processing, and power generation facilities where signal precision is non-negotiable.

Core Technical Advantages

This module features a specialized transformer-based isolation architecture that provides robust galvanic separation between the input, output, and power supply. The KFD2-STC5-1 delivers a stable 24V DC supply to field instrumentation while simultaneously transferring the analog measurement signal to the safe area with negligible linearity error. Its hardware design includes a dedicated terminal set for HART communicators, allowing for seamless integration of handheld devices or PC-based asset management software. The unit also incorporates active current limiting and short-circuit protection, preventing localized field faults from cascading into systemic failures. Furthermore, the housing utilizes a standard 35 mm DIN rail mount with Power Rail compatibility, which simplifies wiring by distributing power through the rail connectors rather than individual terminal blocks.

Technical Specifications

Installation Guide

Engineers must install the KFD2-STC5-1 vertically on a 35 mm DIN rail within a protected enclosure to ensure optimal heat dissipation. When wiring 2-wire transmitters, connect the positive lead to terminal 1 and the negative to terminal 3; for 3-wire configurations, utilize terminal 2 for the power feed. Maintain a minimum bending radius of 20mm for all signal cables to prevent conductor fatigue and signal attenuation. For HART communication, ensure that the loop resistance remains between 250 Ω and 1100 Ω to allow the digital frequency shift keying (FSK) signal to propagate correctly. If installing multiple units, utilize the KFD2-EB2 Power Feed Module to streamline the power distribution across the Power Rail, significantly reducing installation labor and potential wiring errors.

Engineering Advantages

The KFD2-STC5-1 excels in high-interference environments by filtering out electromagnetic noise that often plagues long-distance signal transmission in industrial plants. Its Sil 2 (IEC 61508) capability demonstrates its reliability for use in safety-instrumented systems where high availability is paramount. The module’s compatibility with both 2-wire and 3-wire transmitters provides engineers with the flexibility to standardize on a single barrier model across diverse instrument types. By decoupling the field environment from the control room, this isolated barrier prevents ground loop currents from distorting sensor data, ensuring that your process control logic operates on accurate, real-time information.

Delivery & Logistics

Delivery Time: 3-5 days once payment is finalized.Shipping Carriers: Shipped via DHL, FEDEX, or UPS with full tracking and original factory sealing.

Technical FAQs

Q1: Does the KFD2-STC5-1 support 3-wire transmitters with higher current consumption?A1: Yes, this module provides a dedicated terminal for 3-wire power, though you should verify that the transmitter's total current draw does not exceed the unit's maximum output capacity (typically around 25 mA).

Q2: Can I access HART data through the output terminals?A2: Absolutely. The KFD2-STC5-1 is designed for HART transparency, meaning the digital signal passes through the barrier without distortion, allowing you to connect a HART modem at the control side terminals.

Q3: What is the benefit of using the Power Rail with this model?A3: The Power Rail eliminates the need for "daisy-chaining" 24V DC wires across every individual module. It provides a centralized power bus, reduces cabinet clutter, and allows for hot-swapping modules without losing power to the rest of the rack.

Q4: How does the KFD2-STC5-1 handle a short circuit in the field?A4: The module incorporates internal current limiting. In the event of a field-side short circuit, the barrier limits the current to a safe level, protecting the internal circuitry and preventing the fault from tripping the main power supply.