Pepperl+Fuchs KFD2-STC4-Ex1.2O Isolated Barrier

Product Introduction

The Pepperl+Fuchs KFD2-STC4-Ex1.2O is a high-performance isolated barrier tailored for demanding process automation environments. This model is a 1-channel isolated barrier that operates with a 24 V DC supply, compatible with Power Rail systems.

It functions primarily as a signal splitter, accepting one input from a 2-wire or 3-wire SMART transmitter and delivering two identical 0/4 mA ... 20 mA outputs. This design enables seamless integration with distributed control systems while maintaining safety. The device also supports bidirectional digital communication for HART, BRAIN, and Foxboro protocols, ensuring comprehensive SMART device management.

Technical Specifications

The KFD2-STC4-Ex1.2O boasts robust technical parameters that guarantee reliable performance in critical applications.

Input and Output Characteristics

• Input Signal: 0/4 ... 20 mA from field devices.

• Open Circuit Voltage: 22.7 V at terminals 1+, 3-.

• Output Signal: Dual 0/4 ... 20 mA (overload > 25 mA).

• Load Capacity: 0 ... 550 Ω at 20 mA on the control side.

Transfer and Accuracy

• Deviation: ≤ 10 µA at 20 °C, inclusive of calibration and linearity.

• Temperature Influence: Only 0.25 µA/K, ensuring stability across varying ambient conditions.

• Frequency Range: Field side to control side supports 0 ... 7.5 kHz (-3 dB).

• Settling Time: 200 µs, with a rise/fall time of just 20 µs.

Supply and Power

• Rated Voltage: 20 ... 35 V DC (24 V DC nominal).

• Power Consumption: 2.4 W, with a dissipation of 1.8 W.

• Connection: via Power Rail or terminals 14+, 15-.

Functional Safety and Approvals

Safety is paramount in hazardous area instrumentation. Consequently, the Pepperl+Fuchs KFD2-STC4-Ex1.2O is certified for functional safety up to SIL 3 according to IEC/EN 61508.

Furthermore, it holds comprehensive ATEX and IECEx approvals:

• ATEX: [Ex ia Ga] IIC, [Ex ia Da] IIIC, [Ex ia Ma] I for inputs; Ex nA II T4 for outputs.

• IECEx: [Ex ia Ga] IIC and Ex nA IIC T4 Gc.

The galvanic isolation between input, output, and power supply provides safe electrical isolation with a voltage peak value of 375 V, adhering to IEC/EN 60079-11 standards.

Mechanical and Environmental Data

This device is built to withstand industrial environments.

• Ambient Temperature: -20 ... 60 °C (-4 ... 140 °F).

• Degree of Protection: IP20 for the housing.

• Dimensions: 20 x 124 x 115 mm (0.8 x 4.9 x 4.5 inch) - Housing type B2.

• Mounting: Standard 35 mm DIN mounting rail according to EN 60715.

• Connection: Screw terminals with integrated test sockets for easy HART communicator access.

Installation and Integration Guide

Installing the KFD2-STC4-Ex1.2O is straightforward. First, mount the unit on a 35 mm DIN rail. Next, connect the power supply via the Power Rail or terminals 14+ and 15-. Then, wire the field-side input to terminals 1+, 2-, and 3 for transmitters, or terminals 5-, 6+ for current sources.

Similarly, connect the control-side outputs to terminal pairs 7-, 8+,9 and 10-, 11+,12. If the HART communication resistance is insufficient, you can utilize the internal 250 Ω resistor between terminals 8 and 9. The integrated test sockets allow for direct connection of a HART communicator without interrupting the loop.

Packaging and Shipping

Each unit is carefully packaged to ensure safe delivery.

• Packaging List:

  • 1 x KFD2-STC4-Ex1.2O Isolated Barrier

  • 1 x Product Labeling Set

  • 1 x Installation Manual (Digital Download)

• Shipping Methods: Fedex, UPS, DHL

Frequently Asked Questions (FAQ)

Q1: What types of transmitters can I connect to this device?
A: The KFD2-STC4-Ex1.2O supports 2-wire and 3-wire SMART transmitters, as well as 2-wire SMART current sources.

Q2: How do I integrate a HART communicator?
A: You can connect a HART communicator directly to the integrated test sockets on the terminal blocks. Alternatively, use the internal 250 Ω resistor between terminals 8 and 9 as a communication resistance.

Q3: Can I use this unit for SIL-rated safety loops?
A: Yes, this isolated barrier is certified for use in safety loops up to SIL 3 according to IEC/EN 61508.

Q4: What happens if the output is overloaded?
A: The output signal will indicate an overload condition when it exceeds 25 mA, protecting the device and connected systems.

Q5: Does this barrier support bidirectional communication?
A: Absolutely. It supports bidirectional digital signal transmission for HART, BRAIN, and Foxboro SMART protocols, allowing for configuration and diagnostics from the safe area.