Pepperl+Fuchs KFD2-STC4-1

Technical & Electrical Specifications

• Rated Supply Voltage: 20 V DC ~ 35 V DC
• Total Module Power Consumption: 1.8 W
• Max Power Dissipation: 1.4 W
• Per-Channel Field Input Terminals: 1+,2-,3 / 5-,6+
• Field Input Signal Range: 0 mA ~ 20 mA / 4 mA ~ 20 mA
• Minimum Available Field Loop Voltage @ 20 mA: ≥ 16 V DC
• Max Voltage Drop Across Input Terminals @ 20 mA: ≤ 2.4 V DC
• Control Side Output Terminals: 7-,8+,9 per channel
• Output Signal Range: 4 mA ~ 20 mA; overload cutoff > 25 mA
• Max Permissible Output Load Resistance: 800 Ω at 20 mA
• Output Signal Ripple Noise: ≤ 50 µA eff
• Total Measurement Deviation @ 20 °C Full Scale: ≤ 10 µA
• Temperature Drift Coefficient: ≤ 20 ppm/K
• Input/Output Bandwidth (-3 dB): 0 Hz ~ 7.5 kHz
• Signal Settling Time: 200 µs
• Isolation Standard: Basic insulation EN 50178
• Rated Insulation Voltage: 253 V eff
• Functional Safety Rating: SIL 2 IEC 61508
• Fault Detection Threshold: Signal outside 3 mA ~ 22 mA triggers dedicated fault relay output

Mechanical & Material Specifications

• Overall Dimension (W × H × D): 20 mm × 124 mm × 115 mm
• Housing Material: Flame-retardant green polycarbonate V0 grade
• Protection Class: IP20 cabinet-only installation
• Mounting Standard: 35 mm EN 60715 DIN rail
• Connection Terminals: Screw clamp wire terminals
• Net Weight: Approx. 200 g

Environmental Parameters

• Operating Ambient Temperature: -20 °C ~ +60 °C
• Storage Temperature Range: -30 °C ~ +70 °C
• Pollution Degree Class 2, Overvoltage Category II

Function Features

1. Four independent fully isolated analog channels for multi-transmitter parallel signal conditioning
2. Bidirectional transparent HART digital communication pass-through for SMART transmitter remote calibration
3. DIP switch configurable output mode: current source, current sink, voltage source
4. Global common disable input to lock all four channel outputs simultaneously
5. Per-channel line fault detection for open circuit / short circuit field wiring faults
6. SIL 2 certified for non-hazardous safety instrumented analog control loops
7. Wide 20–35 V DC universal industrial power supply input range

Working Principle

Advantage Highlights

1. Four-channel compact design reduces DIN rail cabinet space versus single-channel isolators
2. Full HART transparency eliminates need for separate HART multiplexer hardware
3. Built-in common global disable input simplifies emergency process shutdown logic
4. Ultra-fast 200 µs settling time supports high-speed closed-loop process control
5. Low temperature drift ensures consistent measurement accuracy across full operating temperature band
6. SIL 2 certification allows deployment in non-hazardous safety critical control systems

Applicable Industries

Installation Requirements

1. Install exclusively inside IP40+ sealed electrical control cabinets
2. Mount horizontally on standard 35 mm top-hat DIN rail; vertical mounting prohibited
3. Separate field sensor wiring and control system wiring via internal cabinet cable dividers
4. Supply power must be stabilized SELV 24 V DC industrial power supply unit
5. Maintain minimum 8 mm horizontal gap between adjacent heat-generating power modules

Usage Precautions

1. Do not connect module to field wiring located within classified hazardous gas/dust zones
2. Total output load resistance must not exceed 800 Ω per individual channel
3. For SIL safety loop deployment, perform annual full function calibration verification
4. Avoid installation adjacent to high-frequency variable frequency drive (VFD) power modules without EMC shielding
5. Disconnect power supply before modifying DIP switch configuration settings
6. Do not daisy-chain multiple KFD2-STC4-1 modules on single unregulated power rail