PEPPERL+FUCHS KFD2-STC4-EX1.2O 4-20mA Intrinsically Safe Signal Isolator | Replacement, Equivalent & Selection Guide
The PEPPERL+FUCHS KFD2-STC4-EX1.2O is a DIN-rail mounted, 2-wire transmitter power supply and signal isolator designed for use in hazardous area applications. It provides galvanic isolation between field instruments in Zone 0/1/2 and the safe-area control system, making it a critical component in process automation and intrinsic safety barriers.
Technical Specifications
- Model: KFD2-STC4-EX1.2O
- Manufacturer: PEPPERL+FUCHS
- Series: KFD2 (SMART Transmitter Power Supply)
- Function: 2-wire transmitter power supply with signal isolation
- Input: 4–20 mA (HART compatible)
- Output: 4–20 mA, galvanically isolated
- Supply Voltage: 20–35 V DC (via Power Rail or terminals)
- Hazardous Area Classification: Ex ia IIC T6 (Zone 0/1/2)
- Safe Area Output: 1 analog output channel
- Isolation: 3-way galvanic isolation (input / output / power)
- HART Transparency: Yes (pass-through)
- Mounting: DIN rail (35 mm)
- Housing Width: 20 mm
- Operating Temperature: -20 °C to +60 °C
- Protection Degree: IP20
- Certifications: ATEX, IECEx, cULus
- Weight: approx. 100 g
Compatible Replacement & Equivalent Models
If the KFD2-STC4-EX1.2O is unavailable or you are evaluating alternatives, the following models offer compatible or equivalent functionality:
- PEPPERL+FUCHS KFD2-STC4-EX1.O — Single-channel variant without second output; direct functional equivalent for most applications
- PEPPERL+FUCHS KFD2-STC4-EX2.O — Dual-channel version; suitable when two isolated outputs are required
- PEPPERL+FUCHS KFD0-STC4-EX1.O — Compact version without Power Rail; suitable for standalone installations
- MTL5541 (Eaton MTL) — Industry-standard 4-20 mA isolator; widely used as a cross-brand replacement
- MTL5541S (Eaton MTL) — HART-transparent version of MTL5541; direct functional equivalent
- R2-T4-EX (Turck) — DIN-rail 4-20 mA isolator with ATEX certification; compatible in most loop-powered applications
- IM33-12Ex-Hi/24VDC (Phoenix Contact) — Equivalent signal conditioner for Ex Zone 1/2 applications
Note: Always verify Ex certification category, entity parameters (Ui, Ii, Pi, Ci, Li), and loop resistance before substituting any intrinsic safety barrier or isolator.
Why Choose the Original KFD2-STC4-EX1.2O
- Factory-certified ATEX / IECEx / cULus compliance — no re-certification required
- HART signal transparency preserves full asset management capability
- 3-way galvanic isolation eliminates ground loops and protects control systems
- Plug-in terminal blocks and Power Rail compatibility reduce installation time
- Proven reliability in oil & gas, chemical, and pharmaceutical plants worldwide
- Full traceability and manufacturer warranty
Typical Applications
- Powering 2-wire 4-20 mA transmitters (pressure, temperature, flow, level) in hazardous zones
- Signal isolation between field instruments and DCS / PLC / SCADA systems
- HART device communication in Ex Zone 0 / Zone 1 environments
- Petrochemical and refinery process control panels
- Pharmaceutical clean-room and solvent-handling areas
- Offshore platform instrumentation loops
System Compatibility
- DCS: Emerson DeltaV, Honeywell Experion, ABB 800xA, Yokogawa CENTUM VP
- PLC: Siemens S7-300/400/1500, Allen-Bradley ControlLogix, Schneider Modicon M340/M580
- Power Rail: Compatible with PEPPERL+FUCHS KF-RAIL Power Rail system
- HART Multiplexers: Compatible with standard HART multiplexer infrastructure
- Mounting: Standard 35 mm DIN rail (EN 60715)
Selection Guide
Use the table below to select the correct KFD2-STC4 variant for your application:
- KFD2-STC4-EX1.O — 1 channel, 1 output, Power Rail supply → Standard single-loop isolation
- KFD2-STC4-EX1.2O — 1 channel, 2 outputs, Power Rail supply → When one field input must feed two independent safe-area outputs (e.g., DCS + recorder)
- KFD2-STC4-EX2.O — 2 channels, 2 outputs, Power Rail supply → Dual independent loops in one housing
- KFD0-STC4-EX1.O — 1 channel, 1 output, terminal supply → No Power Rail; standalone or retrofit panels
Key selection parameters: number of field channels, number of safe-area outputs required, Power Rail vs. terminal supply, HART requirement, and Ex entity parameters of the connected field device.
Quality Assurance & Sourcing
- All units sourced from authorized distributors or verified surplus channels
- Each unit inspected for physical integrity, label authenticity, and firmware/hardware revision
- Original manufacturer packaging and documentation preserved where available
- Traceable lot records maintained for compliance audits
- Konmask.com specializes in industrial automation components for MRO and project procurement
How to Order
- Part Number: KFD2-STC4-EX1.2O
- Manufacturer: PEPPERL+FUCHS
- Add to cart directly, or contact us for bulk pricing, lead time, and datasheet requests
- Email: [email protected]
- Phone / WhatsApp: +0086 19859288691
- We support T/T, PayPal, and trade assurance payment terms
Replacement & Compatibility FAQ
Q: Can I replace KFD2-STC4-EX1.2O with KFD2-STC4-EX1.O?
A: Only if your application requires a single safe-area output. The EX1.2O provides two isolated outputs from one field input; the EX1.O provides only one.
Q: Is the KFD2-STC4-EX1.2O HART transparent?
A: Yes. HART signals pass through both outputs, enabling full HART communication from the safe area.
Q: Can MTL5541S replace the KFD2-STC4-EX1.2O?
A: The MTL5541S is functionally similar for single-output loops but does not provide a second isolated output. Verify entity parameters and loop resistance before substitution.
Q: Does this unit require a Power Rail?
A: The KFD2-STC4-EX1.2O is designed for Power Rail supply. For terminal-only supply, use the KFD0-STC4-EX1.O variant.
Q: What is the maximum loop resistance supported?
A: Refer to the official PEPPERL+FUCHS datasheet for entity parameters. Konmask can provide the datasheet upon request.
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