KFD2-SR2-Ex1.W Switch Amplifier – NAMUR Input, ATEX, FM Approved

KFD2-SR2-Ex1.W Switch Amplifier – Intrinsic Safety Barrier

• Brand: Pepperl+Fuchs
• Model: KFD2-SR2-Ex1.W
• Type: 1-channel isolated barrier switch amplifier
• Application: Dry contact or NAMUR inputs in hazardous areas
• Key function: Relay contact output with line fault detection (LFD)
• Safety level: SIL 2 (SC 3) per IEC/EN 61508
• Approvals: ATEX, FM, CSA, UL (entity parameters included)

Key Benefits at a Glance

• 24 V DC supply (Power Rail compatible)
• Reversible mode of operation for flexible control
• Relay output: 253 V AC / 2 A or 40 V DC / 2 A
• Line fault detection (LFD) for breakage monitoring
• Safe isolation: Input/Output 375 V peak
• Wide ambient temperature range: -20 °C … +60 °C

Technical Data – Compact Overview

• Supply:
  • Rated voltage: 20 … 30 V DC (ripple ≤ 10 %)
  • Rated current: 20 … 23 mA
  • Power loss: 0.4 W; consumption < 1 W
• Input (terminals 1+, 3-):
  • NAMUR acc. EN 60947-5-6
  • Open circuit voltage: ~8 V DC / short-circuit current ~8 mA
  • Switching point: 1.2 … 2.1 mA (hysteresis ~0.2 mA)
  • Pulse/Pause ratio: ≥ 20 ms / ≥ 20 ms
  • Lead monitoring breakage: I ≤ 0.1 mA
• Output (terminals 7, 8, 9):
  • Relay contact: 253 V AC / 2 A (cos ϕ > 0.7) or 40 V DC / 2 A resistive
  • Energised/de-energised delay: ~20 ms
  • Mechanical life: 10⁷ switching cycles
• Transfer characteristics: Switching frequency < 10 Hz
• Electrical isolation:
  • Input/Output safe isolation (375 V peak)
  • Input/Power supply safe isolation (375 V peak)
  • Output/Power supply rated insulation 253 Veff
• Ambient conditions: -20 … 60 °C (IP20 protection)
• Mass: approx. 150 g

Ex-Data & Entity Parameters (Hazardous Areas)

• EC-Type Examination Certificate: PTB 00 ATEX 2080
• Group, category: II (1) G D [EEx ia] IIC (zone 0/1/2)
• Safety maximum voltage Um: 253 V AC / 125 V DC
• Type of protection: [EEx ia] and [EEx ib]
• Entity parameters (input):
  • U0 = 10.5 V; I0 = 13 mA; P0 = 34 mW
  • External capacitance (IIC): 2.41 µF / inductance: 210 mH
  • For IIB: 16.8 µF / 840 mH; for IIA: 75 µF / 1000 mH
• FM / CSA / UL control drawings: No. 116-0035, 116-0047, LR 36087-13, E 106378
• Safety parameter (UL): 12.6 V / 650 Ohm

Installation & Commissioning Notes

• Mount on 35 mm DIN rail (Power Rail optional)
• Use terminals 14+ and 15- for supply (or Power Rail)
• Input wiring: terminals 1+ and 3- (NAMUR or dry contact)
• Output relay: terminals 7 (common), 8 (NO), 9 (NC)
• Line fault detection (LFD) automatically monitors breakage
• Reversible mode via DIP switch or wiring
• Check polarity and isolation before power-up

Maintenance & Serviceability

• No routine maintenance required; solid-state design
• Easy fault finding with LED indicators (power, status, fault)
• Replace plug-in terminal blocks without rewiring
• Compact size saves cabinet space
• Compatible with standard automation systems

Compatibility & System Integration

• Works with all NAMUR sensors (EN 60947-5-6)
• Relay output interfaces with PLC, DCS, or alarm panels
• Suitable for SIL 2 loops (SC 3) per IEC 61508
• Approved for Zone 0, 1, 2 (gas) and Zone 20, 21, 22 (dust)
• Power Rail compatible for daisy-chain supply

Certifications & Standards

• ATEX: PTB 00 ATEX 2080
• FM: J.I.3002773 (Division 2 suitable)
• CSA: LR 36087-13
• UL: E 106378
• EMC: EN 50081-2 / EN 50082-2, NE 21
• Insulation: DIN EN 50178

Package Contents

• 1 x KFD2-SR2-Ex1.W switch amplifier
• Terminal block set (plug-in)
• Quick start guide (English)
• ATEX / FM control drawing supplement

Warranty & Shipping

• Warranty: 12 months from invoice date
• Shipping: 12–24 hours dispatch (excl. weekends)
• Carriers: FedEx, UPS, DHL (trackable)
• Global express delivery available

Expert Review – Manager’s Insight

• “Robust, reliable, and easy to commission. The KFD2-SR2-Ex1.W offers true galvanic isolation and LFD, reducing field wiring errors. Its SIL 2 capability makes it a first choice for safety-related applications.” – Senior Product Manager, PowergearX
• “We tested this amplifier in harsh chemical plants. It performed flawlessly at extreme temperatures. The relay contacts handle inductive loads well. A solid investment for critical loops.” – Automation Engineer, 12+ years

Typical Applications

• Level / flow / pressure switches in explosive atmospheres
• Valve position feedback in Zone 1 / 2 areas
• Rotary speed monitors and proximity sensors
• Safety interlock circuits (SIL 2)
• Oil & gas, chemical, pharmaceutical, and mining industries

FAQ – Frequently Asked Questions

• Can I use this with a 2-wire proximity sensor?

  Yes. It accepts NAMUR sensors or dry contacts. Set the DIP switch accordingly.

• What happens if the line breaks?

  The LFD detects current < 0.1 mA and triggers a relay alarm.

• Is the relay output fail-safe?

  You can select energised or de-energised mode. Choose based on your safety philosophy.

• Can I power it from a 24 V DC PLC supply?

  Yes. The rated voltage range is 20–30 V DC, suitable for most industrial supplies.

• What is the maximum switching frequency?

  Below 10 Hz due to relay mechanics. For faster signals, consider a transistor output version.

• How do I reset after a fault?

  Cycle power or correct the input fault. The relay automatically resets.

• Is the unit certified for Division 2?

  Yes. See FM control drawing 116-0035 for Division 2 installation.

Selection Guide – Which model to choose?

• Choose KFD2-SR2-Ex1.W for relay output and LFD.
• If you need transistor output, select KFD2-SR2-Ex1.W (transistor variant).
• For high switching speed (> 10 Hz), use KFD2-SR2-Ex1.W with solid-state output.
• All versions share the same housing, terminal layout, and Ex parameters.
• Contact our technical support for tailored recommendations.

Contact Information
Sales inquiries: sales@powergearx.com
Technical support: +86 18030005825 (WhatsApp)

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