The Pepperl+Fuchs KFD2-SR3-EX2.2S serves as the primary KFD2-SR3 Switch Amplifier utilized to execute galvanic isolation and discrete signal conditioning across intrinsic safety (Ex i) barriers platforms.

Nomenclature & Functional Breakdown

• KFD2: K-System housing design for 35 mm DIN rail or Power Rail installation.
• SR3: Switch amplifier functional group with relay contact outputs.
• EX2: Dual-channel galvanically isolated intrinsically safe input circuit.
• 2S: Two active relay outputs per channel (dual changeover or safe-state execution).

Operational Technical Data

Intrinsically Safe Circuit Topology and Shielding Standards

Galvanically isolated channels maintain strict intrinsic safety (Ex i) barriers separation between field field devices and control systems. Standardized housing contours provide high DIN-rail mounting stability under ambient mechanical stress, preventing earth loops while maintaining internal surge voltage protection limits and low protocol conversion latencies across field signal processing loops.

Scope of Delivery

• 1 x Pepperl+Fuchs KFD2-SR3-EX2.2S Switch Amplifier Unit
• 2 x Blue Intrinsically Safe Field Terminal Blocks
• 2 x Black Control Side / Power Supply Terminal Blocks

Field Wiring & Mechanical Assembly

Rail Attachment

Mount the module vertically onto a standard 35 mm DIN rail or integrated Power Rail bus system. Ensure top and bottom housing locking tabs snap securely into place.

Hazardous Area Input Wiring

Terminate field lines from NAMUR sensors or dry contacts at the blue terminals (Terminals 1-3 for Channel 1, Terminals 4-6 for Channel 2). Observe polarity requirements for active NAMUR loops.

Control Side Interconnection

Connect output relay circuits to black terminals 7 through 12. Connect 24 VDC auxiliary power to terminals 14+ and 15- if Power Rail distribution is not utilized.

FAQ Technical Reference

• What sensor types are directly compatible with the input channels of this module?

  Inputs accept standard NAMUR proximity sensors according to EN 60947-5-6 or potential-free mechanical switch contacts.

• How are line fault detection features configured for mechanical switch inputs?

  Resistors must be connected across mechanical contacts (1 kOhm in series, 10 kOhm parallel) to allow line fault monitoring.

• What output action occurs when a field cable break or short-circuit is detected?

  The internal output relay de-energizes into a fail-safe state, and the local fault LED indicates an active line error.

• Can the operating direction of the output relays be inverted on site?

  DIP switches located on the side panel allow independent switching direction setting (normal or inverted) per channel.

• What voltage limit applies to the output relay contact network?

  Relay contacts are rated for switching max. 253 VAC at 2 A or 40 VDC at 2 A non-inductive resistive load.

• How is functional insulation tested between hazardous and non-hazardous terminals?

  Galvanic isolation withstands test voltages up to 2.5 kV AC between input, output, and power supply circuits.

• Is external power wiring necessary when using the module with a Power Rail?

  Direct clip contacts power the unit via Power Rail, rendering individual 24 VDC terminal wiring redundant.

• What conductor cross-sections are supported by the pluggable screw terminals?

  Pluggable terminal blocks accept solid or flexible copper conductors up to 2.5 mm square (AWG 14-24).