Pepperl+Fuchs K-System Isolation Barrier Complete Guide

Dimensions: Various shapes, width 12.5/20/40/60 mm, height approximately 107-131 mm, depth 114-115 mm. Please refer to the data sheets of each model for details.

Model code analysis

The K-System model follows a systematic coding rule (e.g. KFD2-STC4-Ex1). The typical structure is as follows:

Position 1: K=K-System

Position 2: C (12.5mm pluggable terminal), F (20/40mm pluggable terminal), H (20/40mm non pluggable terminal)

Position 3: D (DC power supply), A (AC power supply), U (AC/DC wide power supply)

Position 4:0 (no power supply), 2 (24V), 4 (100V), 5 (115V), 6 (230V), 8 (24V DC or 115/230V AC)

Position 5: Function code (such as STC=SMART transmitter power supply with current output, SR=switch amplifier with relay output, TR=thermal resistance converter, etc.)

Subsequently, it may also include Ex identification, number of channels, etc.

The complete model definition needs to refer to the product data sheet.

Dismantling, maintenance, and scrapping

11.1 Disassembly steps

Disconnect the power supply and ensure that all circuits are out of power.

Insert a straight screwdriver into the groove of the red installation slider at the bottom of the device, and rotate it to make the slider pop out.

Repeat on the other side and remove the device from the DIN rail.

11.2 Maintenance Principles

The K-System equipment is not repairable (there are no user replaceable parts). If the equipment is damaged or malfunctioning, it must be replaced with original Pepperl+Fuchs spare parts. It is strictly prohibited to modify or repair explosion-proof equipment. When cleaning, only dry cloth should be used to avoid electrostatic discharge.

11.3 Scrap disposal

Recycle according to local electronic waste regulations. The equipment does not contain hazardous substances (compliant with RoHS), but should be avoided from being discarded indiscriminately.

Typical Applications and Selection Suggestions

12.1 Application Scenarios

Petrochemical industry: Transmit 4-20mA transmitter signals from Zone 1 to the safe zone while providing intrinsic safety power supply.

Pharmaceutical: Isolate solenoid valve drive to ensure safe operation of Ex ia valves in clean rooms.

Water treatment: Convert the NAMUR level switch signal into relay contacts to drive the pump.

Power: Isolation conversion of temperature sensor (Pt100) to avoid grounding loops.

Industrial gases: frequency signals (such as turbine flow meters) are converted into standard analog quantities.

12.2 Selection steps

Determine input signal type: 4-20mA active/passive? NAMUR？ Pt100？ Thermocouple? Frequency?

Determine the output signal type: 4-20mA to PLC? Relay to motor? Transistors to indicator lights?

Confirm power supply: Does the cabinet have a 24V DC power supply? Or is it only 230V AC? Is a power rail used?

Explosion proof rating: Ex ia IIC T4 is usually sufficient. Confirm the matching of intrinsic safety parameters of on-site equipment with isolation barriers (maximum allowable voltage, current, power).

Special feature: Do you need HART transparent transmission? Do you need line fault detection? Is SIL level (functional safety) required?

Width and density: Computer cabinet space, choose 12.5mm or 20mm equipment.