Pepperl+Fuchs K-System Isolation Barrier Complete Guide

3.4 Anti misoperation and height identification of terminals

All pluggable terminals are equipped with red coding pins to prevent mixing of terminals between different devices. There are two heights for terminal blocks:

15mm height: Used for circuits with rated voltage below 50V AC, providing reinforced insulation.

15.5mm height: Used for circuits with rated voltage higher than 50V AC (up to 300V AC), providing basic insulation and marked with an "X" on the terminal side.

The tightening torque of the terminal screw is 0.5 Nm to 0.6 Nm, and the maximum cross-sectional area of the wire is 2.5 mm ² (14 AWG).

Color identification and status indication

4.1 Shell color coding

Pepperl+Fuchs uses color to quickly identify power supply types:

Green: DC 24V power supply.

Black: AC 115V/230V power supply.

Gray: AC/DC wide range power supply (e.g. 24V DC or 115/230V AC).

Blue: Equipment used for processing signals in hazardous areas (intrinsic safety side).

4.2 LED status light (compliant with NAMUR NE44)

All K-System devices are equipped with standardized LED indicator lights:

Green PWR (power supply): Constant light indicates normal power supply; Extinguishing indicates no power supply or insufficient power supply (equipment malfunction).

Red CHK (fault/channel):

Always on: Internal equipment malfunction (equipment replacement required).

Flashing: External circuit failure (such as disconnection or short circuit), on-site wiring needs to be checked.

Extinguish: No malfunction.

Yellow OUT (output status): Used for binary output or analog limit indication. Constant light indicates that the relay is engaged, the transistor is conducting, or the switch signal is valid; Extinguishing indicates disconnection.

In addition, some devices also provide additional yellow LEDs for input status indication.

Operating components and configuration methods

K-System devices support multiple configuration methods to adapt to applications of different complexities.

5.1 DIP switch

Used to select basic functions such as input type (NAMUR or mechanical contact), output mode (normally open/normally closed), filtering time, etc. The switch position is usually printed on the housing or attached to the manual.

5.2 Rotary switch

Used to select range, range, or address (such as a HART multiplexer). Multiple rotary switches can provide multiple discrete gears.

5.3 Potentiometer

Used for fine adjustment of zero position (ZERO) and full scale (SPAN), suitable for analog signal converters. Usually requires adjustment with a small screwdriver.

5.4 Keyboard and LC Display Screen

Some high-end devices (such as general signal converters) are equipped with LCD screens and buttons, which can directly browse measurement values, fault information, and modify parameters locally. Menu navigation usually uses the "ESC" and "OK" keys.

5.5 PACTware ™  Parameterized software

By connecting the programming socket on the device through a dedicated programming adapter (such as K-ADP-USB), the FDT/DTM framework software PACTware can be used to remotely configure, diagnose, and upgrade the firmware of the device. This is particularly useful for devices that require batch settings or complex logic, such as SMART transmitters with HART power supply.

5.6 Explosion proof precautions during configuration

When operating any switch, button, or potentiometer in a hazardous area, it is necessary to ensure that the environment is free of explosive gases, as mechanical action may generate sparks. In addition, static discharge (grounding or equipotential connection) should be performed before operation, and the transparent front cover should only be opened when necessary.

Installation and mechanical requirements

6.1 Installation direction and spacing

K-System equipment has low heat generation, allows for vertical or horizontal installation, and does not require spacing (can be arranged closely). But when the ambient temperature is above 60 ° C (up to 70 ° C), horizontal installation must be used and the minimum spacing must be maintained:

KC (12.5mm) equipment: ≥ 6mm

KF (20mm) equipment: ≥ 10mm

KF (40mm) equipment: ≥ 15 mm

6.2 DIN rail and power rail

Standard installation uses 35mm DIN rails (compliant with EN 60715). To further reduce wiring, K-System provides a Power Rail - a DIN rail with plastic inserts and built-in conductors. There are two versions of power rails:

UPR-03: 3-core (2-core power supply+1-core lumped error signal).

UPR-05: 5 cores (2-core power supply+1-core aggregate error+2-core serial data exchange, only used for specific devices such as KFD2-WAC2).

The power rail is equipped with a cover plate (UPR-COVER) and an end cover (UPR-E) at the factory to prevent contamination and accidental contact. Inject 24V DC power (up to 4A) into the guide rail through a power feeding module (such as KFD0-EB2 series), which can power up to 80 devices. The feed in module also provides replaceable 5A fuses and a lumped error relay output. Attention: It is strictly prohibited to supply power to the power rail through the isolation barrier itself, otherwise it may damage the equipment.

6.3 Traditional wiring (without power rail)