PEPPERL+FUCHS SLVA-4Kplus Safety Light Curtain Guide

Pepperl+Fuchs SLVA-4Kplus Safety Light Curtain Control Unit: A Comprehensive Guide from Installation to Troubleshooting

In the field of industrial automation, safety protection systems are the first line of defense to ensure the safety of personnel and equipment. Non contact electrical sensitive protective equipment (ESPD) has become the mainstream choice for entrance protection in hazardous areas due to its advantages of no mechanical wear, rapid response, and no hindrance to operation. The SLVA-4Kplus control unit launched by Pepperl+Fuchs, combined with SLA series safety light curtains or SLP series safety gratings, forms a high-performance safety light curtain system that complies with Type 4 (EN 61496-1), Category 4 (ISO 13849-1), PL e, and SIL 3 levels. This article is based on the original factory technical manual and provides a complete operation guide for automation engineers, safety system integrators, and maintenance personnel, covering product characteristics, installation wiring, mode settings, debugging steps, fault diagnosis, and regular inspections.

Chapter 1: Product Overview and System Composition

1.1 Product positioning and safety level

The SLVA-4Kplus is a control unit designed specifically for 1 to 4 single beam safety light curtains or gratings. It cannot work independently and must be used in conjunction with Pepperl+Fuchs approved SLA type light curtains or SLP type gratings. The system has reached the following security levels:

Type 4（EN 61496-1）

Category 4（ISO 13849-1）

Performance Level PL e（EN ISO 13849）

SIL 3（IEC 61508）

This means that the control system can maintain safety functions even in the event of a single failure and has self-monitoring capabilities, making it suitable for protecting high-risk machinery in hazardous areas.

1.2 System Components

A complete light curtain security system includes:

1 to 4 sets of single beam light curtains (transmitter+receiver) or SLP gratings

SLVA-4Kplus control unit

Optional: 2-channel emergency stop switch monitoring circuit

The control unit provides working power for the light curtain, drives the transmitter, and processes the receiver signal. The built-in microprocessor continuously monitors the light curtain function, and two positive directional relays (forcibly disconnect) cut off the safety output (OSSD) when the beam is obstructed. The control unit also supports DIP switch selection for multiple operating modes and can output status signals such as "ready/fault", "safety output off", "safety output on", etc.

1.3 Product Features

Self monitoring, modular structure

Monitoring relay output (EDM, external device monitoring)

Optional with/without start/restart interlock

Optional relay monitoring function

Fault diagnosis digital display, easy to locate

Protection level IP20/NEMA 1, to be installed in control cabinets above IP54

Supports up to 4 protection beams

Red visible light, easy to adjust for light

Both the receiver and control unit are equipped with stability control indicators

Can monitor 2-channel safety circuit (emergency stop circuit)

Chapter 2: Terminal Definition and Wiring Instructions

The SLVA-4Kplus adopts a screw terminal block, and all connections are completed through the front terminals. The terminal functions are shown in the following table:

Terminal Function Description

1-2 Testing/Fault Clearing: Normally open contacts must be closed during normal operation; Used for testing or fault reset

3-4 Start/restart enable normally open contacts to be closed for 0.05-1 seconds in interlock mode for startup; Keep normally open in interlock free mode

5-6 OSSD status LED direct drive can be directly connected to red/green LED (without series resistance), with a current of about 9mA; optional relay output version (2528 option)

For the connection of the 7-14 light curtain receiver or emergency stop circuit, please refer to Chapter 5 Wiring Diagram

15-16 Start ready/fault status indicator light output passive contact, requires external power supply to drive yellow indicator light

17-18 power input DC version with arbitrary polarity; Communication version has no polarity requirement

19-22 Safety Relay Output (OSSD) with two sets of normally open contacts, used to control the main circuit of the machine

23-24 Relay Monitoring Input (EDM) is only used when the relay monitoring function is enabled, in series with external relay normally closed contacts

25-32 light curtain emitter connected with two wires per channel (4 channels in total)

2.1 Fuse

The safety output is equipped with replaceable fuses: one T2.0A fuse for each of 19-20 and 21-22. Before replacing the fuse, the power supply of the control unit must be disconnected and the lower terminal block must be removed.

2.2 Cable length limit

Maximum length of cable between control unit and light curtain: 50 meters

Maximum cable length between control unit and system (such as emergency stop button): 100 meters

Chapter 3: Operation Mode Settings - Detailed Explanation of DIP Switches

The SLVA-4Kplus sets the operating mode through 4 sets of DIP switches (a total of 8 positions). It is pre-set according to the order code when it leaves the factory, and users can change it themselves. The functional verification must be completed before the system is put into use after the change. The DIP switch is located under the transparent cover on top of the control unit and can be set by prying it open with a screwdriver.