SICK 6044738 WL280-2H4331 Relay Retro-Reflective Sensor

Technical Overview

The SICK WL280-2H4331 is a dual-lens retro-reflective photoelectric sensor with an electrically isolated change-over relay. A passive reflector returns the visible red beam, allowing opaque objects to be detected by beam interruption. Sensing extends from 0.01–13 m with PL80A or 0.01–11 m with P250; corresponding maximum ranges are 15 m and 12 m. A potentiometer adjusts reception, and the relay operates in light-switching mode. The sensor accepts 24–240 V AC or DC, with response of no more than 15 ms and 33 Hz switching. An IP66/IP67 ABS housing and a cable-gland connection support installation; P250 and BEF-W280 are supplied.

Relay retro-reflective sensor with 0.01–13 m with PL80A; 0.01–11 m with P250, visible red LED sensing and Cable gland.

Key Features

Dual-lens retro-reflective detection

0.01–13 m sensing with PL80A; 0.01–11 m with P250

Maximum range 15 m with PL80A; 12 m with P250

Visible red LED; Ø260 mm spot at 8 m

Sensitivity adjustment by potentiometer

Isolated change-over relay; light switching

Relay ratings 3 A at 240 V AC or 30 V DC

Response ≤15 ms; 33 Hz switching

24–240 V AC/DC operation; Cable gland

IP66/IP67 ABS housing; P250 reflector and BEF-W280 bracket supplied

Technical Specification Matrix

Parameter	Value
Functional principle	Photoelectric retro-reflective sensor
Sensing range	0.01–13 m with PL80A; 0.01–11 m with P250
Maximum sensing range	0.01–15 m with PL80A; 0.01–12 m with P250
Switching output	Relay
Optical design	Dual lens; minimum distance to reflector
Light source	LED, visible red light
Light spot size	Ø260 mm at 8 m
Adjustment	Potentiometer
Switching mode	Light switching
Relay output function	Electrically isolated change-over contacts
Relay switching ratings	3 A at 240 V AC; 3 A at 30 V DC
Load suppression	Suitable spark suppression required for inductive or capacitive loads
Power supply	24–240 V AC or 24–240 V DC; ±10%
Power consumption	≤5 VA
Response time	≤15 ms
Switching frequency	33 Hz at light/dark ratio 1:1
Connection	Cable gland
Circuit protection	Supply reverse-polarity protection and interference suppression
Protection class	II; rated voltage 250 V AC/DC
Overvoltage category	2
Housing form	Rectangular
Housing material	ABS plastic
Optics material	PMMA plastic
IP rating	IP66 and IP67
Items supplied	BEF-W280 mounting bracket; P250 reflector
Usage category	AC-15, DC-13 according to EN 60947-1
Electromagnetic compatibility	EN 60947-5-2
Operating temperature	−25 to +55 °C
Storage temperature	−40 to +70 °C
MTTFD	1,537 years
Diagnostic coverage DCavg	0%
Interference emission	EN 61000-6-3; for DC supply the cable from supply source to sensor must be shorter than 30 m
Dimensions L x W x H (cm)	6.3 x 2.35 x 7.45
Physical Weight (kg)	0.15

Parameter

Value

Functional principle

Photoelectric retro-reflective sensor

Sensing range

0.01–13 m with PL80A; 0.01–11 m with P250

Maximum sensing range

0.01–15 m with PL80A; 0.01–12 m with P250

Switching output

Relay

Optical design

Dual lens; minimum distance to reflector

Light source

LED, visible red light

Light spot size

Ø260 mm at 8 m

Adjustment

Potentiometer

Switching mode

Light switching

Relay output function

Electrically isolated change-over contacts

Relay switching ratings

3 A at 240 V AC; 3 A at 30 V DC

Load suppression

Suitable spark suppression required for inductive or capacitive loads

Power supply

24–240 V AC or 24–240 V DC; ±10%

Power consumption

≤5 VA

Response time

≤15 ms

Switching frequency

33 Hz at light/dark ratio 1:1

Connection

Cable gland

Circuit protection

Supply reverse-polarity protection and interference suppression

Protection class

II; rated voltage 250 V AC/DC

Overvoltage category

Housing form

Rectangular

Housing material

ABS plastic

Optics material

PMMA plastic

IP rating

IP66 and IP67

Items supplied

BEF-W280 mounting bracket; P250 reflector

Usage category

AC-15, DC-13 according to EN 60947-1

Electromagnetic compatibility

EN 60947-5-2

Operating temperature

−25 to +55 °C

Storage temperature

−40 to +70 °C

MTTFD

1,537 years

Diagnostic coverage DCavg

Interference emission

EN 61000-6-3; for DC supply the cable from supply source to sensor must be shorter than 30 m

Dimensions L x W x H (cm)

6.3 x 2.35 x 7.45

Physical Weight (kg)

0.15

Industrial Applications

1. Counting separated opaque cartons

A carton conveyor can mount the sensor on one side and a suitable passive reflector on the other. Each separated opaque carton interrupts the returned red beam and changes the switching output for the machine counter. The reflector-dependent sensing range defines the available optical span, and actual target spacing must allow distinct transitions.

Problem Solved

Each qualified carton passage produces a discrete electrical event for counting, while the passive reflector avoids the need to route a receiver power cable across the conveyor.

Opaque cartons Relay Retro-reflective

2. Monitoring accumulation at a transfer point

At a conveyor transfer, a load remaining between the sensor and reflector holds the optical path in the blocked condition. The machine controller can evaluate the duration of this state to identify sustained occupancy. Light switching provides the detection logic, and the electrical connection links the sensor to local machine wiring.

Problem Solved

A sustained beam blockage identifies a transfer position that remains occupied, helping the controller coordinate upstream release before additional loads enter the same constrained space during production.

Load accumulation Light switching Beam interruption

3. Checking opaque sheet continuity

An opaque sheet feeder can direct the returned optical beam through the expected material path so an intact sheet normally blocks received light. A break or runout restores light and changes the switching state. Visible red illumination assists initial positioning, while the documented enclosure rating supports exposed mounting in the machine.

Problem Solved

A change in the received-light state gives the controller an electrical indication of missing material at the monitoring position, supporting a coordinated response when sheet feed is interrupted.

Opaque sheet Visible red light Material continuity