SICK 6043920 WFS3-40N415 NPN Label Fork Sensor

Technical Overview

The SICK WFS3-40N415 is an infrared optical fork sensor for label detection with an NPN output. Its 3 mm opening and 42 mm fork depth provide a fixed sender–receiver path within one glass-fiber-reinforced PA housing. The specified minimum label size and gap are 2 mm, depending on label thickness. Plus/minus buttons and an external teach connection support threshold setup, with two-point and dynamic teach-in available. Selectable light/dark switching adapts the machine signal. Response of no more than 50 µs, 10 kHz switching, an M8 four-pin connector and IP65 protection support integration near the label path.

Infrared label fork sensor with 3 mm opening, NPN output, two-point/dynamic teach-in, 10 kHz switching and M8 connector.

Key Features

Infrared LED optical label detection

3 mm fork opening; 42 mm fork depth

Minimum label size and gap 2 mm, depending on label thickness

Plus/minus buttons and cable input for setup

Two-point and dynamic teach-in

NPN output with selectable light/dark switching

Response ≤50 µs; 10 kHz switching

20 mA without load; 20 ms initialization

M8 four-pin male connector

Glass-fiber-reinforced PA housing; IP65

Technical Specification Matrix

Parameter	Value
Functional principle	Optical detection principle
Housing form	Fork shaped
Fork width	3 mm
Fork depth	42 mm
Label detection	Supported
Minimum detectable object	Label size / gap between labels: 2 mm, depending on label thickness
Adjustment	Plus/minus buttons and cable: teach-in, sensitivity and light/dark switching
Teach-in mode	2-point and dynamic teach-in
Power supply	10–30 V DC
Residual ripple	<10%; remain within supply-voltage tolerance
Current consumption	20 mA without load
Initialization time	20 ms
Switching output	NPN
Switching mode	Light/dark switching, selectable via buttons
Switching frequency	10 kHz
Response time	≤50 µs
Output current	100 mA
Connection	Male connector M8, 4-pin
Circuit protection	Supply reverse-polarity protection; Q short-circuit protection; interference pulse suppression
Protection class	III; reference voltage 50 V DC
Housing material	PA, glass-fiber reinforced
IP rating	IP65
Operating temperature	−20 to +60 °C
Storage temperature	−30 to +80 °C
Shock resistance	EN 60068-2-27
MTTFD	97 years
Diagnostic coverage DCavg	0%
UL file	NRKH.E191603
Light source	Infrared LED
Response stability	±20 µs
Jitter	40 µs
Ambient light immunity	≤10,000 lx
Dimensions L x W x H (cm)	6.43 x 1 x 2.5
Physical Weight (kg)	0.036
External teach-in input	Teach: U < (supply − 6 V); Run: U > (supply − 5 V)
Geometry basis	Manufacturer product W/H/D; weight approximately 36 g

Parameter

Value

Functional principle

Optical detection principle

Housing form

Fork shaped

Fork width

3 mm

Fork depth

42 mm

Label detection

Supported

Minimum detectable object

Label size / gap between labels: 2 mm, depending on label thickness

Adjustment

Plus/minus buttons and cable: teach-in, sensitivity and light/dark switching

Teach-in mode

2-point and dynamic teach-in

Power supply

10–30 V DC

Residual ripple

<10%; remain within supply-voltage tolerance

Current consumption

20 mA without load

Initialization time

20 ms

Switching output

NPN

Switching mode

Light/dark switching, selectable via buttons

Switching frequency

10 kHz

Response time

≤50 µs

Output current

100 mA

Connection

Male connector M8, 4-pin

Circuit protection

Supply reverse-polarity protection; Q short-circuit protection; interference pulse suppression

Protection class

III; reference voltage 50 V DC

Housing material

PA, glass-fiber reinforced

IP rating

IP65

Operating temperature

−20 to +60 °C

Storage temperature

−30 to +80 °C

Shock resistance

EN 60068-2-27

MTTFD

97 years

Diagnostic coverage DCavg

UL file

NRKH.E191603

Light source

Infrared LED

Response stability

±20 µs

Jitter

40 µs

Ambient light immunity

≤10,000 lx

Dimensions L x W x H (cm)

6.43 x 1 x 2.5

Physical Weight (kg)

0.036

External teach-in input

Teach: U < (supply − 6 V); Run: U > (supply − 5 V)

Geometry basis

Manufacturer product W/H/D; weight approximately 36 g

Industrial Applications

1. Registering labels for dispensing

A label dispenser can guide its web through the 3 mm fork and use each label-to-liner transition as a registration input. The infrared path evaluates optical contrast, while two-point or dynamic teach-in sets the threshold for the material. The stated 2 mm minimum label size and gap depend on label thickness.

Problem Solved

A transition signal identifies the label boundary for the machine controller, helping coordinate web stopping and dispensing after the actual label and liner contrast have been qualified.

Infrared Teach-in 3 mm fork

2. Counting labels during roll preparation

A roll preparation station can pass the label web through the fork and count discrete changes between labels and their gaps. The NPN output provides switching events to compatible machine inputs. The 10 kHz switching frequency and response of no more than 50 µs define the available timing for separated transitions.

Problem Solved

Counting qualified label transitions gives the winding controller a quantity input for preparing rolls, allowing the machine sequence to compare the accumulated total with its target.

Label detection NPN 10 kHz

3. Checking opaque strip continuity

A strip feeder can route material through the 3 mm fork opening so an intact strip normally blocks the infrared path. A break or runout restores received light and changes the selected light/dark output state. The M8 four-pin connection carries the signal to compatible controls, and IP65 protection supports machine mounting.

Problem Solved

A sustained change of optical state identifies missing material at the monitored point, allowing the controller to coordinate the feed sequence after detecting a strip break or runout.

Light/dark switching M8 connector Material continuity