Photoelectric Sensors

Photoelectric sensors detect and measure physical objects or quantities by emitting a field or beam of electromagnetic radiation, an object is detected by measuring alterations in the return signal. There are 3 main types of photoelectric sensors which provide reliable detection, these are through-beam, retro-reflective and diffuse. The basic function of each is to detect the presence or absence of objects or measure the distance to the object.

Through-beam Sensors

Through-beam sensors (aka thru-beam) rely on two separate housings, one for the transmitter and one for the receiver, with the transmitter providing a continuous beam of light to the receiver. Each time an object passes through the beam this interrupts the signal between the transmitter and receiver, which in turn causes the receiver to send an electrical signal to the output. Through-beam sensors are suited to long-distance sensing and are capable of detecting almost any object, irrespective of colour or angular motion.

Retro-reflective Sensors

Retro-reflective photoelectric sensors (retroreflective) have both the transmitter and receiver contained within the same housing but require a reflector opposite to the sensor. The reflector bounces the light beam back to the transmitter until an object breaks the beam. Objects which are highly reflective such as aluminium require sensors with polarising filters. The filter allows the sensor to acknowledge that the reflected light from reflecting materials is different from the reflector.

Diffuse Sensors

Diffuse sensors (proximity sensor) are easier to install as only one device has to be mounted. This is because the transmitter and receiver are contained within one housing. Diffuse sensors use the reflection from the target object within a predetermined sensing range. The transmitter sends out a continuous beam of light, once this hits the target it is diffused in all directions, a part of this light is reflected back and recognised by the receiver, the receiver then sends an electrical signal to the output.

A special type of diffused mode is background suppression which enables the user to precisely control the sensing range. A diffuse mode sensor with background suppression is less sensitive to the target colour. They can also use a visible red light or infrared light sources.


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Description Price Sensor Style Detection Type Detection Range Output Type Electrical Connection Maximum AC Voltage Maximum DC Voltage Terminal Type Light Source IP Rating Maximum Current Interface Response Time Housing Material
RS Stock No. 859-3386
Mfr. Part No.MOFR-M12-5
TWD5,666.00
Each
units
Barrel Through Beam (Receiver) - NPN/PNP 15m Cable - 8V - LED IP66, IP67 11 mA - - PC
RS Stock No. 188-5201
Mfr. Part No.PD30CTD02PAWE
TWD1,408.00
Each
units
Miniature Diffuse-Reflective 200 mm PNP NO/NC Cable - 30V Cable - IP67 25 mA - 0.5 (On-Off) ms ABS
RS Stock No. 857-3234
Mfr. Part No.PD30CND10PPM5RT
TWD3,188.00
Each
units
Block Diffuse Maximum of 1 m PNP 4-Pin M8 Connector - 30V M8 LED IP67 30 mA - 0.5 ms ABS
RS Stock No. 188-5213
Mfr. Part No.PA18CAT20PAM1SA
TWD1,510.00
Each
units
Miniature Through-Beam 20 m PNP NO/NC M12 x 4 Pin Connector - 30V M12 LED IP67, IP69K 25 mA - 1 (On-Off) ms ABS
RS Stock No. 188-5215
Mfr. Part No.PH18CND10PAM1SA
TWD1,470.00
Each
units
Miniature Diffuse-Reflective 1 m PNP NO/NC M12 x 4 Pin Connector - 30V M12 LED IP67, IP69K 25 mA - 1 (On-Off) ms ABS
RS Stock No. 188-5211
Mfr. Part No.PA18CAT20M1
TWD982.00
Each
units
Miniature Through-Beam 20 m - M12 x 4 Pin Connector - 30V M12 LED IP67, IP69K 25 mA - 1 (On-Off) ms ABS
RS Stock No. 188-5218
Mfr. Part No.PH18CNT20PAM1SA
TWD1,522.00
Each
units
Miniature Through-Beam 20 m PNP NO/NC M12 x 4 Pin Connector - 30V M12 - IP67, IP69K 25 mA - 1 (On-Off) ms ABS
RS Stock No. 859-3235
Mfr. Part No.S142ARNN024
TWD12,666.00
Each
units
Block - - NPN/PNP - - 24V - LED IP20 - - 20 (ON) ms, 30 (OFF) ms NORYL SE1
RS Stock No. 188-5208
Mfr. Part No.ET1820-1
TWD2,581.00
Each
units
Barrel Through-Beam 20 m - M12 x 1 Connector - 40V M12 - IP67 20 mA - 1.6 (On Typ.) ms, 4.2 (Off Typ.) ms Brass
RS Stock No. 857-3503
Mfr. Part No.PA18CLD04TOSA
TWD4,778.00
Each
units
Barrel Diffuse Maximum of 400 mm Relay Cable 250V - - LED IP67 10 mA - 20 (ON) ms, 30 (OFF) ms PBTP
RS Stock No. 857-3225
Mfr. Part No.PC50CNR10BA
TWD6,148.00
Each
units
Block Retroreflective Maximum of 10 m NPN/PNP Cable - 30V - LED IP67 40 mA - 1 ms ABS/PC
RS Stock No. 188-5221
Mfr. Part No.PC50CNT20BAM1
TWD3,366.00
Each
units
Block Through-Beam 20 m PNP/NPN NO/NC M12 x 1 Connector - 30V M12 - IP67 50 mA - 1 (On-Off) ms PC/ABS
RS Stock No. 857-7517
Mfr. Part No.EO1804PPAS-1
TWD4,225.00
Each
units
Barrel Diffuse Maximum of 400 mm PNP 4-Pin M12 Connector - 40V - LED IP67 20 mA - 3.2 (ON) ms, 5 (OFF) ms Metal
RS Stock No. 859-3301
Mfr. Part No.MOFT20-M12-5
TWD6,740.00
Each
units
Barrel Through Beam (Emitter) 20 m NPN/PNP Cable - 3V - LED IP66, IP67 15 mA - - PC
RS Stock No. 859-3406
Mfr. Part No.PE12CNT15
TWD2,373.00
Each
units
Barrel Through Beam (Emitter) Maximum of 15 m - 3-Wire Cable 5m - 30V - LED IP67 ≤20 mA - 3.5 (OFF) ms, 6.5 (ON) ms PC
RS Stock No. 188-5202
Mfr. Part No.PD30ETR60PAM5SA
TWD3,678.00
Each
units
Miniature Retro-Reflective 6 m PNP NO/NC M8 x 4 Pin Connector - 30V M8 - IP68, IP69K 25 mA - 0.5 (On-Off) ms AISI316L, Stainless Steel
RS Stock No. 859-3024
Mfr. Part No.ET1820PPAS-1
TWD4,716.00
Each
units
Barrel Through Beam (Receiver) 20 m PNP M12 Connector - 40V M12 LED IP67 12 mA - 1.6 (ON) ms, 4.2 (OFF) ms Nickel Plated Brass
RS Stock No. 188-5195
Mfr. Part No.PD30CNG02PPM5RT
TWD2,586.00
Each
units
Miniature Retro-Reflective 2 m PNP NO/NC M8 x 4 Pin Connector - 30V M8 LED IP67 30 mA - 0.5 (On-Off) ms ABS
RS Stock No. 857-3174
Mfr. Part No.PMP12RI
TWD7,222.00
Each
units
Block Retroreflective Maximum of 12 m - 5-Terminal Screw 240V 240V NPT LED IP67 - - 20 (ON) ms, 30 (OFF) ms ABS/PC
RS Stock No. 188-5210
Mfr. Part No.PA18CAR65PAM1SA
TWD1,363.00
Each
units
Miniature Retro-Reflective 6.5 m PNP NO/NC M12 x 4 Pin Connector - 30V M12 LED IP67, IP69K 25 mA - 1 (On-Off) ms ABS