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What is a Photoelectric Sensor?

Posted July 07, 2019 12:01 AM by ahorner_22

Photoelectric sensors are able to detect objects using a light transmitter and a photoelectric receiver. These sensors can assess their surroundings and process the distance of an object and recognize if the object is nearby or absent. These systems detect a change in light instantly and can be incorporated into a variety of equipment. There are three main ways photoelectric sensors utilize target detection; through-beam, retro-reflective, and proximity or diffused mode.

Through-beams are the most accurate type of photoelectric sensors. The transmitter and receiver are placed apart from each other with one containing the light emitter and the other housing the receiver. If an object breaks that shared light between the two systems, the machine will sense a disturbance and change its process.

Reflective Sensors are less costly than a through-beam, but their accuracy is slightly less than through-beam sensors. The transmitter and receiver use a reflector to bounce light back from the transmitter to receiver. When an object is detected, it will interrupt the reflective light from the transmitter, and that system will be alerted and respond accordingly.

Proximity sensors use electromagnetic beams to detect when an object is close in relation to the device’s surroundings. In this device, the light source and receiver are inside the same housing unit. The transmitter must reflect off the object to align with the receiver. This system will detect an object when the receiver acknowledges the transmitted derivation.

Photoelectric sensors can help machines sense potential danger and immediately shut done an operation. Each sensor has its own advantages in a given situation. Photoelectrical sensors are becoming increasingly relied upon as manufacturing practices become more automated.

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#1

Re: What is a Photoelectric Sensor?

07/08/2019 9:11 AM

Friend,

Retroreflective photoelectric sensors have the transmitter and receiver within the same housing, a point that was not clear. In some cases they can detect the beam's reflection from a very shiny surface, such as polished metal or even tape, but usually they require a reflector mounted on a surface. The normal mode of detection is to interrupt the reflected beam, but occasionally a shiny object will be unseen because it reflects a sufficient amount of light (in some applications the sensor can be mounted without a reflector and the reflection from a shiny object becomes the signal that is to be recognized).

All light is a form of electromagnetic radiation, so the post should not imply that only proximity sensors use this.

In addition to the good information in the OP, photoelectric sensors come in a wide variety of ranges, with some using polarized light while others do not, and some even use laser beams or pulsed beams (such as used in light curtains).

Critical to proper use of photoelectric sensors is their mounting and alignment.

--JMM

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Re: What is a Photoelectric Sensor?

07/08/2019 2:58 PM

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