Optical sensors are devices that are designed to control distance and position, determine color and contrast marks, as well as solve other technological problems. Devices are mainly used in industrial equipment.
According to the method of operation, optical sensors are divided into three types.
Devices reflecting from an object are capable of emitting and receiving light that departs from an object located in their coverage area. A certain amount of light is reflected from the target and when it hits the sensor, it sets the corresponding logical level. The size of the response zone largely depends on the type of device, size, color, surface curvature , roughness and other parameters of the object. In their design, the receiver and emitter are present in one housing.
Optical sensors reflecting from the retroreflector receive and emit light that comes from a special reflector, and when an object interrupts the beam, the corresponding signal appears at the output. The scope of such a device depends on the state of the environment that surrounds the sensor and the object (fog, smoke, dust, etc.). In this device, the emitter and receiver are also located in one housing.
The third type includes optical sensors, which have a separate receiver and light source. These elements are installed opposite each other on the same axis. An object falling into the region of the light flux causes its interruption, and at the output, accordingly, the logical level changes.
The light elements of the devices can operate at different wavelengths, which include infrared or visible (laser) light, as well as other indicators of color marks.
In its design, the optical sensor consists of an emitter that generates light in various ranges, as well as a receiver that distinguishes the signal emitted by the first element. Both components of the device are located both in one and in different buildings.
The operation of the instruments is based on a change in optical radiation when an opaque object appears in the coverage area. When the device is turned on, an optical beam is emitted, received through the reflector or reflected from the object.
Then, a digital or
analog signal having a different logic appears at the output of the sensor, which is then used by the actuator or registration circuit.
Fiber optic sensors have different sensitivity zones, which range from a few centimeters to hundreds of meters.
It is most convenient to use diffuse devices that independently operate on the object. For the most part, optical sensors allow you to change the sensitivity settings and indexing of the output status, and self-tuning models are also produced.
Devices on the market are represented by many manufacturers. For example, devices manufactured by AUTONICS are especially popular. They are distinguished by a wide variety, low price and high reliability.