Unlike other position sensors, a linear position sensor detects linear movement that aids in lab measurements and also in industrial automation. With this integral use, innovators have continued to use new materials in developing this measuring device. Linear technology incorporates internal electronics that allow for its sophisticated functions. Modern linear position sensors are found as feedback devices on the ground, in the air, underground, and underwater. They can now withstand harsh environments with vacuum pressure conditions, extreme temperatures, and exposure to radiation. Indeed, the array of types has expanded so much that it continuously confuses people regarding which sensor to use. This list tries to distinguish each class from one another according to the function it serves.
Eddy current sensors
These are non-contact type sensors that consist of two coils. A moving object influences the first active coil, thus, bringing about eddy currents. Relative motion causes circulating currents or the flow of electrons within the conductor. The second coil completes a circuit for providing temperature compensation regulating the heat produced by the conduction. With this set-up, these devices can be used in dirty environments.
These sensors consist of optical time of flight, optical triangulation, and fibre optic components. They function by using the detection and projection of light. These discover the distance or the absence or presence of an object, by using a light transmitter and a photoelectric receiver. If an object’s movement is difficult to measure due to its environment, photoelectric sensors are recommended for use as these are the most accurate out of all sensors.
In contrast to photoelectric sensors, this detector works by using the detection and projection of sound. They comprise piezoelectric crystals that use high-frequency sound waves to resonate the desired frequency and convert electrical energy into acoustic energy. Usually, these sensors are used to detect liquid levels in tanks.
This type produces a resistance output that is proportional to the object’s position. Linear potentiometers are used for length measurement in many laboratories and as well in industrial applications. The sensors are easy to install and offer precise measurement values even under challenging conditions. However, contamination can potentially enter because of the sliding parts of this device, making effective use more complicated and compromising long-term reliability of measurements.
These sensors are of the non-contact-type that measure the difference in voltage that is applied between the target and the sensor. They are used in both conductive and non-conductive materials, and they are sensitive to environmental parameters like air. These sensors are commonly seen in track pads for laptops.
As seen in this list, linear position sensors offer a wide array of functions. From detecting water levels to measuring the position of various objects under challenging conditions, there is always a type of linear position sensor that is available for use. It is necessary to distinguish which sensor to use based on the application and project specifications.