The term sensor (as in position sensor) can be quite confusing to any layman, and even engineers may have a difficult time distinguishing the jargon associated with it. In essence, a sensor is also referred to as an encoder, a transmitter, a transducer, and a detector, and they basically refer to the exact same thing.
What makes it even more confusing is the fact that some types of sensors, such as proximity sensors, are not really position sensors, but switches since they only detect the presence or absence of an object. This basically means that these ‘proximity sensors’ only produce a basic digital or on and off output rather than measurement of position. In this guide, we will look only at true position sensors instead of switches. True position sensors will release a signal (often electrical) which is proportional to a measurement path’s position. There are actually different kinds of position sensors available today, so let’s have a look at these different kinds so you can find the right position sensor for your needs.
First, their uses
Position sensors can be used for a variety of applications in both industrial and commercial sectors, from the most complex military and defence applications to simple, inexpensive applications in automation and even in appliances used by consumers. After the measurement of temperature, the measurement of position is the most important property to be measured.
The potentiometer is the most common and popular type of linear position sensor, but there is now a trend towards the use of sensors which are non-contact. Potentiometers can measure a drop in voltage when an electric contact is sliding on a track which is resistive, and this means that the position will be proportional to the output of the voltage. There are linear, rotary, and curvilinear potentiometers, and all of these are compact and lightweight. Potentiometers perform well in gentle and relaxed, low-pressure applications. They can easily wear down in high-pressure or vibration applications, especially when there is dust or sand.
· Capacitive sensor
A capacitive sensor or capacitor is a device where an electrical charge can be accumulated, and it often has an insulator which separates two plates which are conductive. The charge quantity which can be stored by a capacitor can vary depending on the plate’s sizes, the plate’s separation, the permeability of the material, and the percentage of overlap. Capacitive sensors, whilst compact, are not generally chosen when it comes to safety, however.
· Traditional inductive sensor
A traditional inductive sensor can operate on inductive or transformer principles, and these types of position sensors have been in use for more than a century. These sensors are safe as well as reliable, even in tough environments, and they are a go-to-choice when it comes to applications requiring safety. LVDTs or linear variable differential transformers are an example of this type of position sensor, and it consists of three spools of wire, a primary spool, and 2 secondary spools. These types of sensors are highly accurate and robust, and they are also very reliable and can work even in extreme applications and environments.