Technical Blog

Positek's Cylinder Position Sensor Technology

Positek's patented inductive non-contact sensor technology used in manufacturing cylinder position sensors are superior to other linear transducers used in hydraulic and pneumatic actuators.

A cylinder position sensor used in hydraulic and pneumatic actuators determines the end stroke and home of the piston head inside the cylinder. The increasing demand for better control and function made cylinder position sensors more relevant in industrial applications such as in hydraulic and pneumatic subsea machines and equipment. There are three common technologies used in designing position sensors for these applications. These are magnetostrictive, variable resistance, and variable inductance position sensors.

Magnetostrictive sensor technology

Magnetostrictive sensing technology has traditionally been used in high-accuracy applications. These sensors consist of a tubular probe made of stainless steel and a permanent magnet assembly usually installed in recessed counter board within the piston. The electronic components of the sensor are typically threaded into an O-ring port behind the cylinder, while the probe is connected to the rod's bore. Magnetostrictive sensor technology uses the principle of â€time of flight" in accurately determining the magnet's position in the least amount of time.

Each sensor manufacturer has a different magnet style with various features such as the hole pattern and many more. Despite the reliability of the technology, magnetostrictive sensors are not mechanically rugged and are susceptible to vibration and shock. What magnetostrictive sensors offer is electrical performance and is most suitable for port-mounted hydraulic and pneumatic cylinder use.

Variable resistance sensors or potentiometers

Potentiometers are considered to be one of the most common types of linear position sensor used today. This type of sensor is chosen when the application is cost-prohibitive, and high accuracy is not a requirement. A potentiometer is typically installed at the rear end cap of the cylinder. Some of the favourable characteristics of a potentiometer include stroke-to-length ratio and the large voltage output. However, a potentiometer easily wears out due to friction. Moreover, the embedded nature of the assembly makes replacements time-consuming and difficult.

Linear Variable Inductance Transducers

An LVIT is a type of linear transducer used in pneumatic and hydraulic cylinder applications, but not as widely recognised as potentiometers and magnetostrictive sensors. An LVIT uses a non-contact technology which has many advantages over other types of sensors. A non-contacting position sensor has better linearity, resolution, and robustness. Another significant advantage of an LVIT is its resistance to shock and vibration which makes it ideal for highly industrial applications.

What kind of cylinder position sensors are offered by Positek?

Positek caters to a range of buyers from different industrial sectors and manufacture cylinder sensors using patented non-contact technology. Positek sensors are unique because unlike conventional linear position sensors, Positek's range of cylinder sensors use an inductive technology which makes each device suitable for even the harshest applications.

Within our range of cylinder position sensors, one of the most popular is the P100 with measurement range options from 0-5mm to 0-800mm. This model also comes with IP65 or IP67 environmental sealing. Positek's non-contact inductive cylinder sensors have longer lifecycles compared to potentiometers and magnetostrictive-type sensors.

Typical applications for cylinder position sensors

Hydraulic and pneumatic actuators make use of the properties of air and fluid to produce mechanical force. Compared with electrically driven machines, hydraulics and pneumatics do not need a power source and are quite robust systems for use in industrial assemblies.

Cylinder position sensors play a vital role in hydraulic and pneumatic functions because these devices provide displacement feedback essential for function control. A typical example of hydraulics is a car brake.

What makes Positek's cylinder position sensors ideal for industrial use?

Industrial applications require rugged and robust devices to withstand various conditions such as underwater pressure, friction, shock, vibration, and extreme temperature. Positek manufactures a range of sensors using non-contact inductive technology suitable for all industrial applications. Our range of sensors comply with intrinsic safety requirements imposed by the mining industry, and we also offer sensors with environmental sealing needed for some sensitive applications.

With over 25 years of experience in manufacturing position sensors, Positek has the expertise and know-how to custom-build a sensor according to your desired dimensions and specifications. If you need customised cylinder position sensors, you can contact our dedicated engineering team to help you with the design process and build the sensor you need in our on-site production facility ready for delivery within a matter of days.

Article published on: 25/03/2019