Industrial sensors come in various types, with interesting differences between what they can do and how they are used. The three main types are linear, rotary and tilt sensors. Some sensors are also what is called “intrinsically safe” – that is they can be used in atmospheres that are volatile or hazardous. Here’s an overview […]
Industrial sensors come in various types, with interesting differences between what they can do and how they are used. The three main types are linear, rotary and tilt sensors.
Some sensors are also what is called “intrinsically safe” – that is they can be used in atmospheres that are volatile or hazardous. Here’s an overview of what these types of sensors do, and how they are used.
Accuracy Results from Quality
To give accurate results, sensors need to be manufactured to very high standards. The casing materials need to be capable of withstanding whatever environment the sensor is operating in, even if the sensor is submerged in salt water for extended periods. Superb sensing technology design from the likes of Positek.com is required to produce a product that combines exceptional accuracy with robust operation and long life..
Linear Position Sensors
Linear sensors are able to pickup the linear position of an item or device and as a result measure its movement . The sensor then converts the measurement into a digital signal. This is either passed to a motion controller which takes action to adjust the position if required,or sent to a control system or display.
Linear sensors can come in all kinds of outer casings and are sometimes built to order if a particular outer packaging is required. Hydraulic cylinder position sensors have the advantage of being compact and robust, and not needing any magnetic components.
Linear Sensors in Industry, Mining and Marine Applications
Heavy duty sensors are used for environments where there is vibration. However some industrial applications produce large amounts of dust or flammable gases. That means industries such as mining require “intrinsically safe” equipment that will not cause sparks or static while operating. The stakes are extremely high, as unsafe equipment could cause an explosion with possible loss of life. Intrinsically safe sensors won’t emit any spark that could ignite a gas or other substance. They are installed with a three part amplifier that is galvanically isolated.
Obviously, when linear sensors are going to be used underwater, they are made of stainless steel that is marine grade and will withstand the effects of saltwater. Many marine industries use these sensors, including offshore oil drilling platforms and rigs, and water treatment plants. They can be used down to depths of 3,500m, so are found in a wide variety of sea, lake and river locations.
Rotary sensors differ from linear sensors in that they measure angles to a high degree of precision. This data can be translated into very accurate position feedback. Rotary sensors are found in all kinds of high technology applications, from medicine to the army, to space and deep sea operations. Miniature and slimline versions are available for use with very compact applications, and some engineers buy a flat version that they can integrate into their own application.
Some of the industrial rotary sensors are also intrinsically safe, with specific labelling and number classifications, according to whether they are safe for dust, gas, or other hazards. Again, they are usually designed for use with a galvanic transformer.
Like the linear sensors, they come in versions that can be used beneath the sea and will stand depths of up to 3,500 metres. They are often used on Remotely Operated Vessels (ROVs) that are employed to survey ship’s hulls and carry out other subsea work. These marine rotary sensors have to be completely sealed so that they can work for extended periods under water.
These are also known as “inclinometers”. They measure the degree of slope and are used in a diverse range of applications, from off-shore installations such as drilling platforms, to submarines, to measuring the degree of tilt when cranes are in use.
The best quality tilt sensors are made from corrosion-resistant metal, and can therefore also be used in outdoor positions or under water. The newest models are contactless – they don’t need to make contact with any material in order to sense the angle of tilt, so they aren’t subject to wear and tear, and are very robust and long lasting as a result.
Tilt sensors, like the rotary and linear ones, are available in intrinsically safe models. You can imagine, in the example of the crane, that it might be operating on a demolition site with large amounts of potentially flammable dust. The same goes for tipper trucks operating near mines. The angle of tip needs to be measured but it’s necessary to have an intrinsically safe tilt sensor that will never emit a spark strong enough to ignite the dust.