Instrumentation Monthly Test | Measurement | Control
Due to their durability, versatility and reliability, non-contact sensors are used throughout industry. Alex Sparks from Gill Sensors takes a look into the technology, the features, the benefits and the applications…
Unlike sensors such as limit switches that require physical contact between the object to be detected and the sensor, inductive sensors enable non-contact detection, offering benefits to many industrial applications. Based in Hampshire, Gill Sensors designs, manufactures and supplies both standard and customised induction position sensors, with its latest solutions answering market demands for robust, versatile and cost-effective sensors suitable for even the most demanding industrial applications. In fact, the company’s patented Blade range is regarded as the new generation of non-contact sensors. Gill Sensors is well known in the automotive industry, and its Blade sensors have already been installed in numerous applications – including pedal, suspension and pneumatics.
Some industrial companies are choosing to move away from linear displacement sensors as they are unable to withstand harsh and often uncompromising industrial environments, and may need to be regularly replaced. This is where the new Blade range steps in.
New solutions
The Blade range features Gill’s patented induction technology principle and represents a significant breakthrough in position sensing. There are four products within the series – the Blade20, Blade25, Blade60 and Blade360 – which are being selected by design engineers worldwide.
Being solid state sensors, they have no moving parts and so have an unlimited mechanical life, offering a fit and forget solution in many applications where access can be difficult for replacement. A typical example is the installation of Blade25 sensors for pedal positioning on cleaning and electronic utility vehicles. Once installed it was vital that they could function reliably despite the dirt and vibrations of the vehicles, as not only would it affect the functionality of the vehicles but, due to where they had to be positioned, they would have been difficult to replace.
For use on the factory floor and in some test environments where there is often dirt, water, oil and other harsh chemicals, induction sensors have enormous advantages over optical detection methods as they are sealed and can withstand the harsh environments. They are protected from ingress of dirt and liquids and so have a greater flexibility for use in a wider range of applications. The Blade sensors are currently used for sensing the position of blade cutters in tobacco manufacturing and measuring the position of mould tools in injection moulding machines, amongst other industrial applications.
Advantages
Another advantage of non-contact sensors is that they are unaffected by temperature and so are able to work in temperatures ranging from -40°C to well-over 100°C, and a typical example of this is the new Blade20. This is a single product that allows the measurement of linear and shallow-arc motion as well as long-stroke measurement with a single micro sensor. With a fast update rate for quick positional feedback, it is suitable for a wide range of applications that require fast and accurate position measurement in a dusty or dirty environment. This includes many applications where the sensors need to withstand submersion in fluids and hot oils, as well as pressure washing when tests are complete.
As proximity switches detect without physical contact, there is no damage, accidental or otherwise, to the sensor or object being detected. This non-contact also means that, for all sensors, there is no mechanical wear through use, and so the sensors provide excellent long-term reliability without the need for short term servicing and re-calibration.
Performance
In terms of performance, non-contact sensors offer a fast response and so can be used to provide accurate real-time data. The Blade20 has core electronics that are 40% smaller than the previous generation and the latest technology offers 12-bit resolution capable of data sampling at speeds up to 15 KHz. This high-speed data sampling is ideal for applications where quick transitions need to be monitored. The automotive industry is one of the prime beneficiaries of this type of technology as the product is currently offered with 0.5-4.5V and 0.5-10V outputs, and a new 4-20mA variant is about to be launched.
To assist engineers in retro-fit applications, this sensor features a two-part modular construction, enabling the metal mounting section to be rapidly customised at the factory to suit exacting customer requirements without extensive re-engineering of the product.
Similar to the Blade20, Blade25 is a small, light, robust, low cost sensor complete with on-board processing. Like all in the range, it is a solid-state inductive position sensor and has a configurable 25mm measurement zone, capable of monitoring 25mm linear and 90° shallow-arc movement.
Other sensors in the range include the versatile Blade360, with full 360° measurements, that has been installed on refuse collection trucks to detect the rotational measurement of the bin lifts.
Customised solutions
As well as providing standard, off the shelf solutions, the company has a highly experienced in-house design team at Gill Research and Development. Here, engineers are able to design customised solutions for specific applications. Gill Sensors also has the facilities to deliver short production runs through to volume production.
