Know your pneumatics – Continuous Position Sensing

26 February, 2018

Modern factories are increasingly using industrial networks to make their sensors and actuators more intelligent and the deployment of smart sensors, such as Continuous Position Sensors (CPS), is certainly the pathway to achieving smart motion control in pneumatic systems. These intelligent devices offer more sophisticated, flexible, effective and efficient factory automation, and ultimately, with two-way data flow, help facilitate what can be defined as a true Industry 4.0 environment.

As one of the three principal building blocks of ‘smart pneumatics’ (along with processors and communications protocols), the latest smart sensors are being developed to bring intelligence to pneumatic motion control and provide the necessary continuous data in what are often challenging or harsh operating conditions.

Smart factories

Most manufacturers have their own ideas and interpretations of ‘smart factories’ and what they can offer. However, a common theme is the need for embedded components to have additional intelligence, thereby enabling machine-to-machine communication and response. All of these ideas eventually come down to more practical aspects such as system architectures and how the multitude of new sensors will communicate via the network.

To appreciate the potential of continuous position sensing, it is best to first consider how they function. CPS use contactless technology to continuously detect the linear position of a piston in its cylinder. The data communicated by the sensor allows monitoring and, when information flows in both directions and actuators are employed, control. The result is the transformation of pneumatically actuated processes from ‘dumb’ to intelligent; meaning that positional data is available, which can enhance monitoring and control, allowing for fast detection of any issues that might cause downtime or potential loss of productivity. The intelligent functionality of smart sensors includes the ability to acquire information and communicate with upper level controllers and/or local networks. Importantly, the quick, precise and high-resolution sensing of the piston magnet is achieved without the need for separate position encoders or additional mechanics, therefore minimising the cost of implementation.

Easy mounting

For cylinders, linear slides and grippers with common T-slot or C-slot dimensions, the latest sensors can be mounted without the need for extra accessories, while mounting on other cylinder types, such as round body, tie-rod and profile cylinders (and cylinders with a dovetail groove), is possible using a simple adaptor. Sensors that can be externally mounted on the cylinder body in this way avoid complicated integration requirements or any drilling of the piston rod itself. This design also facilitates quick and simple sensor maintenance or replacement.

Application benefits

Among the principal benefits of continuous position sensing is the ability to monitor quality and provide process control and support optimisation, especially in tensioning applications such as paper or film processing where quality, repeatability and speed are paramount to profitable operations. Here, the remote reading of data from position sensors allows process deviations to be seen quickly and acted upon, thus keeping processes optimised and supporting predictive maintenance strategies.