Some species of sharks must constantly swim to keep water flowing over their gills to stay alive. That same concept also tends to apply to technology — once a technology stops evolving and moving forward, it's on its way to extinction. Fortunately for those responsible for designing and maintaining the pneumatic systems found throughout industrial environments, new sensing and data communications solutions are making pneumatics smarter and simpler to integrate into the Industrial Internet of Things (IIoT). The future of pneumatics will be linked with the expansion of smart sensing technology. Cost-effective sensing and information processing equipment is now becoming part of all types of fluid power equipment, from connectors, tubing, and hoses, to pneumatic cylinders, actuators, and filters.
The latest sensor technologies available for fluid power systems make their predecessors seem unsophisticated by comparison. Once, traditional solenoid valves were operated by simple contactors in an output card. Today, network-enabled devices offer built-in diagnostics sensing for monitoring temperature, voltage, current, and sometimes even cycle counts. These sensors offer a plant's management team an almost overwhelming amount of data that, if used properly, will allow them to revolutionize the way they operate and maintain their facilities’ equipment.
Processors, communications protocols, and the latest smart sensors make up the three main building blocks of “smart pneumatics.” These sensors are being developed to provide continuous data in factory environments that may have challenging or harsh operating conditions. Integrating smart sensors, such as continuous position sensors, into pneumatic systems paves the way for more advanced, effective, and efficient factory automation.
Continuous position sensors employ contactless technology to continuously detect the linear position of a piston in its cylinder. When information flows both ways, the data the sensor produces makes it possible to transform “dumb” pneumatically actuated processes into intelligent ones. These sensors can acquire information and communicate it to upper-level controllers and local networks. Making positional data available enhances monitoring and control, and highlights any issues that could cause downtime or a productivity loss. Best of all, the fast, precise, and high-resolution sensing of the piston magnet doesn't require separate position encoders or additional mechanics, minimizing implementation costs.
One of the biggest advantages that continuous position sensing offers is the ability to support process control and optimization, and monitor quality. For tensioning applications like paper or film processing where quality, repeatability, and speed are essential to profitability, this ability is particularly beneficial. In these applications, the ability to obtain data from remote position sensors lets systems detect and respond to any deviations in the process quickly, so processes are constantly optimized.
Continuous position sensing has advantages for other types of industrial applications as well, such as material handling, small component assembly, machine building, and consumer packaging. These sensors can even take on tasks in the renewable energy industry, such as adjusting the position of solar panels so they can track the Sun. They can be enhanced with upgraded shock, vibration, chemical, moisture, and water ingress resistance to support long-term use in challenging environments.
No extra hardware is needed to mount the latest generation of non-contact position sensors on cylinders, linear slides, and grippers with common T-slot or C-slot dimensions. Other cylinder types, such as round body, tie-rod, and profile cylinders, and those with a dovetail groove require only a simple mounting adapter. When mounted outside the cylinder body, these sensors have no complex integration requirements and don't require drilling the piston rod itself. This design also allows for fast, simple sensor maintenance or replacement.
A study conducted by Accenture and General Electric found that predictive maintenance can generate a reduction in maintenance costs of up to 30 percent, and a drop-in production line downtime due to equipment breakdowns of up to 70 percent. Making machines smarter is essential to implementing a predictive maintenance strategy. By handing management the ability to foresee issues, it gives them the flexibility to plan how to address them rather than simply react to problems as they occur.
The same industrial networks needed to connect production and factory equipment and make them more intelligent also provide the means for communicating vital information about the health of machine components. Early sensor notification of emerging problems allows system operators to investigate, consider, plan, and schedule the required corrective maintenance for a time of low production demand, or when there's little downside to pausing production temporarily.
Consider this example: Pneumatic motion systems are often subject to voltage sags on long wiring runs that may cause valve misfires and quality problems. Without smart pneumatics, maintenance personnel would have no way of diagnosing the cause of the problem unless they plugged in an oscilloscope and monitored the voltage signal when a sag occurred. But if each valve manifold node included voltage sensing, a simple “sweeper” program would allow recording voltage levels across the machine during certain portions of the cycle.
Manufacturing facilities have long used one-way monitoring of sensor data via traditional discrete or analog signals for remote oversight of automated processes. But implementing preventive maintenance strategies requires two-way communications.
The IO-Link protocol offers an optimal solution by supporting two-way communications to receive data and then download a parameter to the device/actuator, which allows for adjusting processes remotely. Introduced in 2008, IO-Link is the first IO technology for sensor and actuator communication to be adopted as an international standard (IEC 61131-9). It allows devices to be integrated in the same way in all commonly used Industrial Ethernet and automation systems, right up to the Enterprise Resource Planning (ERP) level. IO-Link is not a Fieldbus; it simply supports point-to-point communication between field devices and the automation system. Although integrating a network interface down to the lowest field-level device can be expensive, IO-Link is a simple, far less costly system.
Unlocking the power of smart sensors like non-contact position, voltage, temperature, or vibration sensors and many others depends on making diagnostic information more accessible. IO-Link supports cyclic data exchange capabilities so programmers can readily send the information to wherever it's needed, whether that's an operator's computer screen, a signal indicator, or a maintenance request. Sensor and actuator parameters can be changed or calibrated remotely, even while production continues, reducing line shutdowns, stoppages, and cost. Think of the advantages of being able to identify a component that is nearing the end of its expected cycle count so it can be replaced during a planned downtime, rather than during an unplanned line shutdown.
The combination of smart sensors and IO-Link could also be invaluable in predicting cylinder leakage or rod gland failure. With vibration sensors embedded at the right locations, and the tools to communicate that data back to a monitoring system, it would be simple to write a program to conduct and record a simple trend analysis to predict if a leak or gland failure was likely to occur.
The future of pneumatic technology in industrial environments will remain vibrant as long as manufacturing operations and the vendors that serve them remember that they need to keep moving forward in order to avoid falling behind.
This article was written by Tim Faillo, Global Program Manager - Factory Automation, for Parker Hannifin Corporation Pneumatic Division, Richland, MI. For more information, visit here.