Internet-Ready Actuators and a World in Motion
Actuators—whether powered by electricity, air or some type of fluid—are an integral part of creating movement in any production process. Long viewed as commodities, with strict limits on form factorsr="ltr" style="margin: 0in 0in 8pt;">
“To put electronics into pneumatic actuators you would have to change their size in terms of length and width, so they would no longer fit the NFPA standards,” explains Mark Densley, head of product management for controls at Aventics.
Makers of pneumatic systems like Aventics are getting around this barrier by using sensors as a bridge to access device data such as speed, velocity or whether cushioning is deteriorating. “Sensors allow us to manipulate data and turn it into something we can interpret and transmit over Ethernet using the OPC UA standard, which provides a universal language for communicating between different machines,” he says.
Maintenance is another challenge that must be overcome in the transition to devices that use electronics, according to Densley. “Workers who are familiar with how pneumatic devices work may not know as much about electronics or control systems,” he says. “It’s up to us as a manufacturer to make it easy.”
Smart pneumatic monitors are able to communicate using many different standards and are completely independent, so they don’t interfere with process control running on fieldbus. Software modules are optimized for typical pneumatic applications, such as pressured air consumption, leakage detection by consumption monitoring and correlation with process information, wear monitoring for actuators and shock absorbers, and counting switching cycles.
“Intelligent pneumatics combine hardware, electronics, software and data,” Densley explains. “While the increasing volume of data transfer will stress controls and IT networks, local data analysis and creation of information can provide a solution. Decentralizing valve electronics, for example, will support modularization and networking.”
Encouraging proper maintenance
Transitioning to IoT could help overcome a perennial problem at many manufacturing sites: the attitude that equipment should be run to failure rather than following proper maintenance practices. “Equipment often isn’t maintained or is subjected to heavier duty use than it was designed for, so that it fails when people don’t expect it,” Densley says. “When Ethernet and the Internet make condition monitoring and predictive maintenance easier, companies will begin to see the advantages because they’ll experience less downtime and greater productivity from their equipment investment.”
Manufacturers usually focus on three priorities when they adopt an IoT architecture: condition monitoring, lifecycle analysis and energy efficiency. “For example, control valves usually have a lifecycle of 140 million cycles. Using web access to monitor cycle counts allows you to predict when the valve will fail,” Densley explains. “The capability to generate this data is built into the valve and the I/O module can transmit the information to an OPC server or a gateway.”
Plant personnel are less interested in knowing exactly what’s going on with the actuator than in how the equipment and the production process are performing, he adds. “With two-position sensing, for example, you can monitor when a cylinder enters the cushioning area and when it leaves. This helps you determine if shock absorbers are wearing, which would tell the operator to use more air in the process.”
It’s not just manufacturers that want to know how well machines are operating. OEMs have a vested interest as well, Densley says. “OEMs make money selling spare parts, but not until the warranty expires. They’re looking at remote monitoring as a way to prevent downtime while a machine is under warranty, because they don’t want to have to pay the cost of fixing it.”