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 factors and functions, their technical capabilities are beginning to change as suppliers respond to customer demands for more information to improve device reliability and process productivity.
The idea that information from actuators, including motors and drives, can be used to improve the operation of those devices is not a new one. After all, control systems have been monitoring and managing production systems for years. But by using actuators with the ability to connect to the Internet, it’s easier to see how an individual device is operating from outside the production system, separate from the mass of process information. It’s one of many next steps on the road to what is being described as smart manufacturing.
Although much of the focus now is on using Internet-ready actuators for predictive maintenance to reduce production downtime, most experts say even greater benefits will accrue in the future from being able to optimize the functioning of a production process and its individual components.
“In the past, it was difficult to gauge how an individual device was functioning or why it was failing because data was limited or maybe not available at all,” explains Rich Mintz, marketing manager for low-voltage motors and drives at Siemens. “Now, if an actuator is compatible with Ethernet, it may be able to have its own IP address, so data could be viewed on a web page. But we’re starting to see diagnostic data on another layer, a platform for viewing the data that’s being generated by the device and that you can use for analysis, whether it’s detecting what caused a fault or predicting faults before they can occur.”
This diagnostic data can exist outside the proprietary process data—sometimes in the cloud—so that third parties can also help with data analytics while maintaining security. “It’s condition monitoring with a purpose,” Mintz says. “The point is to turn data into information: I’m overheating because this is happening and here’s what you need to do to fix it.”
The goal of making actuators with Internet of Things (IoT) connections is to find ways to help customers with their process problems, notes Ranjani Balasubramaniam, director of large drives strategies and programs at Siemens. “Since additional capabilities are now available, we need to make sure the benefits are well understood by the customer.”
She cites industries that deploy large motors as a critical part in their processes, such as mining, oil and gas production, paper and power generation, as most likely to benefit from IoT-ready actuators. “This is not only because these motors consume a great deal of electricity, but because downtime can be extremely expensive, both in terms of lost production and the difficulty in restoring operations, especially in remote locations.”
But even a small motor can play a critical role in a process. “If how a device is functioning affects product quality, process continuity, redundancy or safety, then it’s worthwhile to invest in getting more information about how it’s operating,” Balasubramaniam says.
Like many other automation suppliers, Siemens has begun to offer device-monitoring services for its customers, in its case monitoring mobile mining equipment using lifetime analytics. “We’re able to help customers visualize data from their machines, so they’re better able to understand what’s happening and why,” Balasubramaniam adds.
Ethernet simplifies connectivity
Though Internet-ready devices don’t usually look much different than the traditional versions, they do require a physical port to allow a device to make an Ethernet connection. These devices also often have an embedded Ethernet-based protocol that makes it easier to connect them to a network or the cloud. Some suppliers are also working to develop wireless interfaces.
You can make this kind of connection from a traditional fieldbus network, but it’s much more difficult technically. Another Ethernet benefit is that it’s capable of transmitting larger amounts of data than traditional fieldbus.
“If you know how healthy the devices in your production process are, you can take proactive steps to minimize downtime,” says Nuzha Yakoob, senior product manager for electric automation at Festo. “That’s the whole purpose for having Internet-ready actuators: so that you can monitor vibrations, temperatures, rotor status or any number of other conditions that could affect equipment operations.”
Ethernet connections—as opposed to closed systems like CANopen or DeviceNet—make it easier to exchange data and monitor production equipment remotely over a wide area network or through the cloud, Yakoob explains. “Companies in the petrochemical industry, for example, are finding Ethernet extremely useful for monitoring process and production systems, which are often spread over large geographical areas,” she says. “The ability to share information between facilities or with the supply chain is even more important for companies that operate globally. Factors like these are driving the adoption of Internet- and Ethernet-ready devices.”
One of the advantages of IoT-ready controllers is two-way data exchange. “This allows you to share data to a SCADA system or the cloud, but it also makes it easy to push data down to electric or pneumatic devices for parameterization or configuration,” Yakoob says. “At Festo, we use the open standards protocol IO-Link, which can push data into IO-Link master devices that are employed on various machines to regulate pressure, monitor temperatures and sense positions or other values. We also use the OPC UA open standard for data exchange. These standards simplify machine communications.”
Sensors as a bridge
While electromechanical and electronic devices have been relatively easy to modify to accommodate Ethernet and Internet communications, pneumatic actuators must find ways to overcome the restrictions placed on them by traditional standards.
“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.”
