When RAE Systems Inc. builds its wireless sensors, it needs to connect the sensors into a network that can integrate the data and present a complete picture for customers. “We do radiation and hazardous chemical sensing and we wanted a delivery system for sensor information,” says Peter Fuhr, chief scientist at RAE Systems Inc., in Sunnyvale, Calif. “Our sensors go to first responders for situations such as harbor detection.”
Because the sensors are distributed across a wide area, RAE turned to Ember Corp., a Boston wireless networking vendor, for embedded intelligence that can be programmed centrally. “We use Ember reference designs in our modules. One of the beauties of the design is that the modules are able to talk very nicely with each other,” says Fuhr. “From our perspective, it’s transparent. We don’t have to do any programming.” He notes that RAE designers are familiar with sensors, but don’t know much about networking protocol. The embedded technology from Ember lets the engineers set up a coordinated network of sensor data without actually building a network.
Hey, I’m here
Ember executives note that the embedded intelligence allows customers to disperse the sensors, then activate them and control them through a network. “You take a bunch of sensors, put them on the shop floor and these devices will power up and self-discover themselves,” says Venkat Bahl, Ember vice president of marketing. “One wakes up and says, ‘I’m a temperature sensor.’ And it hears the guys around it and in the network as they wake up and advertise what they are,” explains Bahl. This embedded intelligence incorporates three of the emerging trends in embedded technology: open standards, networking and wireless technologies, says Bahl.
At Wind River Systems Inc., an Alameda, Calif.-based embedded software provider, Marc Serughetti points to several other emerging trends. “One trend is toward hard real-time performance. Another is that we can now determine how much software to put on a device. [Unlike personal computers, embedded devices contain limited memory and processing power. Embedded developers must determine just the right amount of software to include for the function, and no more.] In conjunction, we have development tools such as compilers, debuggers and visualization tools,” says Serughetti, who heads up automotive, industrial, aerospace and defense markets at the firm.
Serughetti notes that embedded functionality goes back into the Information Technology (IT) backbone of the automation systems as well. “We have middleware capabilities that include IP (Internet Protocol) technology, graphics libraries, security protocol and Web Services.”
Embedded intelligence is also available to help integrate the control of devices as well as the data from devices. “We focus on connectivity in three areas. One is the control network, which can be either traditional or Ethernet. A second area of connectivity is the connection of the device to the enterprise. We can use Web Services or OPC (an open connectivity standard) if customers want to access the device at the enterprise level.” Serughetti notes that users can also modify the tags at the enterprise level, thus tuning the automation systems using OPC. The third area of connectivity is a small local interface. This gives plant-floor personnel connectivity to the device through a keyboard, mouse or wireless human-machine interface (HMI).
Embedded software is used widely to help build networks for real-time control and data collection. “In a lot of power applications, you’re doing a sequence of events. You’re capturing all the breakers when lightning occurs and you’re seeing what the data does in a millisecond—one thousandth of a second,” explains Connie Chick, business manger for the controller group at GE Fanuc Embedded Systems, in Huntsville, Ala. Obviously, a human being cannot react in a millisecond. “So the embedded technology will look at the data and see what needs to be re-routed,” says Chick. With the embedded software in the network, the controller can be told how to re-route in the event of a failure.
According to Chick, the embedded software allows end-users to do programming using function blocks. “You can do it like a Lego set, or you can do it in C code if that’s simpler,” says Chick. She notes that intelligence is embedded down to the input/output (I/O) itself. “Intelligence is being added everywhere because chips are getting cheaper. You now have intelligence in PLCs (programmable logic controllers), power supplies and I/Os.”
One of the biggest advances in embedded software is the proliferation of open standards. One example is Windows CE, a variation of Microsoft’s Windows operating system that is optimized for devices with minimal storage, and is well suited for embedded systems. “Our new line is based on open standards all the way down to the controller,” notes Chick. “Our whole operating system is on Windows CE in some areas where you need visualization.” The open standards allow different types of applications to connect to the network and communicate with each other.
Trade-offs
The move to open standards is happening throughout the world of embedded technology. “We are embedding more features and functionality, and we’re using more open operating systems such as Windows CE, and now we’re even exploring Linux,” says John Baier, director of software architecture at Rockwell Automation Inc., in Milwaukee. “We’re building the functionality into the control system.” He notes that there is some trade-off when everything is built on open standards. “The closed systems have more real-time capability,” says Baier. “The open systems are not as good for real time, but they allow us access to more software.”
Real-time control and data acquisition is also a strong trend. “We’re seeing an extension in the use of embedded controls—with real-time control embedded in the system,” says Larry Komarek, automation product manager at Phoenix Contact Inc., in Harrisburg, Pa. He notes that with PLCs getting smaller, the intelligence is sometimes embedded in other devices. He also notes that manufacturers are switching to more open systems such as Windows CE. “It’s a natural progression to open software based at the control,” says Komarek. “CE is taking over the functions, replacing medium-size personal computers (PCs).”
One benefit, Komarek notes, is that one hardware device is controlling more functions, meaning that integration time is reduced. “There is some integration that is required, but it’s open, and that standard networking allows for more distribution.” He also observes that changes can be made more easily in the system without changing out the PLCs, because the embedded chip can be reapportioned and re-programmed, and the microprocessor is doing the control. “There’s lifetime savings in that,” says Komarek.
Flexibility
Open standards allow the control network to incorporate both legacy controls and new controls. “As for the PLCs, there are a lot of new devices that have their own controls inside,” says Paul Ruland, PLC and I/O product manager at AutomationDirect, in Cumming, Ga. “All of the control programmable logic is in the PLC and the devices are exchanging signals in and out.” He notes that in the new PLCs, the software can be used by different controllers and CPUs. This gives the manufacturer flexibility when changing products in the plant. “You can take the program you used for your previous product and put it into the controller for the new product.”
The ability to monitor—and even control—plant operations from afar is also becoming more important to manufacturers. “You now have distributed monitoring running on Windows CE,” says Craig Resnick, research director at ARC Advisory Group Inc., in Dedham, Mass. “You have the power to look at remote transmitters located way up in the bowels of the plant.”
Embedded technology also allows manufacturers to bring together different types of controls into one monitoring platform. “The other area is embedded programmable automation controllers (PACs) that meld PLCs with PCs for multi-discipline control,” says Resnick. “Instead of getting just PLC data, you’re getting motion control and process control in one database, with one HMI. You can combine a number of systems—PC, motion, PLC—all in one platform.”
Many needs
Manufacturers have multiple needs for their automation systems. They want to connect data from disparate devices, both wireless and wired, and they want to view—in some cases even control—their automation system from afar. Manufacturers expect their vendors to create intelligent systems to serve all needs. The vendors have responded by embedding intelligence into control devices, automation platforms, PCs and Web Services middleware. This allows manufacturers to build their systems with flexibility and connectivity.
See sidebar to this article: Connecting Machine Controls Over the Internet
