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What gets your blood flowing? If you're an industrial network, then cables and wires are the arteries, electricity is the fuel, and digital data are the nerve impulses from the enterprising brain.
So, what centrally located device pushes and coordinates the rhythms of this circulatory network and the nervous system it supports? Where's the heart?Similar to so many critical, taken-for-granted workhorses, it's hiding in plain sight. The heart of any industrial network is, of course, the central processing units (CPUs) in its equipment and subsystems. These ever-faster, more powerful, less costly and more varied microprocessors perform almost infinitely more calculations, run more sophisticated software, and exchange information over networks managed by Ethernet switches and routers, which have their own onboard chips.
It's no stretch to say that microprocessors have helped industrial connectivity to evolve over the past 25 years from hardwiring to fieldbuses to Ethernet to wireless, and onward to Internet-enabled monitoring and the recent emergence of cloud-based services and virtualized computing on fewer servers.
"When you think about it, microprocessors and software allow all parts of our networks to function," says Corey Heckman, automation manager at Control Systems 21, a system integrator in Dillsburg, Pa. "Without them, we'd have to try to use relays, big logic panels and hardwiring. It would be a nightmare because all of our projects would be unworkable."
Control Systems 21 implements SCADA and PC-based devices for process control systems, mostly in industrial and municipal water/wastewater systems. To bring in required signals and data, its networks transition rapidly from wired to wireless hardware and back again, and their communications methods also move from serial to wireless protocols to virtual private networks (VPNs). As a result, Control Systems 21's often far-flung networks use serial and Ethernet radios, cellular communications, and other wireless devices.
For example, for a mid-sized city to add wastewater metering to its municipal water system, Heckman's team is networking all of the system's pumps, PLCs, digital video recorders (DVRs) and other components at about 25 different sites. These locations include wells with high-level monitors, inputs for water from other systems, a reservoir with booster pumps, and data-collection metering for the wastewater system. The main network is using Modbus TCP/IP with Ethernet switches, but its communications also use the Internet for remote video surveillance of stations, VPN tunneling, Phoenix Contact's Trusted Wireless Ethernet (TWE) radios and other components. All of these devices are polled by PCs running Trihedral's VTS SCADA/HMI software. Data from the remote stations comes in via serial UHF licensed or 900 MHz unlicensed radios or VPN tunnels, and an OPC server translates and coordinates this input, so the SCADA/HMI software can analyze and display it.
"I was even able to set up an app, so the city's engineers can monitor the water/wastewater system with Android smartphones," Heckman explains. "Of course, this web-based application also has verification steps and security certificates to make sure that access is secure."
Cellular communications weren't used much on the plant floor in the past, but that's changing as bandwidth increases through the growth of 3G and 4G technologies, reports Rich Harwell, connectivity manager for Eaton's controls and automation group. "Many web-based applications and access to local area networks (LANs) are being enabled by cellular, and so it's going to show up in more machines and industrial settings, too," he says.How Chips Evolve and Help
Although microprocessors have multiplied their capacities and speed many times over, while shrinking in size and cost, it can be harder to understand exactly what this means for industrial networks and their users and applications. Who can really comprehend billions and trillions of calculations flashing along in a microscopic space?
Certainly, the end result and evidence is that useful tools such as Ethernet switches have been popping up, but learning more about microprocessors' internal workings could help convince more potential users of their capabilities and reliability. One often-repeated rule of thumb is that anyone planning a typically longer-lifecycle industrial network should make sure to install enough bandwidth, maybe even Gigabit Ethernet, to handle all the traffic from IT components, mainstream electronics and other devices with shorter lifecycles.
"Microprocessors might be on the lowest layer of the network, but they have a huge influence," says Mike Justice, president of Grid Connect, which manufactures networking products. "For example, when I was at Lantronix about 10 years ago, we introduced X-Port, which was just a simple RJ-45 connector with an Ethernet chip inside. However, it let any serial device communicate via Ethernet, and so GE used it to add multiple networks to control devices for elevators, pneumatic tubes and other applications."
Last month, Grid Connect introduced its gridARM microprocessor architecture to enable 1 Gbps Ethernet at low cost in scales, barcode readers, I/O points, and web-based controllers. "Lots of office devices use Gigabit Ethernet, and so the factory will need it soon to be scalable for the future," Justice adds.
While microprocessors have shrunk and speeded up and done the same for all the devices in which they're embedded, the persistent needs of many applications and users have also caused those chips to adapt and adopt more varied functions. For example, older-generation semiconductors and standard microprocessors were cheap and plentiful, but they didn't have the design flexibility and functions that many device builders needed. So they gave way in many cases to application-specific integrated circuits (ASICs) that were produced in lower volumes by third-party fabricators. That gave users the design-stage flexibility they needed, even though they were typically built to do just one job. More recently developed were field-programmable gate arrays (FPGAs), which are similar to ASICs, but can be programmed by the user for specific tasks after they're manufactured. And, of course, even more flexibility and capacity has been added since then to FPGAs and other systems on a chip (SoCs).