Network Devices Need Software Support

Network Hardware Depends on Strong Software to Hold It All Together and Improve Machine Performance

By Jim Montague

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It's always good to increase the scope of your awareness. Whether you happen to be a person or a machine, widening that radius means networking and communicating outside your usual sphere. Lately, a lot of human and industrial networking is being done via the Internet and in the cloud, but there's a point at which it all still depends on wires, cables, managed Ethernet switches, servers and other devices, which software-based interfaces and tools then coordinate.

For instance, Serac in Carol Stream, Ill., used pneumatic nozzles on its filling and capping machines, but users eventually requested more flexibility in order to easily change recipes to different products and quickly switch to different containers.

As a result, Serac developed and just released its new range of FC net-weight, filling-capping machines, which use Profibus for tasks such as coordinating load cells for weighing and stepper motors to control nozzles, so they can accurately fill containers from 50 ml to 1 gallon with a variety of products with varying compositions and handling requirements (Figure).

"Our users need to run thousands of different recipes for everything from window-cleaning fluid to potentially foamy mouthwash to very viscous cough syrup, and each of these products has to be handled differently and requires different valves, timing and nozzle settings," says Jean Luc Hostachy, Serac's technical manager. "Now, instead of changing valves, which could take anywhere from minutes to hours, operators just open a program, hit the right button, and the steppers and servos adjust the nozzles for just the right flow for that recipe and its container."

The FC machines employ nine circuit boards that each drive two stepper motors or two load cells for a total of 18 heads, which are connected to a slip ring, and controlled by a PC running proprietary software that Serac wrote for a Windows XP operating system. It also uses remote I/O modules and servo motors for machine feeding and all of them and FC's heads, PC boards, slip ring and I/O points are on Profibus, which is far simpler than wiring each device separately.

"Having stepper motors on the network doesn't just make the nozzles smarter and easier to adjust, it also makes them easier to clean," Hostachy adds. "We can just flush and be done, which means a lot less cleaning between products. In fact, this easier switchover even means FC can go tankless because it doesn't need a hopper."

Although deploying and networking I/O modules and managed Ethernet switches delivers these and other advantages, it's still important to make sure these new devices don't overload the network, according to Charlie Norz, product manager for I/O systems at Wago. "Fieldbuses are typically very robust, but as more and more devices get plugged in, signals can degrade, and they might not work as well," he explains. "So a network that only used to talk to PLCs could now have tablet PCs and smartphones trying to communicate with it, and that can add a lot of traffic. This is why it's important to divide networks into virtual local area networks (VLANs) and separate them with firewalls."

Less Cable, More Planning
Because industrial networking's primary commandment in modern times has been to reduce point-to-point wiring, it's no surprise that machine builders, end users, integrators and control/automation engineers have been using twisted-pair Ethernet and fieldbuses and their supporting routers, managed switches and other devices to help limit, design out or combine old-style cabling.

For example, Martin Kolb Steinbearbeitungsmaschinen in Bellenberg, Germany, builds sawing, cutting and polishing machines for natural stone up to 200 mm thick, and recently sought more integrated controls to improve accuracy and cost-effectiveness.

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