CHECK AND DOUBLE-CHECK Master Technician Michael Dilley inspects the corrugations of a grinding roll. Source: MPE
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The increased foreign sales also impact the machine control choices. “We offer either push-button controls or PLC-based systems,” explains Thomas. “PLC control allows us to provide 25 different recipes that control all of the important grinding parameters. However, many of our customers use their grinders for only one or two different products so the recipe control system doesn’t add much value for them. We try to offer our customers the controls package that makes the most sense for how they will use the grinder. We use primarily Allen-Bradley PLCs. The majority of our projects are customer specs, and A-B is often the supplier of choice. With our increasing sales in Europe, we are developing a PLC control system using Siemens.”
Recent completion of a multi-year effort to develop a single PLC program for its Granulizers has Thomas fully caffeinated. “That will handle 90% of our PLC-controlled Granulizers,” he says. “We made extensive use of the visibility control in the PanelView Plus touchscreen to allow us to turn features on and off and options for each project without writing custom code.”
MPE’s safety systems are hardwired Cat. 3, explains Thomas. “We use Pilz safety monitoring modules and A-B 700S-CF safety relays,” he says. “We haven’t used any safety PLCs. Our typical Granulizer only has eight to 10 safety switches that are in close proximity, so there’s really no advantage to more sophisticated safety systems.”
Security issues aside, Thomas also would like to see more remote access to customers’ machines. “I’d love to find a way to get Internet access to our grinders around the world,” he says. “Being able to remotely view all the operating parameters would greatly aid in advising our customers on how to best operate their equipment. I think this is more of a security issue than a technology issue. While all of our customers would like us to be able to access their grinders, the question is: How do they do so without opening their IT systems to unwanted access?”