Energy efficiency: Open, modular control system cuts waste, adds throughput
In the food and beverage industries, it’s not uncommon to find control systems that are proprietary and difficult for the end-user customer to maintain. A major U.S. meat processor needed to replace a control system for eight parallel material handling and storage processes at one of its plants and wanted build a nonproprietary, open system that could easily be maintained. The result reduced scrap by 10%, increased throughput by 15%, and cut troubleshooting time by 20%. Less scrap saves energy. Return on investment (ROI) for the automation upgrade is expected to be one year.
The plant’s PC-based system controlled a rotating carousel that transported 20- to 80-pound packages of meat through various stages of production, processing, and customer order fulfillment. Each package is unique, and a manufacturing execution system (MES) tracks the type of steer, the farm it came from, the cut and grade of the meat, as well as the specific location of each package. In addition, the control system must be in continual communication with the IT department for order fulfillment.
As part of an ongoing planning and systems review, the plant engineer identified the 15-year-old PC-based control system as outdated and difficult to maintain. The company could no longer change the control code nor enhance or improve the system. There also was no documentation.
High on the anxiety list was that the system would fail and not be repairable, causing an extended outage and lost productivity. The plant manager asked a major automation vendor, not the original supplier, to evaluate the system.
Commercial off-the-shelf, modular system
Since no control documentation existed for the original system, the automation vendor worked with the meat processing company to understand what the system was doing and the goals. The new control system communicated from the IT department to the mechanical devices.
The open and modular control system was built from commercial off-the-shelf (COTS) components, with a programmable logic controller (PLC) in seven control cabinets. Each PLC controls up to five servo amplifiers and motors for the upper and lower carousels as well as the robot axes, and a human machine interface (HMI) mounted in the cabinet door. The HMI provides real-time information and allows operators to manipulate and run the application.
The modular system design allows painless technology upgrades. More traditional systems would have to be almost completely redone.
Collaboration allowed easier adaptation as the new system developed; a “turnkey” arrangement would have been difficult since so little documentation existed.
Application software development, and code writing, was shared among the vendor and various engineering groups within the meat processor. The teams also worked with departments within the plant to ensure that the system met everyone’s needs. The team effort was especially important because the plant wanted to manage the system in-house after it was complete rather than outsourcing maintenance.
Other groups within the automation vendor offered design assistance, recommendations on product optimization, and verification of product capabilities. A French and German design engineering group within the automation company tested the system using simulation to avoid risking damage to millions of dollars of mechanical equipment. The meat processor didn’t have a place to physically test the solution without hooking it up to the equipment.
The single-source model provided streamlined interaction and one-on-one service.
Benefits, better performance
The meat processor gained a modern, nonproprietary, open, and modular control system, a 10% reduction in scrap, and a 15% increase in throughput. The old control system wasn’t always positioning boxes correctly or stopping on time, and this damaged boxes, which created scrap. With better controls, the system isn’t damaging product and can run faster. In addition, with the enhanced diagnostics and operator interface, troubleshooting time is reduced by 20%.
The company expects the new system will pay for itself in 12 months.
Technology notes: Automation choices
Schneider Electric, a supplier of power, control, and automation solutions, was asked to evaluate the PC-based control system even though it wasn’t the original supplier or system integrator for the meat processor.
A Schneider Electric Unity Premium PLC in each of seven control cabinets controls up to five Schneider Electric Lexium 15 servo amplifiers and motors for the upper and lower carousels and robot axes, and a Schneider Electric Magelis human machine interface (HMI) mounted in the cabinet door.
Schneider Electric worked with the customer on the system rather than providing something “turnkey,” which would have been difficult without documentation. Teams collaborated to write code and work with all plant departments to ensure that the system met everyone’s needs.
Schneider Electric collaborated with the meat processor to develop the new control scheme, drawing on its own global resources, using various groups within the company for design assistance, recommendations on product optimization, and verification of product capabilities.
Schneider Electric used its French and German design engineering group to test the system. Since the meat processor didn’t have a place to physically test the solution without hooking it up to the equipment, Schneider Electric used its European design engineering group to simulate various processes rather than risk damage to millions of dollars of mechanical equipment.
– Gary Sherman is an automation solutions senior executive account manager for Schneider Electric. He attended Purdue University, graduated with a bachelor’s degree in electrical engineering, and been with Schneider Electric for 33 years. He is based in Missouri. Edited by Mark T. Hoske, CFE Media, Control Engineering, www.controleng.com.
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