November/December 2019

42 n PLCs, HMIs AND SOFTWARE November/December 2019 www.drivesncontrols.com PLC upgrade brews benefits for Norfolk maltster When ageing GEM80 PLCs started to cause problems for a Norfolk maltster, it turned to modern controllers linked by 1Gbit/s fibre optic communications. The upgrade, implemented in only four days, has slashed downtime and given operators better control of the malting process, leading to improved quality and consistency. S ince 1870, the Norfolk-based maltster Crisp has been processing barley, cereals and other grains, supplying quality malts to food and beverage producers around the world. The company owns five production sites in the UK, and has additional malting capacity in Germany and Poland. To ensure optimal productivity and product quality, the company uses automatic control systems to monitor the processes it uses to convert grain into malt. Malting is a delicate process, because the quality of the raw materials can vary and the grain kernels must be kept alive if they are to germinate. Small improvements in process control can reap big rewards in terms of quality. With batch sizes measured in tonnes, keeping the malting process balanced requires a responsive control system. Increasing the speed at which process anomalies are detected and responded to can have a significant impact on the process. At one of its sites, at Great Ryburgh in Norfolk, Crisp was experiencing problems with ageing GEM80 controllers. “The PLCs were becoming unreliable which left us exposed to the risk of long-lasting, unplanned downtime events,” recalls group engineering manager, David Spiers. “For example, if we had a power outage, it would take the engineers 3-4 hours to return the system to full operation which, with our production process and fixed delivery schedules to meet, really wasn’t acceptable.” In addition, Crisp was finding it difficult to find spare parts for the controllers. This issue was becoming increasingly serious as the PLC components were reaching the end of their service lives and needed to be replaced. Also, engineers at the site struggled to interrogate the old control system for troubleshooting, repairs, or when they needed to modify existing functions. And the maltsters who operate the plant were unable to adjust the processes to the extent that they wanted. To address these issues, Crisp called in a local process control specialist, Suffolk Automation, to source PLCs to replace the GEM80s. It suggested using Mitsubishi Electric Q-series PLCs. “Due to the limited room available in the existing panels, conducting a phased system migration was not a feasible option,” reports Mitsubishi’s key account manager, Paul Judge. The entire re-fit operation had to completed in one go. Crisp, Suffolk Automation and Mitsubishi worked together to minimise downtime, and used a scheduled service window to replace the control system in just four days. Six new PLCs were installed at locations around two plants at the factory where the previous PLCs devices had been located. The new PLCs were then connected via the open CC-Link IE 1Gigabit/s Ethernet network, using fibre optic cables. This allowed Crisp to implement real-time communications between the different manufacturing areas and upwards to its enterprise-level software systems. Replacing the old control system has solved the reliability and support issues related to the GEM80 PLCs. “If we experience a power cut now,” Spiers reports, “it takes minutes to restart the system, not hours. The new PLCs save the live process data into permanent memory, so the system does not lose operating data or any updated parameter settings during a power loss.” The new automation system is also providing Crisp with the level of detail needed to give it a better understanding of real-time variations in its processes. The company’s operations team can now monitor and access parameters such as temperature and throughput live. Any anomalies are detected and acted upon quickly thanks to visible alarms. Crisp’s managers are also benefiting from better plant performance and more accurate reporting. The maltsters now have a control system that is user-friendly and easy to adjust. They can modify and fine-tune the functions and process parameters that govern various aspects of the malt. “We are extremely pleased with the results,” says Spiers. “As there are other areas in our plants that could also benefit from more up-to-date process automation, we will continue with the upgrade of our control systems and work towards achieving a smarter factory.” n Six PLCs were installed at locations around the Crisp factory and connected via fibre optics using 1Gbit/s Ethernet network. Image: Crisp