PLC addresses malting process reliability issues

An upgrade project featuring Mitsubishi Electric's latest PLCs has been completed in record-time, allowing Crisp to make a range of process improvements.

When Crisp decided it was being held back by a legacy control system, it decided to upgrade its control system and turned to Mitsubishi Electric for a solution. The upgrade – which was implemented in jut four days – has slashed downtime and empowered operators to fully govern the manufacturing processes, leading to improved product quality and consistency.

Keeping the delicate malting process balanced requires a responsive control system and timely upgrades to the plant are regarded as essential. Increasing the speed at which process anomalies are detected and responded to has a significant impact on the overall process. With batch sizes measured in tons, this was the main reason why Crisp decided to replace six legacy GEM80 PLCs with new high-performance Mitsubishi Electric Q Series systems.

David Spiers, group engineering manager at Crisp explained further: "The existing PLCs were becoming unreliable which left us exposed to the risk of unplanned downtime events. 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, it was becoming difficult to find spare parts. This issue was becoming increasingly impactful as the original PLC components were reaching the end of their service life and needed to be replaced. Engineers at the malting production site struggled to interrogate the old control system in order to troubleshoot, repair or modify the existing functions and it was not possible to adjust the processes involved to the extent they wanted.

To address these issues, Crisp contacted Suffolk Automation, a local specialist in process control systems. To source the new PLCs, Suffolk Automation's software engineers turned to Mitsubishi Electric.

Mark Chisnall, managing director at Suffolk Automation, takes up the story: "We're familiar with Mitsubishi Electric's full range of automation components. Technically the PLCs are well supported and for the customer the cost versus performance is good."

Six Q-series PLCs replaced the original PLCs around the factory. Technically this encompassed two plants at Ryburgh malthouse. All the PLCs were then connected via CC-Link IE, open Ethernet network with 1 Gigabit bandwidth, using fibreoptic cables. In this way, Crisp could benefit from real-time communications between the different manufacturing areas and upwards to enterprise level software systems.

"If we experience a power cut now it takes minutes to restart the system, not hours,” said Spiers. “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 solution also provided Crisp with the level of detail needed to have a greater understanding of real-time variations in the process. The operations team can now monitor and access parameters such as temperature and throughput live, anomalies are quickly detected and acted upon thanks to visible alarms. The wider management team benefits in-turn from better plant performance and more accurate reporting.