Developing control systems for the successful operation of a major whisky bottling plant is a pleasurable but none the less demanding task. Here Richard Sturt explains how a major whisky distillery in Scotland reaped the rewards of investing in the very latest control technology.
Built to replace an older facility in the town, the extension to Allied Distillers' Kilmalid plant in Dumbarton is the first, fully integrated, single bottling and manufacturing facility in the scotch whisky industry.
Bottling other delights as well as whisky, it produces over 10 million cases of scotch, gin, vodka, liqueur and specialist products annually. To cope with this diversity required a major upgrade and expansion of the control system.
It was the perfect opportunity to incorporate Rockwell Automation's new ControlLogix architecture throughout the plant. ControlLogix replaced existing Allen-Bradley PLC-3 and PLC-5 controllers and new ControlLogix systems were installed in the bottling area.
The new facility makes extensive use of intelligent plant devices such as motor overload relays, networked on DeviceNet. There was also the requirement for a high-speed plant network to gather the increasing amount of data that Allied Distillers wants to analyse, in order to optimise plant performance.
ControlNet is used as the main plant network, collecting information from all areas and sending it to the supervisory system. The flexible networking architecture of ControlLogix was ideal for this complex task, allowing easy implementation of new networks as well as integrating with existing RIO and DH + networks.
The existing PLC-3 programs were converted to ControlLogix format by specialist company Javelin within a matter of days.
The Allied engineers then spent four weeks checking and configuring the communication structures to talk to their process control system. The system was installed over two weekends, with the first being used to check all communications and carry out any minor modifications. The following weekend the system went live with no impact on production.
Whisky a case for good control
Making whisky is a time consuming process. Grain whisky comes in by tanker and malt whisky in casks. Up to 50 or more whiskies can be used in one blend and an error such as using a 30 year old whisky instead of a five year old can be very expensive, so good control is essential.
The first ControlLogix takes care of the vat control room where the precious liquid from the tankers and casks is handled. The new system takes up a fraction of the space, is easier for operators to set up and offers more precise control. This is a hazardous area and uses ControlLogix 1756I/O to cut the pumps and avoid overspill.
Allen-Bradley E3 relays are used on the vatting and tanker stations to create intelligent motor control centres (MCCs). The E3 is an intelligent overload relay equipped with a range of sophisticated features that extend beyond enhanced motor protection. These include supplemental I/O, control capabilities, and the ability to operate in failure-prevention mode, allowing the engineers to monitor motor operation to prevent and minimise production downtime.
Unlike traditional overload relays, which are reactive (a fault condition trips the relay and stops production), the E3 and E3 Plus relays incorporate advanced warning functions that gives notice of conditions that could disrupt production and allows the engineers to take avoiding action.
Built-in DeviceNet ports allow access to status information and data. Diagnostic information available via DeviceNet includes device, trip and warning status, time to trip/time to reset (overload), and history of the past five trips. Using the intelligent E3, Allied Distillers can easily see if motor current changes or a pump runs dry and take action before there is a failure and lost production.
The E3 also has its own built-in I/O, which is used for overfill protection. The pumps and mixers use Allen-Bradley 1305 and 1336 variable speed drives for efficient and precise control. The E3 relays, PanelView screens and drives are all connected using DeviceNet.
After the liquid is entered into the system and blended, the next step in the process is filtration. This again is a hazardous area but has more analogue I/O as temperature and flow, for example, are vital to the filtration process. The product is then ready for bottling.
Here ControlLogix controls 16 lines of filling, capping and labelling machines providing the supervisory control for the main bottling halls. A somewhat complex operator panel has been replaced by an Allen-Bradley PanelView 1000 to provide operator control and information including start and stop to spacing, weight and a summary of cases to make, and cases made.
Ten million cases per year are palletised before going into one of two automated warehouses currently controlled by Allen-Bradley PLC5s.
Easier product improvement
The project has been a major success and Stephen Trainor, electrical engineer at Allied Distillers, is delighted with the outcome. With only one year to complete the whole project involving the new facilities and a new head office, everything had to go together smoothly.
"One of our major problems in the past has been lack of standardisation. In the filtration area we have improved repeatability by taking away some of the operator''s idiosyncrasies, allowing us to conduct product improvement experiments more easily,“ he said.
The project required significant expansion to the existing systems and these changes had to be made with the minimum of disruption. ControlLogix's flexibility and its ability to connect to the existing systems allowed essential areas of the plant to be upgraded while still maintaining operations.
The plan was to maintain the existing Data Highway and Data Highway Plus networks with the new ControlLogix PLCs and then switch over to ControlNet. If there were any problems with ControlNet, the system could revert to the existing networks. In the event the careful planning paid off and the plant wide ControlNet network was quickly established.
"With ControlNet, we can now link the whole plant and, looking further ahead, we will be enhancing the integration of the overall manufacturing and management system. Overall, increased access to real time data will be a great help in achieving optimal plant performance and profitability. I look forward to that day, but in the meantime am very happy with what Rockwell Automation's ControlLogix has allowed us to achieve,“ concluded Trainor. p
Richard Sturt is Business Unit Manager with Rockwell Automation Limited, Milton Keynes, England, email: rsturt@ra.rockwell.com, tel 00 44 (0)870 242 5004, fax 00 44 (0) 1908 839696, www.rockwellautomation.co.uk
