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Schweppes control in the can

When Schweppes Australia wanted to consolidate the process and logic control system in its Huntingwood production facility syrup room, a sophisticated automation and control system was chosen, based on the ‘PlantPAx’ process control solution from Rockwell Automation.

The demand for carbonated drinks is as effervescent as the beverages themselves. Their widespread appeal to people of all ages and cultures means that it is now possible to purchase these canned and bottled thirst-quenchers in some of the least accessible communities on earth. These expanding global markets have led soft drink manufacturers to invest in state-of-the-art facilities to ensure production continues reliably to meet rising demand.

One such company is Schweppes Australia. With a history dating back to 1783 — when Jacob Schweppe first perfected the practicalities of bottling carbonated water in Geneva — the Schweppes brand now encompasses more than 40 high-quality products. Schweppes Australia’s facility at Huntingwood, New South Wales, is one of the company’s principle production plants in Australia, and has seen substantial increases in manufacturing capacity in the last eight years.

As part of the company’s quest to improve reliability and operability, Schweppes Australia has embarked on an upgrade to the syrup room control systems at its Huntingwood facility. The upgrade included the integration of the process control functionality, previously the remit of a legacy distributed control system (DCS), into a cutting-edge control system based on the ‘PlantPAx’ process control solution from Rockwell Automation.

It’s all in the mix

Carbonated drink production relies on the preparation of flavoured syrups. Syrup manufacture is a batch process, using the basic components of raw sugar and treated water. At the Huntingwood plant, a continuous sugar dissolver is used to mix sugar into water to create a ‘simple syrup’. This simple syrup is prepared to a concentration of 62 degrees Brix — 62 per cent sucrose and 38 per cent water by mass — before being transferred to one of two 40,000-litre holding tanks.

A flavoured syrup batch is prepared by manually mixing flavour ingredients in a small ‘ingredients tank’, and routing this mixture to a final destination tank in conjunction with pre-prepared simple syrup and additional water. The control system is key to the management of the predominately automated process. An operator uses the control system to call up a batch menu, and to enter details of the required batch volume and the destination tank to be allocated. The system automatically ensures the volumes and proportions are correct, and the necessary ‘cleaning-in-place’ (CIP) has been completed before routing the mixture to the final destination tank.

According to Schweppes Australia project engineer, Warren Ung, CIP is a crucial part of the automated process for both the tanks and transfer lines.

“All the sugar-based products leave scope for bacteria build-up and contamination,” he says. “Cleaning comprises either simple flushing, a three-step CIP or a five-step CIP. The system initiates the appropriate CIP to prevent spoilage from the previous flavour that has passed through the tank. This is critical to ensure no batch contamination occurs.”

Logical choice

Prior to the upgrade, the control system in the syrup room was split between a legacy DCS for process control and batching, and an Allen-Bradley ControlLogix system — in conjunction with RSView 32 SCADA software — from Rockwell Automation. This latter system was installed to provide process control for additional lines transferred from the Alexandria plant in 2001. While these separate systems were operating satisfactorily in parallel, Schweppes Australia had growing concerns over the reliability of the obsolete DCS, the difficulty in sourcing spare parts, and the potential for component failure resulting in significant production downtime.

“We had the choice to either upgrade the system to a current version of the DCS, or to integrate the DCS functionality into the Rockwell Automation system,” says Ung. “Migrating the process control functionality to the Rockwell Automation ControlLogix platform was the natural choice, as this can achieve the same level of functionality as a DCS, but allows for greater flexibility for future expansion.”

Dickinson Autocon acted as system integrator to manage the upgrade. Ken Maxwell, Dickinson Autocon’s sales director, explains that a key challenge of the project was to extract the source code out of the DCS, in order to translate the functionality into ControlLogix.

“To integrate the DCS process control into ControlLogix, we had to painstakingly analyse every aspect of the DCS, to be in a position to replicate it in the new system,” he says. “It is a testament to the stability of the Rockwell Automation ControlLogix platform that it was possible to integrate the capabilities of the legacy DCS into it, with such a seamless result.”

Dickinson Autocon’s remit was not only to replicate the functions of the legacy DCS using the ControlLogix platform, but also to improve the operator interface and the reporting components of the system.

“The operator interface was improved through a replacement of all the screens and HMIs, and through upgrading from Rockwell Automation’s RSView 32 to the newest software version — FactoryTalkView Supervisory Edition,” says Maxwell. “The result is a system that is now more capable, more intuitive to the operator, and which is far easier for fault-finding.”

Unified plant process control

The primary user interface for the system is a SCADA and SQL server supported by three onsite clients — each running FactoryTalkView SE software. Operators use the SCADA to specify batch recipes, batch sizes, destination tanks and CIP requirements. The SCADA and clients are linked via EtherNet/IP to the ControlLogix controller, and small HMIs are connected via serial interface. ControlNet communications are used to network various process sensors and drives back to ControlLogix, which had its CPU upgraded to handle the two additional racks of I/O that replace the DCS.

The resultant Rockwell Automation system epitomises the company’s new PlantPAx solution for unified plant process control. Featuring a process control core based on the company’s widely adopted Integrated Architecture, PlantPAx provides a scalable portfolio of enhanced process technologies, solutions and services for plant-wide control. With built-in DCS and PLC functionality, PlantPAx can be used for applications involving both process automation and discrete functions.

Maxwell describes how all the process lines now link back to the SQL server database, facilitating more comprehensive and consistent capture of data, and consequently better reporting capabilities.

“Having all systems feeding data into the SQL database has meant a quantum leap forward in the system’s ability to extract data and populate a database,” he says. “This capability allows the system to generate detailed batch and QA reports, which can more easily be archived.”

According to Schweppes Australia’s Ung, the project implementation was designed to have a fallback position, such that the legacy system remained functional during the changeover period — although this facility was never actually required.

“This project has been a credit to Dickinson Autocon’s professionalism, and to the reliability of Rockwell Automation’s software and equipment,” he says. “The new system worked well upon first initialisation, with no issues to cause production delays in any of the lines. We had allocated time and resources to fixing issues, but, in the event, this wasn’t necessary. The changeover to the ControlLogix platform could not have gone more smoothly.”

Superlative support

Following on from the upgrade, Schweppes Australia now benefits from both a TechConnect support program with Rockwell Automation, and a service agreement with Dickinson Autocon.

“Previously, we had no site expertise regarding the DCS system, and there were only a couple of people in Australia with the technical expertise to program or fault-find the system,” says Ung. “The upgraded system, by comparison, is far easier for on-site personnel to fault-find — especially with the invaluable support that TechConnect provides. The service agreement with Dickinson Autocon further provides a surety that unplanned downtime can be minimised.”

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