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 continually rising and expanding global markets have led soft drink manufacturers to invest in state-of-the- art facilities to ensure production continues reliably to meet demand.
One such company is Schweppes Australia. With a history dating back to 1783, Schweppes now offers more than 40 products. Schweppes Australia’s Huntingwood, New South Wales facility is one of its principle production plants, and has seen substantial manufacturing capacity increases in the last eight years.
As part of the company’s quest to improve operability, Schweppes Australia embarked on an upgrade to the syrup room control systems at its Huntingwood facility. The upgrade includes integrating 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 then 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 desti nation 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.
“All the sugar-based products leave scope for bacteria build-up and contamination,” he said. “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 crit ical to ensure no batch contamination.”
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 oper ating 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.
“We had the choice to either upgrade the system to a current version of the DCS, or to integrate the DCS function ality into the Rockwell Automation system,” said Ung. “Migrating the process control functionality to the 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. Sales director Ken Maxwell says that a key challenge 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 said. “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 job was to repli cate the functions of the legacy DCS using the ControlLogix platform, and 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,” said Maxwell. “The result is a system that is now more capable, more intuitive to the operator, and far easier for fault-finding.”
Unified plant 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, 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 I/O racks replacing 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 Integrated Architecture, PlantPAx provides a scalable portfolio of process technologies, solutions and services for plant-wide control. With built-in DCS and PLC functions, PlantPAx can be used for applications involving 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.
“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 said. “This capability allows the system to generate detailed batch and QA reports.”
According to Schweppes Australia’s Ung, the project 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 said. “The new system worked well upon first initialisation, with no issues to cause production delays in any of the lines.”
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,” said Ung.
“The upgraded system, by compar ison, is far easier for on-site personnel to fault-find.”
[Glen Jacob is the Rockwell Automation SI and OEM programme manager, South Pacific.]
