Process Dynamics has recently completed a new scada system for Parmalat’s yoghurt manufacturing plant in Kyalami, where the FactoryLink 7.5 scada system has been used successfully for almost six years. FactoryLink was acquired by Siemens when it bought the UGS Corporation in May 2007. Siemens’ main interests in UGS was its product lifecycle management software and the fact that FactoryLink overlapped with Siemens’ own Simatic WinCC scada range. In February 2009, Siemens announced that further development on FactoryLink would be discontinued and worldwide support would cease from October 2010.
Background to the project
Locally, there is very little or no support for FactoryLink, thus hindering future expansion projects and modifications that Parmalat had been considering. With the emphasis on scalability, openness and user friendly interfaces, Parmalat made the decision to replace FactoryLink with WinCC version 7, thus providing itself with all the benefits of the ‘Totally Integrated Automation’ concept from Siemens.
Two options are available for migrating FactoryLink to WinCC, the first being a FactoryLink Migration Package offered by Siemens and the second, re-engineering the project on WinCC from scratch. After considering these options, the latter approach was taken as the associated costs for each option were comparable. Parmalat’s requirements for the system did not just rest with a conversion to WinCC. It also had a need for a system integrator who could maintain, support and add additional functionality to WinCC and the Siemens S7 PLCs linked to the scada. The PLC software was originally written by an overseas SI six years ago and support has been difficult to come by. Process Dynamics, based on its strong business relationship with Parmalat and the strong local support it can provide was chosen to implement the new system.
The migration to WinCC
The system configuration consists of two servers communicating to a Siemens S7-400 PLC and three other S7-300 PLCs via standard Ethernet TCP/IP links. This S7-400 PLC is at the ‘heart’ of the manufacturing plant and processes and manages the entire production process from uploading raw milk, standardising, pasteurising, fermentation and transferring the yoghurt to the filling lines.
The first server is running WinCC Runtime & Configuration software. The second server is only running Runtime software. These servers have been configured with a redundancy link between the two; approximately 14 000 tags have been configured.
One of the requirements from Parmalat was that the new system had to resemble the FactoryLink graphic interface as closely as possible, so that minimal training and adjustments were required by the operating personnel. These requirements have been adhered to with enhancements to the process graphics.
A means to fine tune the production process has been achieved by using WinCC’s reporting and event logging features. Trend reports were developed to for critical parameters such as temperature, pressure, conductivity and flow during the production process. Upon starting of a process, a trend report is initiated, logging the start time, equipment and type of process. Upon completion, the end time is logged and a trend report is automatically printed out with all the aforesaid parameters. These reports have been particularly useful in highlighting areas that needed attention to ensure production stays optimised as far as possible.
Another tool that has helped in fine tuning the process is event logging. Each step of a process is logged detailing the start time, end time and duration of each step. If a step has taken too long for completion, an analysis can be done to determine the cause of the delay and the necessary corrective actions can be put into place.
Two servers are better than one
A problem regarding the FactoryLink HMI was that of reliability. The previous FactoryLink was not configured with any redundancy and in recent times, the FactoryLink HMI had become unstable and would ‘crash ‘now and again. This influenced production negatively for a short period of time, while the system was brought back online. With the inclusion of WinCC Redundancy, the availability and reliability of the scada and the system as a whole is enhanced by the parallel operation of the two interconnected servers and the automatic switching in the event of a malfunction.
The servers monitor each other in runtime to allow for an early detection of a failing partner server. In the event of a failure, the active server will continue to archive all messages and process data. When the failed server comes back online, the contents of all messages, process value and user archives will automatically be copied across. The gap in the archives caused by the failure is closed by transferring the missing data to the failed server. This action equalises and keeps both servers current.
Remote reporting functionality
The system is also equipped with WinCC DataMonitor. This software allows remote web access to the WinCC scada application via the intranet/Internet. This is particularly useful for the production and plant managers who may need to check on certain aspects of production in real-time without having to be on the factory floor.
DataMonitor provides a collection of analytical tools for the interactive data display and the analysis of current process statuses and historical data. For obvious reasons only selected functions are available via remote access.
Using the ‘Reports’ function, reports can be triggered with time control or event control. The reports can be created from WinCC print jobs or from published Excel Workbooks. This also allows for statistics and analyses of certain process data or historical data. The reports are created in PDF format and passed on as e-mail if necessary.
Some of the realised benefits of the new WinCC scada are:
* Better scheduling of processes and operations due to newly introduced process interlocks.
* Better quality control due to new CIP and process report functionality.
* Better availability and reliability of the scada system.
* Remote monitoring and access to data of the manufacturing process.
* Easier fault finding due to alarm and event filtering.
* Engineering has been simplified as OPC software configuration is no longer required.
* Ease of use – engineering and runtime.
Parmalat has plans to incorporate other parts of the plant like the fresh milk handling process into the WinCC system eventually. WinCC has provided a platform for Parmalat to implement future plans successfully and with relative ease when the need arises.
For more information contact Kobus van Niekerk, Process Dynamics, +27 (0)11 394 5412, [email protected], www.process-dynamics.co.za
| Tel: | +27 11 394 5412 |
| Email: | [email protected] |
| www: | www.process-dynamics.co.za |
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