This won Xstrata an award for its TIA solution, says Siemens product promoter Rocco de Villiers.
He says that the system used at Steelpoort is similar to one that Siemens installed at the Two Rivers platinum project.
“The control system solution consists of a supervisory control and data acquisition (Scada), or programmable logic controller- (PLC-) type architecture from the Simatic product range. As the products –such as industrial PCs, HMI, PLC, industrial networking equipment, drives, switchgear for example – were all sourced from one vendor and integration, based on good engineering practices, was imple- mented, a tangible saving was achieved on engineering work hours,” explains De Villiers.
One of Siemens’ top system integrators, IControl, together with an engineering team from Xstrata, was responsible for the integration of the project.
The control system architecture can comprise three physical layers – Ethernet, profibus and actuator sensor interface.
In Xstrata’s case, the Ethernet level, consisting of Simatic Scalance- managed switches from the X400 modular range, and the Profibus level, consisting of an optical link module fibre backbone, was used.
“Fibre-optic cable was used, where it was economically viable, to protect the electronic components against lightning strikes, as well as to facilitate the physical layout of the plant areas. “Over 10 000 m of optical fibre has been installed.” According to Siemens, the Simatic WinCC engineering and devel- opment software and visualisa- tion platform is designed on an open technology philosophy and nonproprietary structure, allowing easy interaction between different platforms.
The licensing structure is modu- lar and can be designed in a way that accommodates expansion through power packs and add-on packages.
“In general, automation and IT solutions are not designed without the possibility of the inevi- table change. “Solutions are subject to continu-ous changes that are implemented on a step-by-step basis throughout the process life cycle,” comments De Villiers.
He says that these solutions can include future modernisation of individual plant areas and plant expansions, implementing centralised monitoring of the total plant or of different sites in a conglomerate.
According to De Villiers, to facili- tate the continuously changing requirements, expansion of the process visualisation platform is a necessity in order to maintain the initial engineering investment and seamlessly integrate the change of scope.
“Simatic WinCC offers the required scalability, from a single-user solution that can be migrated to multiple server or client architectures.” The WinCC Scada platform facilitates integration of process- related data into the management of information systems, manufacturing execution systems and enterprise resource planning environments through its use of open industry standards. This data is aggregated seamlessly into the high-level environments to facilitate plant optimisation by monitoring key performance indicators.
“The Simatic WinCC/Redund- ancy option allows multiple ser- ver PCs in a parallel configuration ‘bumpless’ changeover, as well as seamless transparency of data.
“The system does not only switch to its redundant partner in the case of a failed server, it also does this in the case of disturbed process communications or applications,” states De Villiers.
When the failed server resumes operation, the contents of all message and process value archives are automatically transferred back to the restored server.
With higher levels of system availability, it facilitates high system availability and continuous process production.
The control rooms are equipped with two operator station personal computers with dual screens, running on the Scada network, enabling the operators to visualise the whole process plant area.
Siemens also installed a plant information system, called Simatic Dat@Monitor, that allows displaying and evaluating of current process status conditions and historical data on any office PCs, using Internet-capable tools, such as Microsoft’s Internet Explorer or Microsoft Excel.
Siemens says that precommissioning training was given on the project to the production and management personnel, enabling speedy operation and use of the systems.
Further, data from the remote motor control centres were networked through a process field bus (Profibus) fibre-optic backbone cable to the PLC stations housed in a central environment-controlled area, containing uninterruptible power sources and air conditioners.
“This enables centralised engineering and faultfinding of the control system components throughout the remote plant areas. Problems of compatibility were eliminated because Siemens supplied most of the control system components specified.
“Vendor product communicating with vendor products across the different network levels was easy to integrate owing to the single-vendor approach,” explains De Villiers.
Apart from this approach, it was decided that all instruments should have profibus interfaces where possible, ensuring ease of use for the end-user.
The installed base of instruments included 56 flow meters, six belt scales and 24 density gauges.