Traditionally, system integrators have developed custom solutions that were specific to a particular configuration of hardware and software. This made them unmarketable to a broader audience while often limiting their scope for modification with the original client through non-conformance with standards. This all changed with the introduction of the ArchestrA Object Toolkit.
Case study: Geita gold mine
In 2006, decreasing production at the Geita gold mine in Tanzania prompted AngloGold Ashanti to investigate and to make some hard business decisions. The loss of skills at all levels throughout the process plant necessitated the implementation of automated control as far as possible to reduce variability and increase control expertise.
AngloGold Ashanti called in South African based system integrator, Systems Anywhere, who had previously successfully addressed such problems for the company. Over a twelve month period, Systems Anywhere installed a completely revamped control system based on Invensys Wonderware solutions that would:
* Apply the corporate standard.
* Standardise the control philosophy.
* Improve the alarming and alarm logging for analysis.
* Maintain a history of production data.
* Provide for real-time and scheduled reporting.
* Incorporate an Expert Operator based on fuzzy rules to reduce milling process variation and improve production.
Other client requirements included a maintenance plan and 24/7 support of the control system software in spite of the remoteness of the site.
The end result was a great success for both client and system integrator. “This solution allows us to fine-tune rules instantly,” says Phillip Stevens, senior instrumentation technician at the Geita mine. “Where previously the operator had to change mill parameters every six minutes, the metallurgist now changes the rules every few days. Average throughput is up by as much as 30%.”
About the Expert Operator
The Expert Operator is a rule-based (Fuzzy logic) system which allows an ‘expert’ to configure a controller to respond to predefined scenarios in a desired manner. The Expert Operator takes over the functionality of changing the set points from the human operator to bring the mill to peak performance in the shortest time.
To do this, three elements are involved:
* Filtering of the process variables individually through a moving average and checking them against their set parameters.
* Comparing the result of each variable against the rules that are stored in the database. The result is analysed to determine whether the set-point needs to be increased or decreased.
* This is then applied to a time interval (i.e. how quickly the system needs to react to the rule to ensure that production is kept consistent).
The Expert Operator is programmed to check the average of the variables and to adjust the set point every ‘x’ minutes in order to maintain peak performance in spite of an ever-changing environment.
“This is a very complex system,” says Barry Searle, software development manager at Systems Anywhere. “However, with the help of ArchestrA, the Expert Operator was able to be implemented faster than with traditional means which means a lower-cost solution for the client. Also, the operator is now free to multi-task rather than focus only on monitoring the mill performance. The operator is also free to fine-tune that performance without recourse to us or anyone else. What’s more, the operator no longer has to tweak the mill every few minutes because the metallurgist can control the Expert Operator to cope with new rock conditions or other issues through the selection of pre-configured profiles.”
Packaging the solution
Now that Geita mine had a proven Expert Operator productivity solution, the next step was to ‘wrap up’ all the rules and technology to make the Expert Operator into a single package.
To do this, Systems Anywhere used the DotNet3.5 engine, C#, SQL Server database and the ArchestrA Object Toolkit. “The toolkit allowed us to take technology that would have taken a system integrator weeks to implement on site, into a single convenient package that not only caters for previous work but that can be deployed in a matter of minutes,” says Searle. “This then becomes a licensed object that prevents it from being copied indiscriminately.”
Expert Operator packages are imported at the click of a button. The database comes pre-configured with proven defaults and complex functionality can now be implemented in minutes. Provision is also made for multiple profiles so that users can set up profiles for common scenarios. This means that a simple configuration change allows users to change the mill from an aggressive profile to a more conservative one.
System Anywhere’s Expert Suite of solutions can run through ArchestrA or standalone and has a SQL Server database. “It allows us to incorporate innovative solutions into ArchestrA without having to maintain a separate codebase,” says Searle. “By wrapping the object in an ArchestrA layer, the plug-in is scalable, versatile, fast to implement and brings our knowhow to customers in a convenient format.”
Benefits
* Throughput up by 30% (e.g. 300 ounces at nearly $2000/ounce = $600 000 daily or more than $13 million of additional monthly revenue).
* Operator freed for other tasks.
* A complex control solution is implemented in a fraction of the time it normally takes.
* Economy of scale brings the cost down.
* The Expert Operator gives Geita predictable, peak performance at all times.
* Change the profile, not the rules. One of the chief reasons for metallurgists having to change the rules is changing rock conditions. Adding the Expert Supervisor level of control allows the metallurgist to add multiple profiles. This means that, instead of changing the rules, the metallurgist just selects the profile that best matches current rock conditions.
* The upgrade requires installation of a new object, but this is instantaneous and does not require intervention by the system integrator.
What is next for Geita?
* Equipment utilisation – Systems Anywhere has developed an ArchestrA plug-in that writes aggregated equipment utilisation data to the system’s database. All that is required to use this is to drag it under the equipment to be monitored in ArchestrA and it starts logging.
* Expert maintenance – this includes run-time and service interval tracking with the automatic generation of work orders etc. for maintenance systems such as SAP.
* MMRS Integration – integration with the AngloGold Ashanti global business management system.
“We are now able to link into any of the company’s business management systems for reporting purposes,” says Searle.
Conclusion
Systems Anywhere is using the ArchestrA Object Toolkit to take system integration to the next level while Geita Gold Mine is pushing the envelope to extract the maximum from its plant as well as from its investment in Wonderware solutions.
“From a system integrator’s point of view, the ease of implementation of complex solutions cannot be overstated. If you can dream it, ArchestrA can do it,” says Searle. “But more than this, solutions often are not a perfect fit and, as in this case, we were able to fill the gap with the Object Toolkit which has allowed us to integrate 12 years of custom solutions and the expertise that went into their development into a de facto world standard – ArchestrA.”
For more information contact Jaco Markwat, Invensys Wonderware, +27 (0)11 607 8100, tech@invensys.co.za, www.wonderware.co.za
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