Tshwane Metro, previously the Pretoria, Centurion and Arcacia City Councils, is now in the final phase of upgrading its telemetry control network. The system it selected for the next 10 years is the system from Specialist System Engineering, a leading system engineering company specialising in telemetry and tele-control solutions.
Previous systems
The previous systems, some more than 13 years old, from the different city councils in the new Metro is now being replaced by the new telemetry equipment from Specialist System Engineering. The vast area and location of the water network together with the fact that the older systems could no longer be maintained, meant that Tshwane was compelled to upgrade to a newer generation of telemetry equipment. The upgrading had to take place in phases, with the oldest and most critical stations in the remotest areas being completed first.
Telemetry from SSE
The SSE telemetry system was chosen for its advanced functionality and the unique requirements that the Metro has. Digital repeating, enhanced data-logging functions as well as the ability of the SSE-RTU to be programmed like a PLC, are all functions that made the SSE telemetry suitable for the Metro.
High-speed data radios
Tshwane Metro has more than a 100 outstations - and is growing by the day. For this reason it was decided that high-speed data radios were needed. With the high number of stations - and the data traffic on the system - bottlenecks were becoming a problem. SSE was contracted to upgrade the RTUs and analog radios with new high-speed data radios. The major improvements in data transfer speed increased the data throughput of the communication network significantly. The volumes of data from 100 outstations could simply not be handled by the older analog telemetry system anymore.
Radio path analysis
Due to the vast area the telemetry system is covering, and the fact that data integrity and radio link reliability is of the utmost importance, Tshwane Metro decided to do a comprehensive, theoretical radio path analysis. Again, SSE was selected to undertake this service to the Metro.
"Due to the growing demand and requests from more and more customers, SSE decided to purchase all the necessary software tools from Canada to execute comprehensive and detailed radio path analysis for two way radio, telemetry and microwave links. This is a new added service, to all our other services, to make SSE a complete one-stop telemetry systems house. This service is not available only to existing SSE customers, but also to other system houses and customers that struggle with communication problems. We at SSE now have the capability to quickly establish whether communication can be established in point-to-point or point-to-multipoint links," says Gert Bezuidenhout, MD at SSE.
Realtime data and logged data
Tshwane Metro makes extensive use of the features of the SSE telemetry equipment. These include the change of I/O state reporting and the intelligent data logger functions on the SSE-RTU. (User-selected I/Os are logged in the outstations at user-selected intervals.) This data is downloaded from the outstation to the master station computer, where it is trended and archived.
Scada upgrade
The Factory Link scada system was recently upgraded from the older Version 6.6 to the newest enhanced Version 7. The operator interface was upgraded, with enhanced alarming and trending functionality. The scada is also configured to send SMS alarm messages to cellphone users, notifying them of critical alarms within seconds of any alarm event.
OPC server
Tshwane Metro also selected to make use of the new enhanced version of the SSE-OPC Server, which makes the SSE telemetry equipment truly open. The user-friendly SSE configuration toolbox, incorporated in the OPC Server, makes it easy to add, edit and configure outstations. The data scope monitors all traffic on the radio data network, making it a useful maintenance and faultfinding tool.
"The fact that the OPC Server has the capability to save data directly into a SQL server database, and that FactoryLink can trend from this database, makes the history trending so much more comprehensive and thorough," says Jaco Rabe from the Metro.
For more information contact Gert Bezuidenhout, Specialist System Engineering, 012 663 4331, gbez@sse.co.za, www.sse.co.za
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