Department of Water Affairs and Forestry (DWAF) selected Specialist System Engineering (SSE) to supply and install an advanced telemetry system for monitoring and control of the water network in and around Oudtshoorn.
Previous systems
The previous (ageing) system, parts of it more than 10 years old, has been replaced with new telemetry equipment from SSE. The vast nature of the area, the location of the water network, and the fact that the older systems could not be maintained anymore forced Overberg Water to request DWAF to upgrade to a newer generation of telemetry equipment. The upgrading has been done in phases - with the oldest and most critical stations in the remotest areas upgraded first.
Telemetry from SSE
"After an initial tendering stage, and careful evaluation of the various systems, DWAF selected the telemetry system from Specialist System Engineering due to its cost effective solution and enhanced features. Powerful features such as I/O mapping, PLC programmability, enhanced data logging functionality, OPC server connectability, etc, made the telemetry system from SSE an obvious choice," says Craig Hasenjager, electronic engineer and project manager from DWAF.
The new system
Water is a scarce commodity in the Klein Karoo, so a reliable telemetry control system is of the utmost importance, especially with stations located great distances apart. The new system consists of two systems, operating independently. The one system, called Dysselsdorp, consists of nine borehole stations, seven reservoir stations, five booster pump stations, reporting all remote field data to two scada software packages through a repeater network with three repeaters operating inline. The second system, called Calitsdorp, consists of five borehole stations, one reservoir site reporting all remote field data to two scada software packages through one repeater.
RTU-PLC programmability
The old PLC controllers at all the booster pump stations in the system were replaced by the SSE-RTU. These RTUs (with their PLC programmability) were programmed to do all the interlocking, the level control, the valve control and pump scheduling. "The fact that the SSE-RTU can also be programmed like a PLC, made the use of a PLC in the pump stations obsolete," says Hasenjager.
Realtime data and logged data
DWAF makes extensive use of some of the unique features of the SSE telemetry equipment. Over and above the change of state reporting of I/Os, is DWAF also using the unique intelligent Data Logger functions on the SSE-RTU. The user selected I/Os get logged in the outstations at user selected intervals. This data then gets downloaded from the outstation to the master station computer where it gets trended and archived.
Scada upgrade
The scada system has been upgraded to the newest release of the enhanced scada system from Adroit. Part of the SSE scope of work was to program and configure the Adroit scada for all the necessary, MMI, trending and alarming functionality as specified by the client.
OPC server
DWAF 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 very easy to add, edit and configure outstations. The data scope functions to monitor all the data traffic on the radio network makes it a useful maintenance and fault finding tool. "The fact that the OPC Server has the capability to save data directly into a SQL server database, and that Adroit can trend from this database, makes the history trending so much more comprehensive and thorough," says Hasenjager.
For more information contact Gert Bezuidenhout, Specialist System Engineering, 012 663 4331, gbez@sse.co.za, www.sse.co.za
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