SSE's Cape Town branch has made significant inroads into the telemetry market in the Western Cape since the branch was established in September 2001. The Nelson Mandela Metropolitan Municipality contract is the largest sewage telemetry contract to go out to tender for many years in the Eastern Cape, if not the biggest of its kind to be installed under one contract.
Clive Maasch managing member, Cape Town Branch says: "We are extremely proud to be appointed for such a high profile and prestigious contract, the type of contract that certainly raises our profile as well as positions SSE as one of the major players in the South African telemetry market. The Eastern Cape area has become high profile in the engineering media of late with the large-scale development of the Koega Project and The Nelson Mandela Metropole have identified that the basic services such as the water, sewage and electrical will have to be managed efficiently with the future demands in mind."
Consulting engineers, Wolhuter & Associates and the client put together a specification to cater for the present and future needs of the management of the sewage network for the Metropole.
System description
The system comprises of three Adroit scada master stations presenting both operational and statistical information. Operational functions such as pump trip, alarms, sump levels and intrusion alarms vastly improve day-to-day management of the network. Valuable statistical data provide senior management with the tools used for planning of the networks demands brought about by the predicted domestic and industrial growth in the future.
SSE RTU-10 telemetry
Each sewage pumpstation is monitored by the SSE RTU-10 telemetry system, a total of 68 pumpstations at present. The SSE RTU-10 is fully programmable and is used to provide local control of the pumps as well as log data such as flows, pipe pressure and sump levels. The RTU has multiple serial ports for connectivity to other intelligent devices as well as expandable memory up to 10 MB for logging purposes. The unit's OPC compliance allows connectivity to all OPC compliant scada such as Adroit, Citect and many others.
SSE's RTU configuration toolbox provides a powerful user interface for configuring and programming of the RTUs. All configuration and programming can be downloaded to the RTU from the master station scada via radio or from a laptop connected to any of the outstations. In other words, any SSE RTU 10 outstation covered by the radio network can be used to interrogate any other SSE RTU 10 outstation in the network and be programmed or updated via the radio network.
Manufactured to IS0 9000 Standards, SSE's RTU can be used in many different applications within a choice of wide area networks ranging from digital or anolog radio, GSM, GPRS, fibre optic, landline and many more.
Instrumentation
Each of the sewage outstations employs an ultrasonic level transducer supplied by Flotron for monitoring the sump level continuously. Based on the sump level the Flotron ultrasonic schedules the pumps by means of four on-board relays.
E&H Cerebar pressure transducers monitor the pressure in the pump manifolds, which along with the levels and pump status are all monitored by the SSE RTU 10 telemetry system.
Digital data radio network
The system employs the MDS digital data radios imported by SSE as a wide area network suitable for communicating the data from each of the 68 sewage outstations back to the scada master stations. These radios have a fast 'key-up time (7 ms) and higher data rate (4800 baud) compared to anolog radios typically 150 ms key up time, at 1200 baud. This powerful radio network will be able to refresh the master station scada by polling each of the 68 SSE RTU 10 outstations (2000 I/O points) in about 80 to 120 seconds. This network has the capacity to expand with the future requirements of the Metropole.
For more information contact Clive Maasch, SSE Data Networks, 021 552 0420, [email protected], www.ssedata.co.za
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