With the ever-increasing requirements for remote water management and control systems, Vangard Digital has developed a PLC-based telemetry system. This system has all the functionality of custom-built telemetry systems with the flexibility of combining standard off-the-shelf PLCs as the remote terminal units (RTUs).
Over the last 30 years, South Africa has had the choice of a handful of local and international companies who have custom designed and supplied our local needs with homebuilt, and often expensive, telemetry systems. The client is then supplied with a product that is supported by only one authorised dealer, many of whom are fly-by-night companies, and so clients find that they continually have to fight for service and backup. Once the client has been hooked with cheap promises, prices are often escalated beyond reason... And so the local telemetry industry has stigma attached to it much like the second hand car business.
Due to the demand by the larger South African companies, Vangard Digital has developed a telemetry system that offers the client a system based on commercially available controllers that are competitively priced for the local industry. The objective of this product is to provide the clients with commercial equipment and a service-orientated supplier that will ensure they remain competitive.
Features
* Uses commercially available PLCs.
* All standard telemetry functionality is still available.
* Local control and safety interlocks can be done locally at each RTU.
* All development tools are commercially available.
* Full integration with scada software is possible.
* Radio communications is by means of high speed data radios.
De Beers - Venetia Mine
Vangard Digital has developed and installed a water management system comprising of 19 Remote Terminal Units, a master station and two remote scada PCs at De Beers' - Venetia Mine. The system allows for the full automatic control of the supply of water to the mine.
De Beer's main requirement for the system is to have a reliable open platform system using commercially available hardware and software in order that they have the freedom of choice in appointing their service contractors. The system was designed using the Siemens S7-200 and S7-300 range of PLCs. Communication between the Master Station, scada and RTUs is by means of high-speed data radios and industry standard communication protocols.
The system is a fully automatic unmanned telemetry system, controlling the water supply from 27 boreholes in the Limpopo Valley to Venetia Mine - 45 km away. All boreholes, storage reservoirs, transfer pumps and valves are remotely controlled to provide the mine with their water requirements of approximately 15 000 cubic metres per day.
With the delicate eco-system and harsh dry climate in the area, De Beers has placed a lot of emphasis on nature conservation and has ISO 14001 recognition for this. In order to conserve water, a storage dam was built to prevent year round borehole pumping. The telemetry control allows for two modes of operation. During the rainy season, when there is an abundance of water, WET MODE operation is selected and the system will pump into the storage dam. In the winter months, DRY MODE selected and each borehole is carefully monitored as to its own and surrounding water levels. Should the water table be insufficient to supply the needs of the mine, the system will automatically draw from the storage dam and allow the water table to rise.
This information is transferred back to two Wonderware InTouch scada computers where the system can be monitored and important statistical data is analysed to provide information on water consumption, wastage and any effects on the environment.
Vangard Digital believes that there is great potential for South Africa but we have to preserve our natural resources and provide world-class service and technology to reach this goal.
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