The dairy farm needed a pump system to access ground water from wells and ensure a reliable and cost-effective water supply. The farm’s owner commissioned a suitable system from electrical installation planners, Pienaar Elektries, which specialises in agricultural operations. Following an in-depth planning and consultation process, Pienaar Elektries opted for several automation products from Delta.
The planned irrigation system comprised two reservoirs at different heights, to be filled with water by a total of six underground well pumps overnight, when the energy costs were low. A transport pump is used to transfer water from the lower reservoir to the higher one. The height difference allows the sprinkler system to be operated using gravity alone during the day, making it particularly efficient. The farm animals and the dairy can also take their water supply from this irrigation system. The key requirements of the project were cost efficiency and low energy consumption.
Five low-energy Delta CP2000 frequency drives drive the six underground well pumps and ensure that the water brought to the surface is transferred on to the higher tank. The CP models feature a PID controller with feedback that allows the water level in the tanks and boreholes to be monitored and corrected. This is done by alternating between the different pumps and continually monitoring the flow. If the borehole level falls below a minimum predetermined by the user, the PLC control switches to the next the borehole and prevents the pumps from being damaged.
The system has various Delta DVP series programmable logic controllers (PLCs). Three DVP04AD PLCs monitor the sensors in boreholes and keep the water level above the predetermined value. Five DVP16SP PLCs regulate the motors. One DVP12SE PLC monitors the water level in the top reservoir and the animal watering stations, while a further DVP controller manages the sprinkler installation. Two human-machine interfaces (HMI) from the DOP-100 series are used to display all the processes in the system and show system information and warning indicators on a 7 or 15-in touch screen. In-house software also allows the time configuration and energy costs to be monitored remotely. Users can also monitor the entire process via the DOP-100 VNC server.
The system is now working without any issues and supplies both livestock and crops with sufficient water, even during periods of low rainfall.
