These meters provide information regarding the immediate measurements of their respective parameters. For instance, when clouds approach blocking the incoming sunlight, the current meter for Array 1 immediately shows a decrease in amperage, and resumes to its previous level when sufficient sunlight is available. The inverter load current readings vary as different appliances are powered-on for the AC loads. The digital meters allow users to see the immediate results of turning appliances on and off, and the immediate results of cloud coverage and clear skies. One limitation of these meters is no data storage is possible to provide a history of data measurements.
Data storage is provided by the computer data acquisition system.
In order for long-term data to be recorded, a data acquisition system was designed with the computer program Labview. The data acquisition system has provided the greatest challenge for the PV lab to date and is still in the refinement stage. Table 3 lists the variables which are being monitored by the data acquisition system. For instance, if within a 6 second interval, some external factor causes current from the arrays to drastically drop, the system will respond and take a reading of the fluctuation. As mentioned earlier, TSU's School of Technology was provided a 350 Watt wind turbine which was installed in October 1997 with the assistance from South African wind energy experts.