The operational subset of the tracking system, named Electro-Mechanical System, is presented in figs 2 and 3.

This structure has two DOF, motorized by stepper motors with incorporated encoders, in order to track exactly the prescribed path.

The mechanical system was designed using standard industrial Aluminium profiles in order to obtain a simple and economic structure.

The mechanical structure is mainly composed by Bosch-Profiles and Aluminium plates.

The two motorized axis are composed by Step-motors assembled to Aluminium shafts.

Figure 2 illustrates the several main components of the mechatronic system:

Part n. 6 = Step-Motor to control axis 1;

Part n. 7 = Step-Motor to control axis 2;

Part n. 8 = Photovoltaic cell (150mmx150mm).

The PLC-tracker has the complete operational management of the tracking system. The main tasks performed by the system are:

— Control of the two step motors;

— Processing the data from both encoders;

— Processing the voltage signal coming from the PV-Cell;

— Processing the data from the external proximity sensors that informs the system about the hard-home position reference.

This PLC controls directly the tracking system and commands all other PV-Panels, from the solar Park, according to the developed algorithm. Figure 5 shows an example of a solar park with several PV-Panels.