## 2 Overview of the Proposed System
Nowadays, despite the relevant refinement of production technologies during the last years, many plants still don't have any optimization of their energy production, resulting in an overall efficiency that is lower than the real capability of the plant. To achieve such an ambitious goal, a system infrastructure has been developed made up of the following modules (Figure 1):  
1. A _Monitoring Center_ (MC Structure in Figure 1) receiving real time data and images from sensors in the photovoltaic cells and from other sources (meteorological and solar radiation). This _Monitoring Center_ integrates a set of tools to monitor production as well as to detect failures and to send alerts through different communication channels (PC, phone, smartphone, _etc._). Additionally, it can estimate, through an innovative integration of data analysis (automatically stored by the system) and weather forecast, the potential production of energy power The  
Figure 1: General block-diagram of the system framework. Monitoring Center_ is also equipped with a surveillance system against thefts and actions of vandalism, and might also be able to control the orientation of the solar cells in order to maximize the energy production. 2. A wireless network integrating wireless sensors by means of a Zigbee-based protocol (_Monitoring Plant Network_, MPN structure in Figure 1). This network is in charge of collecting relevant data and sending them to the _Monitoring Center_. 3. A _Monitoring Environment_ composed by sensors measuring physical parameters of the plant and of the single solar cell, but also environmental parameters such as, for example, effective solar radiation. The _Monitoring Plant Network_ has a central role in the system: it monitors PV status and sends real-time information to the _Monitoring Center_ system. The _Monitoring Plant Network_ is based on the concept of \"smart\" PV modules, in which sensors and electronic components are set to control each panel or group of few panels; these _Smart Modules_ are able to sense voltage, current and temperature and to send information through a wireless network at a service center (_Monitoring Center_). The measured data will contribute to achieving both a local and a global vision of the behavior of the PV plant. These data can be integrated in the _Monitoring Center_ structure with other relevant data, such as historical, season and meteorological data in order to analyze the efficiency of the PV plant. At the same time, these data will also allow users to develop new capabilities related to dynamic power point tracking at the _Smart Module_ (or group of modules) level, automatic safety detection (fault prevention), night time theft monitoring and real time response. The overall architecture presents a modular and flexible structure based on open source technologies. As a result, it will be easily adapted to any context and environment. This paper will mainly focus on the description of the sensors attached to every solar cell (and their associated circuitry) and on the protocols established to make that information reach the _Monitoring Center_, where it will be appropriately dealt with.