Solar WEB is an application whose purpose is collecting of data from a solar plant. By solar plant, we mean a solar installation (including devices to collect the solar energy and devices to control them, all wired into a network).
Here is a short list of the advantages that this kind of application has:
Remote monitoring and commodity in usage. In the most situations, the solar installation is not installed at client’s office, so that keeping in touch with the hardware system could be a tedious and time consuming activity.
Data storing. The hardware system has the possibility to show the current values and parameters (and that id done in an unfriendly manner). The software provides a way of storing the information into a database. In this way, the client is able to build graphics showing the variation of different parameters.
Reliability. Reliability of our system comes from two directions: on one hand, the systems and tools that are used (that is a java application on top of a linux OS) and, on the other hand, the quality of our code.
“Photovoltaik – that is river from renewable energies, generation of current without noise, without chemical processes and without production of dangerous carbon dioxide (CO2), that is responsible for the greenhouse effect on our planet. The energy potential of our sun is enormous and after human discretion inexhaustible. Over the year it radiates 15,000 times more energy on earth than we at present uses. Even in Germany the hitting solar radiation exceeds our power requirement around the 90fache.
In the context of the promising concepts for the use of regenerative energies public utilities on the area of the Egelsbacher of airport established a plant for the production of energy from sunlight. In addition 450PV mono-crystal modules are installed on the unused surface of the roof of one airplane-maintenance-resound. This, on the roof resounds to 5, installed solar electricity plant produces river for the supply of 8 to 10 single-family houses. The stringers so-called to 12, hooked up test specification modules of the type BP 585 give their direct current to 12 inverters type of the SMA Sunnyboy, which then into the public public utilities net feed will. As data logger a SMA Sunnyboy control is used +, which is attached via power LINE carrier, i.e. the data are transmitted over electricity mains. This has to supervise the task the individual inverters as well as the modules of the stringer and to make the data available for this web page.” (http://www.stadtwerke-langen.de/)
The solar network contains twelve WR systems (panels that collect through photochemical reactions the solar energy) connected at a Sunny Boy Controller Plus (SBC+). Our software connects to the SBC+ through the serial port (the communication protocol is a java-implementation of SMA’s network protocol – Sunny Net).Then all the collected data is send to one of our database servers (for minimization of the costs, the computer is connected through dial-up).
The program will periodically collect data from the SBC and store it into a database system and (temporary only) on the local file system. There are two main components that should be described: the SBC communication procedure and the database structure.
The communication procedure’s basis is the Sunny Net protocol specification (see SMA’s documentation SWRNET-11:KE3197 – named in this document as “communication protocol”). We will resume to a short description of the implementation.
A device represents a hardware component, commonly connected to a network, and using a well-defined protocol to communicate. The Java mapping of one device is represented in figure 1. The device is characterized, on one hand, by its serial number, provided by SMA and its name (in SBC’s case, this name is variable depending on its configuration). On the other hand (regarding the device as a network component), it is characterized by its network address. For more details, please consult the communication protocol (page 10).
The useful information is stored into a set of channels (organized into a java Hashtable object). In the following paragraphs we will analyze the structure of a channel.
The communication between devices and between PC and SBC is made using telegrams (mapped in Telegram class). Within this project, the following three communication parts will be met:
Sunny Boy Channels detection
Data Acquisition is the most important process in the whole application.
The future steps in developing and improving the system will include:
Email notification if any error occurs;
Cost reducing (that is at network load mostly);
Remotely updating of the code and control of the system.