12 BACKGROUND INFORMATION

working of the webinterface

The webinterface shows real-time inverterdata and system status. So this has to be updated continuously. This is done via requests to the server. The situations that these requests should be made are when:

• the webpage is opened or gets focus
• there is new data available
• the system status has changed

The webserver doesn't know what happens in the webpage but does know when there is new data. This is true when certain events took place like:

• the inverters were polled
• the status of the zigbee system has changed
• the data was reset
• the time was retrieved
• night- or daymodus changed

So when there is new data, or the status has changed, the webpage has to be informed so that it can make the relative request. When there is new inverterdata it requests the data and when the status has changed it requests the status info. When the page was refreshed or got focus, both requests are made.
This way the proces is very efficient.