I operate an opensource system called EmonCMS to record energy usage for a client ([url removed, login to view])
EmonCMS uses the following work flow:
1. data from a remote energy meter posts data to EmonCMS using JSON in the URL String (this is called and input in EmonCMS)
2. EmonCMS then allow for the editing of the incoming values and is then exposed to a dashboard (this is called a feed in EmonCMS, each feed has its own table in mysql)
3. a feed is then used in displaying data on graphs and gauges.
I need to add the following functionality to the system:
Add a feed option to save a value, where the value is the difference between the beginning of the month and the end of the month. For the current month it is to be a growing value until the last day.
The purpose of this addition is the client has a energy meter that has a value KiloWatts / Hour (KWh) that infinitely grows from when the meter first turned on. I need to display on a dashboard the monthly KWh used on a bar graph.
because the value continually grows at the begining of the month this value maybe 4000 and at the end of the month the value will grow to 5000 I need to show the value 1000 on the graph for this month. The data for the current month is to continually update the most recent saved value until the month ends then create a new record in the feed table.
When data enters the site value is to be processed and saved as per the other processing methods in this application.
If more detail is required please as see screenshot for the area of the website where this option is to be added.