Chart with diff value?

[C.Ligthart]

In homeseer i have devices with the total ammount of energie used. These devices are counter values coming from rfxmeter devices.
Is it possible tot generate a chart with point that represent the change in value instead of the actual stored value?

[Michael McSharry]

You would do this type of thing by using virtual devices and have mcsTemperature chart the virtual device. For example, run an event at the same rate as you are having mcsTemperature put data into the database. You event action should be somethiing that likely can be done in a one-liner to subtract a value and store the resut in the DeviceValue of the next virtual device.

When mcsTemperature collects data from a device then certain reasonable values are generated automatically. It is typical to produce data that represents a total and a rate so in the case of wattage you see the accumlation througout the data and the rate it is being using at any given time.

[C.Ligthart]

Ok, so I need to run a script every 5 minutes (database storage interval) which sets the amount of power used during the 5 minutes, in a virtual device.
Thats no problem but to keep the script and the database storage in sync, is it possible to let mcstemp to run a script before it begins to store values?

[Michael McSharry]

If you think aliasing will be a problem, then have your script write to a .csv file rather than to virtual device and have mcsTemperature input the .csv file.