HI there i'm back to this project...

I'm measuring the acs714 right (i believe ) but i don't know how to do the watt/meter part...

i get watts doing Amps x Volts for instant read i gues is ok ...

now how do i know how many times should i read and sum ?

like

whatthour=wahtthour+readwatts /3600 seconds

if i do this i must read it once each second ? but i will loose measuring between... i bit lost...

Summary:

how do i get a watthour measure reading amps&volts from a dc source... ??

Read the current and voltage many times per mains cycle (lets say 1000 times a second), computing the instantaneous power from each set of samples. Sum these samples and scale the result according to the time between samples and you have a value that is the total energy over time. Sample and reset this value every second and you have measured the average power every second...

If you are only interested in watt-hours, then this is simply the energy (in Joules) divided by 3,600. For kilowatt-hours divide by 3,600,000