in the software emontx sample is the code for the power that uses a voltage measured:
if (CT1) {
emontx. power1 = ct1. calcIrms (1480) 240.0;
Serial .print (power1 emontx.);
does anyone have an idea to get the correct voltage of your system?
Hello
Re: use the right voltage
To measure voltage as well as current, you need to use some extra hardware and a different sketch. If using all the standard components, the measured RMS Voltage value should be fairly close to the actual one. Otherwise, you'll need to calibrate your result against some known standard.
Measuring voltage as well as current allows a much more accurate value of power to be calculated, especially at low levels of power. When measuring current only, any background noise in the system gets squared so you're never likely to record 0W when no power is flowing. If measuring both V and I, you can expect to see no more than a couple of Watts in idle conditions. The actual value will depend on exactly where your sensors' mid-points are sitting within the ADC's input range.
Re: use the right voltage
Measurement implications of ADC resolution at low current values will hopefully explain the mechanism by which the low readings acquire an error.
What Calypso_rae didn't say was your voltage is not constant, but varies with the time of day and the load on the system as a whole, the load on your local substation and even the load in your house. In the absence of an accurate meter, the best you can do is adjust the value over time so that the energy you record agrees with the readings of your electricity supplier's meter.
Re: use the right voltage
Thanks for your answers!
regards