I have built an own hardware to measure the energy production of my thermic solar system.
Actually i asume, the pump flow keeps constant, thus when the pump is switched on the esp8266 gets turned on equally. Then i am measuring the temperature difference with two sensors. With a little formula i can calculate the current power and i am transmitting the data to emoncms.org.
My problem is, that because the power supply of the esp is directly connected to the pump relay, i cant know when the esp gets switched off, so i can transmit a 0.
I assumed that this is no problem, because, when the pump is switched off i have no energy flow and no interest in the Temperature difference. But actually emoncms keeps the last saved value over the entire timeout until the esp is switched back on again, where actually my power should be 0.
Has there anyone an idea, how i can get a 0 power when my esp8266 gets switched odd and times out?
her you can see the flat parts of the graph