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Mottramlabs / MQTT-Power-Sensor

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Getting nothing but 11w readings #3

Open beercity opened 4 years ago

beercity commented 4 years ago

I just get 11W on the basic test sketch no matter what. If I connect the CT, I get 11w, if I disconnect I get 11W. If I remove the Wemos from the sensor board, still 11W

Sometimes I get 23W. But mostly 11W, and never anything besides these two.

Board issue? Code issue? Not sure.

Mottramlabs commented 4 years ago

Hi beercity I'm assuming you are using the basic test sketch and the 11 is in fact 0.11 Amps. That is the softwares quiescent value (which can be trimmed to zero in the code). Anyway this is what you would see if there is no current flow through the CT or it's not plugged in. You can check the signal from the CT with a multimeter set to AC volts connected across R1 the 22R burned resistor, typical values would be 169mV AC when a load of around 4.5A is present, only approximate value without calibration. Don't forget that the CT should be clamped across only one of the wires under test, either L or N but not both as this cancels out the signal. David

sw1970 commented 3 years ago

Hi Mottramlabs, when you say "can be trimmed to zero in the code", do you simply mean subtract the quiescent value from the measured amount? Thanks!

Mottramlabs commented 3 years ago

Hi sw1970 Yes you are correct, simply subract the quiescent value from the sensor. Simple way is to remove the CT from the wire under test. David