How to read the sensor value from ACS712 Low Current Breakout

[Prince_Eakdanai]

Hi, I would like to measure the consumption value of the lamp, Size 100W, 220Vac (0.45A).

I have noticed that the output from the sensor IC is Vcc/2 (~2.5 V) if there is no current.

so, @0A -----> output from sensor is 2.5Vdc

If the sensor output is linear with the current input.

      @0.45A -----> probability output from sensor is 2.725Vdc (Vo = (0.45+5)/2)

However, when using a digital multi meter to measure Vo pin (Swith On).

Found that the Vo at 2.5Vdc same and no change.

And try ro get Vo value fron ACS712 sensor connected to the Analog Input of the Arduino board.

And read the value via Analog Read Pin Fubction through the Labview program.

Found that while the lamp is switched off, Waveform chart that reads the value from the Analog Read Pin to remain at 2.5Vdc.

However, when the switch to the light bulb work.The Value read from Waveform chart to swing up and down from about 2.1 to 2.8Vdc.

Preliminary, I think that this may be due to measuring AC Current.

If to measure load and dc curcuit, output that is linear with the input.

Or a problem with the sensor.

Please advice me how to measuement for this case.

Best Regards,

Prince