Connection of ACS756 current sensor for AC current sensing

[hasanf]

Hi and good day,

I have a question regarding the connection of ACS756 current sensor to sense the current of AC load/ appliance. Let say, i wanna measure the current usage of my laptop, then how would i connect the sensor to the laptop?

My first guess was the "livewire" of the AC appliance should be connected to both ends of the ACS breakout board (at IP+ and IP-). However after some trials with microcontroller ADC, the readings were almost stagnant (no change in data). Is the problem caused by the connection or was it normal for AC current readings?

As the tutorial on the website is for DC connection (which I have successfully tried), could anyone show an example of connection for the AC connection? (I have gone thru the net and found none).

Thank you for your time and help!

[robosang]

Not sure about the connection because never use that sensor. But let me ask you a question. How much current do you think the laptop adapter require?

[shahrul]

How to connect current sensor is same like how to measure current using Multimeter. You need to connect in series with the measured current, so current flow throught it.

[hasanf]

Ok, now that I've done with the connection and thank God, i've got a list of reading data for sampling. Now comes to the next issue on how to convert the ADC values to a more meaningful amperes.

The data gives an analog trend as it is AC current sensor. The example is like this:

515
514
513
512
511
511
511
512
513
514
515

Then, based on these data, how could we convert them into amperes so that the ampere values could be used to calculate the power usage?

I've search on the internet, and found this formula Amps = ( Ain - 511.5 ) / 20.46 which was posted by a forumer in this forum: http://www.protonbasic.co.uk/showthread ... ect+sensor

Does anyone know how the formula is formed?

[majdi]

I just connect this ACS756050B, for 240AC with bulp 12watt. Vout give 2.5VDC without 240v given. When i supply with 240ac still same not much change. Its possible the current below 1A? ACS756 must at least > 1A then Vout will have some different value.