Reading voltage from ACS712

Hai,I tried to read AMPS rating for an induction motor using microcontroller.
Specification of the motor is 230VAC and 1.67A during full speed operation.Checked the current rating with clamp meter also.Its 1.55A to 1.65A reading are observed.

I connected ACS712/5A module across the phase wire to motor and measure the OUTPUT from module.It's showing 370mA as maximum value by selecting mA in multimeter.

I have to interface the module's output to PIC controller to measure the AMPS rating.

So I tried the above OPAMP circuit to amplify the value from module to interface with MCU.But their is no output from the amplifier circuit.It always showing zero value.Without connecting to MCU also showing zero value while checked with multimeter means.

How to solve this issue..?

Hi,

I connected ACS712/5A module across the phase wire to motor and measure the OUTPUT from module.It's showing 370mA as maximum value by selecting mA in multimeter.

Click to expand...

ACS712 is voltage output.
Don´t measure current, since this will cause short circuiting the ouput and may immediately destry a voltage output device!

Read the ACS712 datasheet. (Btw: the datasheet says at the Absolute maximum ratings. 10mA output current. Any value beyond this absolute limit may kill the device!!)
Learn how to measure voltage and how to measure current.

*** Circuit:
What do you expect it to do?

* it adds negative offset (I don´t think it´s useful)
* it adds gain (do you need this)
* it makes simple - very unprecise - rectification...
* I even doubt the ouput filtering makes sense.

Klaus

The purpose of the OP circuit isn't clear. It's neither well suited to amplify the instantaneous ACS712 output nor to get an AC current measurement.

While connecting the DC load,It's easy to read the amps by output values.
But when AC load is connected means there is no changes in output pin,but while measuring with multimeter in AC means,we can get the voltage.For interfacing with the microcontroller, I tried to connect the bridge rectifier with ACS712 but there is no use.

How to measure the voltage in MCU generate by ACS712 while connecting with AC load.

There are basically two methods to process AC (current or voltage) measurements.

- Use a precision rectifier (producing average rectified value), RMS detector or peak detector circuit, depending on the measurement purpose. Read its output with ADC. Circuit filter time constants have to be dimensioned according to AC frequency, accuracy and response time requirements

- Read the instantaneous value with ADC, generate average rectified, RMS or peak measurement in software. ADC rate must allow sufficient oversampling of the AC signal.

i not try.
https://www.sunrom.com/p/current-sensor-20a-acs712
https://forum.arduino.cc/index.php?topic=473263.0