measurement of currents using ACS172 on STM32f407VG

[VTOL_Aviations]

Hai ,

my name is Dattu i am working on a project which involves measurement of current using ADC on STM32f407VG to achieve this i am using a 30A ACS712 sensor i have interfaced the sensor but when i am running the program i am getting a constant value like 1 or 0 so any can help with the interfacing issues i am not using a divider circuit even if i use i am getting same issue

Thankyou in advance

[Ozone]

>... measurement of current using ADC on STM32f407VG to achieve this i am using a 30A ACS712 sensor ...

I am not sure if this sensor is a good choice.

The datasheet states:

>... 66 to 185 mV/A output sensitivity ...

For a F407 drawing less then 200mA, the sensor range seems a bit (2 orders of magnitude) off.

On top of that, the datasheets states "not recommended for new designs".

[TDK]

What value are you expecting? How much current is going through the sensor? Maybe that's just what the reading actually is.

[waclawek.jan]

Did you measure the output of the ACS712, using a multimeter, or better, oscilloscope?

JW

[VTOL_Aviations]

I am using a digital multimeter to measure the output i am able to see output value as 0.59/0.65 constantly

[VTOL_Aviations]

do you mean that i cannot use ACS172 sensor on stm32f407vg board and in that case do i have any other alternative to measure current on stm32f407vg like any sensors or do i need to build my own circuit

thankyou

[VTOL_Aviations]

the output which i expect should vary according to the change in voltage (or) a constant voltage with variable load i have tried both the ways in case if this sensor is not appropriate for this task how can i proceed further my final aim is to measure current across load using adc on stm32f407 vg board

[Ozone]

Do some rough estimations. A STM32F407 draws about 100mA, which is 0,3% of the sensor's range.

This gives you about 7..18mV sensor output signal, which uses at most 4 bits of the 12-bit ADC signal of 3.3V.

I would call this a bad choice.

[VTOL_Aviations]

do i have any alternatives if so please guide me

[waclawek.jan]

So the the ADC is not set up properly. In debugger, check in respective GPIO_MODER if the pin is set tp Analog. Read out and check the ADC registers.

JW