• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 79 subscribers
  • Views 1839 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Interfacing ACS712 with MSP430

Mr.Nischay Kumar V
Intellectual 505 points
Other Parts Discussed in Thread: MSP430F2012

Hello Forum,

Before posting my question, i tried searching the forum, but gave 0 results.

I have 20A, ACS712 Hall current sensor breakout board which i intend to interface with MSP430F2012.

ACS712 IC needs +5V and its o/p is Vcc/2 when not sensing any magnetic field, whereas Msp430 is powered with 3.3V.

A potential divider can be used to half the o/p voltage of current sensor,  will this cause accuracy loss ? i plan to use internal 2.5V as Vref.

Is there any other way to interface the current sensor to msp430 ?

Regards

Nischay

  • 0
    Guru 227245 points

    Mr.Nischay Kumar V said:
    A potential divider can be used to half the o/p voltage of current sensor,  will this cause accuracy loss ?

    Depends on what you consider to be an accuracy loss.

    The ADC10 has a resolution of 2.44mV/LSB. If you divide the input by 2, this of course means a resolution of 4.88mV/LSB on the original signal.
    But there's also an accuracy loss if you do not use carefully matched resistors for the divider (taking the inrush current of the ADCs sampling capacitor and the input impedance into account). Lower.value divider resistors reduce the effect of the ADC input but make a higher load on the sensor output. And cause a larger current consumption. So it is up to you to find the optimum value.

    Now the sensor signal output range likely won't reach 0V or 5V. If it is, e.g. always between 1 and 4V, you might want to divide the output by only 1.5 and shift it down by 1V before dividing. With an OpAmp. (it will also eliminate the influence of the ADC input impedance completely).

**Attention** This is a public forum