Analog to digital signal block diagram confirmation

Discussion in 'The Projects Forum' started by nudmat, Feb 25, 2015.

  1. nudmat

    Thread Starter New Member

    May 27, 2014
    Good day to all,
    Please i need your Support in helping me to confirm if the block diagram i attached to this thread is correct. I want to read an analog Signal from a sensor and convert it to a digital Signal with the help of an in-built ADC in a microcontroller. I am not sure if the resistor i connected to the ADC Input is all i need to get the ADC of the microcontroller to receive the accurate Signal from the sensor or if i still need other components.
    The operating voltage of the microcontroller is 5V
    The Output analog voltage Signal from the sensor is from 0V to 5V
    The Output analog current Signal from the sensor is from 4mA to 20mA
    If the sensor outputs for example 4mA,then the Input voltage to the ADC of the microcontroller will be 1V using the 250 Ohms resistor. I would be glad if somebody could help me confirm if this Arrangement is correct. Once again thank you for the Support. Best regards.
    NOTE: All other Connections with respect to the microcontroller have been taken care of. The only part i need help is the ADC section.
  2. MrChips


    Oct 2, 2009
    Give us the part number of the sensor or post a link to the datasheet.
  3. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    Is this sensor a 4-20mA loop device? If so, 250 ohms is an acceptable value (though I would use a lower value to detect faults).

    4ma gives you 1V, 20mA gives you 5V so that plays well with the A2D.

    I don't know what rules the block diagram follow but as a schematic the resistor is not connected correctly.