Analog to digital signal block diagram confirmation

[firstoption]

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.

 

[FvM]

It's correct to use a 250 ohm shunt to convert 4-20 mA to 0.5-5V. But the resistor isn't connected correctly in your diagram. It has to be connected between ground and analog input pin with the sensor output current feed to junction of resistor and analog pin. You should also include the ground connection of the sensor in your diagram and clarify if it needs a supply voltage from your circuit and how it's connected.

It may be suitable to add protection means for the processor if there's a possibility that the sensor can drive higher currents than 20 mA.

The digital output may be described more specifically in the diagram, e.g. serial UART, parallel data bus etc.

 

[ravindragudi]

Agree with FvM.

Here is a link where the 4 to 20mA receiver design is explained in simple way. May be helpful for you in your project.
**broken link removed**

 

[firstoption]

Thank you all for taking the time to go through my question, I really appreciate your sense of understanding. I made some adjustments to my block diagram based on the explaination giving by FvM. I would be glad if you could help me have a look at the new block diagram so as to confirm if i connected the resistor properly.

The sensor is a complete System,it is on a separate board while the microcontroller is on another board , so i am connecting the analog Output Signal from the sensor to the microcontroller through a 2-pin connector.Sir i would like know if the way i connected the sensor GND to the microcontroller GND is correct. In Addition to my block diagram,i have also included the datasheet of the sensor. Once again thank you for the Support.

 

[FvM]

It's good this way.