In build ADC

Hi

iam using In build ADC Atmega32 controller .

How to interface 0-10V signals to ADC input of the controller.

What ground I have to connect for sensor signal (-ve) either digital ground or

analog ground

What precautions I have to take while connecting analog signal to the micro

controllers(In build ADC ).

Regards

chandu

If you use 5V for the Mega32 and as AREF too, then you have to use voltage divider on the ADC inputs to limit the max voltage on the input to be less than 5V at all time. If you use a fixed resistor and a variable resistor to ground as divider, then you can trim variable resistor to make the ADC gives 1000 counts when you inject a 10V DC signal. Your resolution is 10mV.

If the signal source is of high impedance, you will also need Opamp to buffer and scale the voltage down accordingly.

There is no analogue ground pin on the Mega32, just GND. You should connect the two ground pins to the input signal (-ve) and you cannot measure negative signal or non-ground referenced input.

short

Thanks for the reply

What ground I have to connect for sensor signal (-ve) and volatage divider

ground , either digital ground(controller) or analog ground (sensor).

If i want short analog ground and digital ground, how to short both

gounds together.

Regards

chandu