Current consumed by an motor with PWM Signal in.

[sygma22]

reading of the current consumed by an engine crossed by a signal PWM:

Ex for has Pic18F7620 gold other 12Volts 9 Khz 50% Duty: how to use the function ADC.read or ADC.read.median….

Thank you d' avence for an answer.

[rmteo]

You first need to convert the motor current to a voltage before the ADC can read it. The simplest way is to put a current sense resistor on the low side (referenced to ground) of the motor. Let's say you want to know when the motor current exceeds 5A. If you use a 0.5 ohm resistor, the voltage across it will be 2.5V (0.5x5) and you can measure this voltage using the ADC.

There are more efficient ways of doing this though. In the example given above, a lot of power, 12.5W (5x5x0.5) is wasted in the resistor. You want to keep the sense resistor value as small as possible - I like to keep at 0.01 ohm or less. Also, placing the resistor on the low side has disadvantages - it generally preferable to have the current sense resistor on the high side.

[sygma22]

Thank you very much...

I will try with adc.readmedian and i will inform you the best choice.