ADC INJECTED Wrong values reading

[majd-ghadab]

Posted on June 28, 2018 at 22:18

Hello everyone

i have a question, i am using 3 Ranks ADC injected mode for reading potential resistors..

the problem is when ever i change one value it affects the other channel reading.

example

channel 1

 reading is 1.3v

channel 2

 reading is 1.5v

channel 3 reading is 1.6v

changing only resistor value on channel 1 to 2.9v makes the following:

channel 1

 reading is 2.9v

channel 2

 reading is 1.7v

channel 3 reading is 1.7v

why when i change one value the others are affected !! or the second one affecting the third !

code is :

while (1)

{

HAL_ADCEx_InjectedStart(&hadc1);

HAL_ADC_PollForConversion(&hadc1,100);

u[0]=((float)HAL_ADCEx_InjectedGetValue(&hadc1,ADC_INJECTED_RANK_1))*3.0/4096.0;

u[1]=((float)HAL_ADCEx_InjectedGetValue(&hadc1,ADC_INJECTED_RANK_2))*3.0/4096.0;

u[2]=((float)HAL_ADCEx_InjectedGetValue(&hadc1,ADC_INJECTED_RANK_3))*3.0/4096.0;

HAL_ADCEx_InjectedStop(&hadc1);

sprintf(str, '%.2fv %.2fv %.2fv ', u[0], u[1], u[2]);

LCD_SetPos(0,0);

LCD_String(str);

HAL_Delay(200);

/* USER CODE END WHILE */

/* USER CODE BEGIN 3 */

}

#injected-adc

[IMaji]

Same problem.

Who knows why and how to fix it?

[Tesla DeLorean]

Perhaps use a sample time setting commensurate with your ability to change the charge level on the sampling capacitor?

[IMaji]

Here is the mine configuration. I changed Sample time value but no changes.