Hello!
For some weeks, I have been using an STM32F769I-DISCO board as the centrepiece of a new industrial solution which enables us to know how much paper has been consumed by a studied machine. Therefore, firstly, an inductive sensor is used and generates a signal which corresponds to a certain quantity of consumed paper. This signal is injected to two analog inputs of the microcontroller: "A0" & "GND". Of course, there is always before a voltage reduction of this signal (indeed, the voltage of the sensor's signal is around 24V and, after using a voltage divider, the voltage of this signal turns out to be equal to approximately 2.63V, so lower than 3.3V).
However, I encountered a problem when I used this board inside a production area where some electric engines were activated. Indeed, through a test where the solution with the board had been deployed just over a production machine with an electric engine, some electromagnetic interferences seemed to be liable for an automatic incrementation of the counter developed in the microcontroller. For that matter, the voltage readers developed just before in the microcontroller showed there were some voltage peaks whereas the voltage was supposed to be equal to 0V at those moments. Those peaks were higher than the threshold value which is initially used to allow the incrementation of the counter.
Therefore, I really need your help about the devices I may use in order to protect the board from the electromagnetic disturbances. What kind of filter might I use? The useful signals of the sensor will never have a frequency higher than 40Hz.
I truly thank you in advance for your help!
Best,
Lleyton
