I want read the voltage from an electrochemical battery and send it to my PLC in order to do some automation (average value is around 1.2V, and I need an accuracy better than 100 microvolt). I am using ADS1115 (there is a post about it here). I have now a pretty stable signal, however I want to add a filter for the oversampling frequency at the input just as a good practice and also in order to get the smoothest reading as possible.
The point is that I am not sure of which data rate should I select for the ADC. As my DC signal changes very slowly (for example, in two seconds, it changes from 1.2020 V to 1.2010V. I know this because I have a BTS system connected to it to cycle the battery and to measure everything too) my guess is that a data rate of 8 sps would be enough. Also I have connected a multimeter and also an osciloscope to see the look of the DC signal). But if I select this data rate and I decide to implement an RC filter then the oversampling frequency would be very low and it would be difficult to get the capacitor values for it (I am doing differential measurement).
So my questions are:
- Which data rate to select for this DC signal?
- Is a low pass passive RC filter the way to go?
- What values would be suitable for a coherent data rate and RC filter to build it in a breadboard?
- Is there any already existing LPF to perform this to avoid implementing the RC filter?
