Should not be a linear relationship in theory, in the second part is where the problem, consult bosses

CodePudding user response:

Suggest the original poster to verify the ADC reference voltage, see the second half of this figure you feel you've input analog voltage is greater than or equal to the reference voltage,

CodePudding user response:

Such as your range is 5 v, corresponds to 1024, when the input is greater than 5 v, the transformation output is 1024, will not increase

CodePudding user response:

In the second part is equal to the full, if the reference voltage 3.3 V, then measured is more than 3.3 V, 3.3 V, and the battery can't charge after go in

CodePudding user response:

Is the scope of your range of plus or minus 2.048 V, so when the voltage is greater than 2.048 V, the sampling is not accurate, recommended range of plus or minus 4.096 V instead

CodePudding user response:

Can you tell me the original poster know the answer now?? I also met this problem!!!!!

CodePudding user response:

1. Suggest take the adc reference voltage,
2. The input analog voltage can consider to use precise resistance partial pressure,

CodePudding user response:

Behind the numerical change no longer is the point of reference voltage sampling voltage up to the AD, lead to ADC after full scale output changes no longer,

CodePudding user response:

Give ADS1115 VDD voltage is too low, such as 3.3 V, so that when voltage close (3.3 0.7), there are words characteristics of leakage,
So you got a top is 0.7 V (small current 0.9 to 1.2 V) top, similar voltage characteristics, need improve ADS111 VDD voltage! For example, 5 v