I have a problem with the formula for calculating Ph
PH = 7 - (2.5 - SensorValue / 200) / (0.257179 + 0.000941468 * Temperature)
I interfaced the 1130 with arduino having a 0-5v input, and from what I saw the 1130 has a 0-5v output, so they are perfectly compatible.
In formula, the value "SensorValue / 200" I replaced it with the arduino reading value (0-5v) and the temperature = 25 but the values returned have values from -1.90 to 15.92 ph and not 0-14ph , These values are also confirmed by calculating with the calculator.
Is the formula correct? If it is correct what is the reason for that?
Am I mistaken a few steps?
I hope to have been clear