What deviations during the calibration are usual and how are they connected to the temperature?
It is difficult to give a precise answer without information about the sensor, particularly the age of the sensor. Good sensors have deviations in the range from 0.02 to 0.05 pH levels when calibrating.
The input voltage differs for each sensor, as each sensor has its own individual properties. For the majority of our sensors, it is between -30 and +30 mV at pH 7.
Both input voltages (pH 7 and pH 4) are important when assessing the quality of a sensor. The greater the difference between these two values, the better the sensor and the precision of the measurement and control. The differences should be over 140-150 mV.
The temperature sensor should always be used during calibration. The pH level varies according to temperature, so that it is always best to measure the pH level with temperature compensation. The deviation is between 20 and 30 °C, 0.17 pH levels, and the relationship is nonlinear.