What is automatic temperature compensation (ATC) in pH meters?

When measuring pH using a pH electrode the temperature error from the electrode varies based on the Nernst Equation as 0.03pH/10C/unit of pH away from pH7. The error due to temperature is a function of both temperature and the pH being measured.

Temperature compensation can be achieved manually or automatically. Manual temperature compensation is usually achieved by entering the temperature of the fluid being measured into the instruments menu and then the instrument will display a “Temperature Compensated” pH reading. Automatic temperature compensation requires input from a temperature sensor and constantly sends a compensated pH signal to the display.

Automatic temperature compensation is useful for measuring pH in systems with wide variations in temperature.

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