How does pressure affect the measurement for the SPECTRACAP^® oxygen sensor?

Operation of the SPECTRACAP^® sensor beyond the specified operating pressure range of 800 to 1400 mbar absolute will result in additional measurement error. Pressure affects the measurement through a phenomenon known as pressure broadening. Increasing the pressure of a gas containing oxygen changes the shape of the oxygen absorption lines and reduces the tunable diode laser (TDL) absorption signal per gas molecule. In the SPECTRACAP^® sensor this phenomenon is used to compensate for the ideal gas behavior that affects oxygen concentration readings when barometric pressure varies. Therefore, in most applications no barometric pressure compensation is needed.