The probe limits the amount of adjustment that is allowed to the CO2 measurement. The maximum correction that you can apply is 1000 ppm + 25 % of the probe’s uncorrected reading. Previous user adjustments do not affect this limit (the correction is not cumulative). This feature limits the possible error introduced by incorrect adjustment.
For example, if you are adjusting using a 5 %CO2 calibration gas (50000 ppm), the maximum correction you can apply is approximately 13500 ppm. Attempting to apply a greater adjustment will fail. Notification of failure from the probe depends on the interface you are using for adjustment.