Cerbo GX Analogue input calibration

[Daves12345]

We have 10 of the Cerbo GX devices in our network. We use the analogue inputs for room temperature monitoring. 9 of the Cerbo GX show a significant calibration error with just one being very precise. All 4 analogue inputs are the same on each unit. To test the calibrations I have used an accurate DC power supply to input voltages of 2.73V and 3.73V. The voltages shown from the 9 problem Cerbo GX are about 0.1V high which varies a bit between units. So we have one that shows 2.82V and 3.87V for example. The voltages should give us 0C and 100C temperature readings but instead give 9V and 113C on this unit. We can use an offset to partially correct this by subtracting 10 from the temperature reading. The scale setting does not help us as the resolution is not good enough. But messing with the offset and scale settings is trying to correct a problem that should not be there. Is there a way to calibrate the analogue inputs? I am guessing it is hidden somewhere if it is.