Use mirror sensortype for visualization: The visualization of O2 sensor data is still based on the three slots. To make the usage of these slots more transparent and easy "mirror" sensortypes have been introduced. These types may be used within the refresh to switch the source. E.g. if only one or two slots are used for O2 values the the third may be used for CO2 data. By using the mirror the datastream does no longer need to be manipulated (copying Co2data in variables named O2xyz).