Live readouts are values that are taken up to 5 times a second (if you are collecting at a slower rate, the live readouts will be updated at the same frequency as the collection) and displayed with each column name in the second row of the toolbar next to the icon for the interface that the sensor is attached to.
You can turn live readouts on or off from the Experiment menu. You can also turn them on or off in the column options dialog. View the column options dialog by double-clicking the name of the column in the data table.
While live readouts are on, Logger Pro continually checks each device to see if sensors have been added or removed. When the application detects that a sensor has been added, it will add the appropriate sensor column. When Logger Pro detects that a sensor has been removed, it will remove the sensor column unless that column contains data. If you do not want Logger Pro to automatically look for changes in the sensor set up, you can prevent it by turning live readouts off.
Live readouts for calculated columns that are based on sensor columns are also displayed in the toolbar. You can turn live readouts on or off for a calculated column that depends on a sensor column via a checkbox in the column options dialog.
Calculated columns that depend on more than one point for their display (e.g. Velocity) will not report live readouts since a live readout is by definition a single value. However, while you are doing a data collection the live readout display will show the most recently collected point, and thus this type calculated column will show a value.
The Motion Detector makes a distracting noise when taking its reading, so by default its sensor column (Position) and calculated columns (Velocity, Acceleration) have live readouts turned off.