FAG Detector III User Manual page 204

Units
In the Units dialogue window, you can specify the options for scaling units used
in the diagrams.
In the Unit selection area all measurement types are listed. Besides the
preferred unit and an information about scaling are shown. The preferred unit
cannot be changed at ISO and US units. The automatic scaling is activated by
default at this profiles.
By selecting "custom" you can assign the preferred unit depending on the
measurement type. Here the automatic scaling can also be set.
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