If there are no preset values introduced, the preset value is zero (here 0.000).
V.2 Reference mode
V.2.1 Selection of the reference
Press quickly the [mode] button.
The new reference is selected.
V.2.2 Hold the measure
Press quickly the [set] button.
Comments: The displayed value is automatically transmitted through the interface OPTO-RS232. When no external connection is made, displayed value remains
frozen.
(See also instruction manual under connector OPTO-RS).