Chapter 3
Theory of Operation
P/N 79000035_SM, Version 1.5 3 - 23 Focus 30/35 Service Manual
Fig. 3-21 Tilt sensor in negativ position
The two pictures above are displayed in an overpowered way to give a better impression of the tilted
situation
The principle of the dual axis tilt sensor is to use a light beam that is reflected towards a free liquid
surface via an optical lens. A CMOS image area detects the inclination of the light beam in the
measuring direction and perpendicular to this direction.
The tilt sensor includes a PCB board for calculating levelling data. The data are sent to the Main
control processor board.
The tilt sensor is pre-calibrated and the correction data are stored in the sensor.
Vertical axis of instrument
Electronic board
Area sensor
Point LED
Silicon oil
Vessel
Prism
Optics
Prism