Chapter 3
Theory of Operation
P/N 57150002, Revision 5.0 3 - 87 Trimble S, VX, SPS & RTS Service Manual
F
Servo focus
This instrument is equipped with an motorized focusing device. Turning the focus control knob
controls the servo motor, which modifies the location of the moving lens and hence provides focusing
control, as illustrated below. The focus knob on the right hand site of the Alidade is connected to a
servo motor built into the telescope unit.
Location of servo focus
Fig. 3-79 Servo focus location
Technical Specifications
• Focusing range 1,5 m to infinite
• Movement of lens maximum speed of 10 mm/s
• Length focusing track 19,5 mm
• Resolution servo focus 1 step 50 m
Function description
The servo focus drive is placed in the telescope behind the eyepiece and is reached from the upper
side in second face.
Focusing motor
Shifting lens
Control board