Spectra Precision Focus 30 - Distance meter unit F30; Location of Distance meter unit; Technical specification

Chapter 3
Theory of Operation
Focus 30/35 Service Manual 3 - 10 P/N 79000035_SM, Version 1.5
Distance meter unit F30
The Distance meter unit (EDM) is a direct reflecting distance meter based on the phase shift method.
The optical Transmitter unit transmits a modulated light beam to the target. The optical Receiver unit
detects the returning light reflected from the target. The Receiver unit measures the phase difference
between transmitted and received light and calculate the distance.
Location of Distance meter unit
Fig. 3-8 Location of Distance meter unit
Technical specification
• Light source: Laser diode 660nm
• EDM beam divergenz horizontal: 0,4mrad
• EDM beam divergenz vertical: 0,3mrad
• Principle: Phase shift
• Accuracy Prism mode 2mm + 2ppm
• Accuracy DR mode 3mm + 2ppm
Receiver
fiber
Reference
fiber
Greywedge with
internal/external
Switching motor
EDM Mirror 2
EDM Mirror 1
Transmitter
prism
Receiver
diode
Transmitter
diode