Installation
24
GasEye Cross Duct SG and MG
Operating instructions, 05/2021
The central unit (transmitter unit for Multi Gas version) and the receiver unit need to
be aligned with respect to the axis of symmetry of the flange.
During the installation of the GasEye Cross Duct instrument, the laser and the
photodetector must be aligned to the optical axis of the sensor pair. Note that each
sensor has an optical axis of its own which is its axis of symmetry. In addition, the
sensor body is at an angle to this axis. The reason for this is that the laser beam
passes through two wedged windows before it enters the receiver. Each wedged
window will refract the beam at an angle of approximately 1.5°.
Optical path length determination
For proper performance of the instrument it is crucial to determine the correct optical
path length. User must enter the actual value of the measuring path length in meters
in the GasEye WebServer (Refer to Chapter 8.2 Parameters tab). The measuring
path length is defined as the distance between the ends of purging tubes. Please refer
to Figure 10 for correct determination of the path length.
Figure 10. Schematic drawing of the optical path length determination.
