AO2000 CONTINUOUS GAS ANALYZERS  |  OI/AO2000-EN REV. B  287
 
 
 
Uras26: Optical alignment 
Definition 
Optical alignment of the Uras26 analyzer module will minimize the asym-
metry on the detector of the incident radiation through the sample and ref-
erence sides of the sample cell. 
When should optical alignment be performed? 
An optical alignment must always be performed 
•  If the offset drift has fallen below the permissible range (50 % of the 
physical measuring range. 
•  After a component (emitter, sample cell, calibration unit/cell, detector) 
is installed in or removed from a beam path. 
How should optical alignment be performed? 
Each beam path in the analyzer module must be optically aligned separately. 
If there are two detectors in a beam path, the optical alignment should be 
performed in the rearmost detector (as seen from the emitter). During an 
optical alignment, beam path intensity is varied by means of mechanical 
apertures and, if necessary, by turning the emitter case. For this, the system 
housing must be opened. 
Detector arrangement 
11
2
1 1
2
1
3
1
42
 
Detector numbers correspond to the numbers assigned to the series of 
measurement components as shown on the module identification plate. 
Test gas 
During optical alignment the zero gas supply must be turned on. 
Emitter wrench 
An "emitter wrench" is required to rotate the emitter case. It is affixed to the 
analyzer module. 
Menu path 
MENU → Maintenance/Test → Analyzer spec. adjustm. → 
Optical adjustm.