Yokogawa In-Situ Gas Analyzer TDLS200 - Manual (Page 75)

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IM 11Y01B01-01E-A 6th Edition :Feb 13, 2013-00
<6. BASIC OPERATION>
If measuring CO in the process gas and the purge gas is Instrument Air, then these parameters are not applicable
because the CO concentrations typically found in Instrument Air are below practical detection limits.
In order for the analyzer to measure correctly under these purge conditions, the analyzer must know the correct
parameters such that the measured output value has been compensated i.e. the oxygen in the purge gas has
been taken into account when determining the process oxygen concentration.
Oxygen present in the Instrument Air purge may exist in several section of the optical path including:
• Inside the Launch unit body, laser module section
• Inside the Launch unit body, online validation cell
• Inside the Launch unit alignment flange
• Inside the launch side process nozzle (and valve)
• Inside the Detect unit body
• Inside the Detect unit alignment flange
• Inside the Detect side process nozzle (and valve)
It is important that these dimensions are known as they will need to be programmed in – if in doubt, please
contact Yokogawa Laser Analysis Division.
Calibration – The analyzer MUST be calibrated (Zero and Span) as
per the normal methods outlined in the standard User’s Guide. When performing a Zero Calibration,
ensure that the entire optical path is purged with Nitrogen. When performing a Span Calibration, ensure the
correct procedures are followed!