Yokogawa In-Situ Gas Analyzer TDLS200 - Manual (Page 74)

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IM 11Y01B01-01E-A 6th Edition :Feb 13, 2013-00
<6. BASIC OPERATION>
6.3 Non-Process Parameters
Non-Process Parameters is the Yokogawa Laser Analysis Division term used to define regions of the optical path
that may be purged with a gas containing the actual target (measured) gas. The most common application of this
is to use Instrument Air (~20.9% O
2
) as the purge gas for analyzers measuring Oxygen in the process.
Another common use of this feature is “Line Locking” whereby some target gas (typically %CO for CO/CH4
combustion analyzers) is locked into the validation cell at all times and therefore its absorption contribution must
be accounted for.
The valve functionality of Line Locking has four stages as shown below.
Figure 51