Metrohm NIRS XDS Process Analyzer – SingleFiber - Manual (Page 12)

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This wrench is made by Seekonk, and uses a 5/16”
end. It is calibrated for 8 in-lb.
The wrench “clicks” when correct torque has been
reached. It may feel more like a “detent” and the
open wrench end will be visibly angled. Do not
tighten beyond this point.
1.3 Single Fiber Information
Single fiber is composed of one 600-micron fiber, surrounded by
cladding to protect the fiber from abrasion and damage. A single
fiber is shown, compared to a “Micro-bundle.”
The dark spot at the center of the SMA connector is the fiber in
each type. Single fiber optic methods are preferred for clear to
moderately clear liquids, with cable runs of up to several hundred
meters.
The fiber must be ordered in lengths for the job.
Since there is one fiber for illumination (source)
and one for detection (return) the installation will
include two lengths of fiber sufficient for the
distances involved.
A site survey should be conducted before
ordering fiber optics. Once cut and terminated
with SMA connectors, a fiber cannot be
lengthened. When measuring, allow room for
gentle bends, plus a reasonable “service loop”.
Allowance for a service loop permits minor
repositioning of the fibers, should that be
required. The outer end of the fiber is marked
“START”.
Information about Single Fiber installation is given in section 6.0 of this manual. Follow instructions
carefully to avoid fiber breakage.
1.4 XDS Process Options
Multiplexed systems are used where several channels
are required. An optical switching device is used to
monitor the sample channels one at a time, in
sequence. (This is called time-division multiplexing.)
This is suitable for both micro-bundle and single fiber
systems. Any system with more than one sample
channel uses a multiplexer assembly as shown.