Servomex DF-130E, Руководство оператора

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26 DF-150E Options
oxygen reported by the analyzer will be less than the actual concentration. A
special heavy gas scale factor option is also available to allow the analyzer to
automatically correct the oxygen reading.
The analyzer is factory configured at the time of order for the customer
selected scale factor gas option. For gases lighter than nitrogen the available
options are Helium or Hydrogen Scale Factor. This option permits the
analyzer to be easily changed from measuring oxygen in a 100% nitrogen
background gas to measuring oxygen in a 0 to 100% light gas (He or H2 only).
There is a front panel adjustment control (labeled
% He in N
2
, or % H
2
in N
2
)
that allows the user to dial in the volume-percentage of the lighter gas portion
of the sample gas. If the control is turned to minimum the analyzer will be
adjusted to read correctly in Nitrogen. If the control is turned to maximum the
analyzer will be adjusted to read correctly in 100% hydrogen or helium
(depending upon the configuration ordered). For gases heavier than Nitrogen
the specific gas must be specified at time of order, and many heavy gases may
be accommodated, with a few limitations. Consult Servomex, prior to
ordering, for details. The scale factor adjustment control will be labeled with
the factory configured scale factor (example:
% N
2
in Ethylene ). Note that
for light gases the dialed in percentage is for the light gas volume, and for the
heavier gases the dialed in percentage is for the volume of Nitrogen. So, if the
control is turned to the minimum (0% Nitrogen) the analyzer will be adjusted
to read correctly in Ethylene. If the control is turned to the maximum (100%
Nitrogen) the analyzer will be adjusted to read correctly in Nitrogen.
When measuring oxygen in a background gas other than Nitrogen, with an
analyzer not equipped with the GSF option, see Table 4 for multiplier values
which the user can use manually to compensate for various gas diffusivities.
NOTE: If the sample contains an oxygen concentration near the high-end of
the instrument (e.g. 80 ppm on a 0-100 ppm unit), and consists of a light gas
background, the current generated by the sensor may be too much for the
electronics to source and will effectively put the instrument out of range. In
such a case, it would be appropriate to use an analyzer of the next highest
range (e.g. 0-500 ppm). Consult Servomex for application specific details.
7.11.1
Adjusting the Gas Scale Factor Pot for Light Gases
(He or H
2
)
1) Open the front door.
2) Locate the View Ref. Toggle switch. See Figure 13.
3) Throw the toggle switch upward to % H
2
in N
2
(or % He in N
2
, as
appropriate) and observe the front panel display. The number will be preceded
by a negative sign to differentiate it from an oxygen reading. Ignore the
decimal point as it will be in a different position depending on the selected
range.