Bacharach Gas Pup, Инструкция

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Instruction 55-9002 13
Gas Pup
PPM Range
After the Gas Pup has been turned on, it
will default to its PPM range, showing
nothing or some portion of a bar graph
display. The range window will show a
pointer to the “PPM” flag for range defini-
tion. Any low levels of gas will be shown by
a moving bar graph, which is logarithmic
providing a much higher response at the
low end of the scale. No numerical display
is provided in this range, as its primary
purpose is to locate a small leak rather than
to measure a gas concentration. Full scale
on the PPM range is 2,500 PPM or 0.25% by
volume. 500 PPM is about mid-scale, while
1,000 PPM is about ¾ scale.
LO% (Low Percent) Range
When the gas concentration increases
beyond the upper limit of the PPM range,
the display automatically switches (auto-
ranges) to the LO% range, showing a two-
digit value with one decimal place. This
range of the instrument is used for detect-
ing gas concentrations that may approach
the explosive level. Natural gas may cause
an explosion if the concentration is around
5% by volume in air. This is referred to as
the Lower Explosive Limit (LEL) of gas,
and represents an extreme hazard. The
range indicator points to the “LO%” flag for
range definition. The reading will track
current concentration with a numerical-only display. This approach is
used to provide a numerical readout where readings are significant and
documentation of readings may be required. Auto switching from PPM to
LO% is instantaneous. Switching from LO% to PPM, however, may be
accompanied by the display momentarily flickering between the bar-
graph-only display (PPM range), and the numerical-only display (LO%
range). This flickering should be brief.
Operation
Figure 9.
Typical PPM Reading
Showing 500 PPM
Figure 10.
Typical LO% Reading
Showing 2.5% Gas