Model CXT-IR
CXT-IR Instruction Manual
Rev. 2.1
Page 26 of 48
3.4.3
Set Gas Type
The IR sensor has a slightly different linearization requirement for different groupings of target gases.
The two selections are:
•
%LEL and
•
%VOL.
The Set Gas Type menu function is a simple choice between these two gas type groupings.
NOTE
The default value for Gas Type is methane (%LEL).
The menu item appears as:
Set Gas Type
.
From the Set Gas Type and Range text scroll, hold the magnet over
PGM1
or
PGM2
until the arrow prompt
appears and continue to hold the magnet in place for an additional 3 to 4 seconds (until the display starts to scroll
%LEL / %VOL
). Swipe the magnet momentarily over
PGM2
or
PGM1
to change the selection until the correct
choice is displayed. Hold the magnet over
PGM1
or
PGM2
for 3 seconds to accept the new value. The display
will scroll
Type Saved
, then
Set Range
followed by the currently selected Range. Momentarily hold the magnet
over
PGM1
or
PGM2
to change the Range Selection until the correct value is displayed. Hold the magnet over
PGM2
for 3 seconds to accept the new value.
Move to another menu item by executing a momentary hold, or, return to normal operation via automatic timeout
of about 15 seconds (the display will scroll
Set Gas Type
4 times and then return to normal operation).
3.4.4
Set AutoSpan Level
Set AutoSpan Level is used to set the span gas concentration level that is being used to calibrate the sensor. This
level is adjustable from 5% to 95% of range. The current setting can be viewed in View Program Status.
The menu item appears as:
Set AutoSpan Level
.
From the Set AutoSpan Level text scroll, hold the magnet over
PGM1
or
PGM2
until the arrow prompt appears
and continue to hold the magnet in place for an additional 3-4 seconds (until the display starts to scroll
Set
Level
). The display will switch to
XX
(where XX is the current gas level). Swipe the magnet momentarily over
PGM2
to increase or
PGM1
to decrease the AutoSpan Level until the correct level is displayed. When the
correct level is achieved, hold the magnet over
PGM2
for 3 to 4 seconds to accept the new value. The display
will scroll
Level Saved
, and revert to
Set AutoSpan Level
text scroll.
Move to another menu item by executing a momentary hold, or return to normal operation via automatic timeout
of about 15 seconds (the display will scroll
Set AutoSpan Level
4 times and then return to normal operation).
3.4.5
Set Gas Factor
Because of the CXT-I
R sensorꞌs almost universal response to combustible hydrocarbon gases, the CXT-IR
sensor can be configured and calibrated to detect a variety of combustible gases. The detected gas is referred to
as the "target gas" and the span calibration gas is referred to as the "cal gas". In cases where the cal gas is
different from the target gas, the Set Gas Factor menu function is used to maintain accuracy. This feature allows
for a significant degree of flexibility in the detection and span calibration process.
NOTE
The default value for Gas Factor is 1.0. This would be used when the target gas is the same
as the cal gas.
