PROGRAMMING OF VRAE
4 - 17
4.4.5 Change LEL/VOL Span Gas
This function allows the user to select a specific LEL and/or
VOL gas to be used as the span gas during LEL/VOL gas
calibration. The LEL and VOL gases must be the same. For
the LEL mode, setting this gas lets the unit apply the proper
correction factor when calibrating to methane. For
Autorange mode, it also sets the cross-over concentration
where the unit switches from 100% LEL to the
corresponding volume % reading. Finally, it selects the
proper firmware linearization algorithm for different gases.
1. “Change LEL Span Gas?” is the next sub-menu item in
Table 4.3.
2. Press
[Y/+]
key. If a LEL sensor is installed or a
combination LEL/VOL sensor is installed and the sensor
is set to LEL mode, the display shows :
LEL Span=?
Methane
If in VOL mode, the display shows “Vol span = ?
Methane”. If no LEL/VOL sensor is installed, the
message “No LEL installed“ will appear.
3. If the user does not want to change the LEL or VOL span
gas, press
[Y/+]
key to accept the current selection and
exit this sub-menu.
4. If the user wants to select a different LEL or VOL span
gas, press
[N/-]
. Then use
[Y/+]
or
[N/-]
to scroll
through a list of gas names until a desired gas name
appears in the display; then press
[MODE]
to select the
new gas name.
