PROGRAMMING & CALIBRATION
3-9
True Concentration = Correction Factor x Monitor Reading
Correction factors allow measurement of a specific gas while
using a different gas for calibration.
The Q-RAE Plus stores several different correction factors for
the LEL sensor in a compound library that can be accessed
through the Change LEL Span Gas and Change LEL Gas
Selection Menus.
Note
: Using the correction factor provides an estimate the
target measurement gas. For greatest accuracy, it is necessary
to calibrate the LEL sensor directly with the target gas.
3.6.1. Change LEL/VOL Sensor Type
Note:
Combination LEL / VOL Sensor is not available in North
America.
This programming sub-menu applies only to monitors with the
combination LEL/VOL sensor installed. This sensor can be
setup to measure combustible gases by percentage of the
Lower Explosive Limit (LEL), or it can be set up to measure a
variety of gases in percent by volume (VOL) levels up to 100%.
The sensor can be set up to automatically switch from %LEL to
%VOL when methane is selected for both sensors. Use the
Keystrokes from Table 5 to switch between LEL, VOL, and
Auto-ranging modes.
CAUTION!
Auto-range should be selected only when the methane is used
as the calibration and target gas.
3.6.2. Enable / Disable Sensor
This function allows the user to selectively enable or disable
individual sensors in the Q-RAE Plus monitor. When a sensor
is disabled, the unit will not datalog or display gas
concentrations of that type. Use the keystrokes in Table 5 to
