PROGRAMMING OF VRAE
4 - 10
4.4.2 Multiple Sensor Calibration
This function simultaneously determines the second point of
calibration curves for multiple sensors in the monitor.
A bottle of mixed standard reference gases is needed to
perform this procedure. The user can choose several gas
mixtures* to be used in multiple-sensor calibration.
For use in Autorange mode, the unit should first be
calibrated in LEL (or Autorange) mode to span the LEL
sensor, then switched to VOL% mode to span the VOL
sensor, and finally returned to Autorange. In VOL mode, the
calibration and measurement gas must be the same.
Snap in the calibration adapter over the gas inlet port of the
VRAE Monitor, and connect the tube to the mixed gas bottle
as shown in Figure 4.4.1.
1. Continuing from Step 4 of the previous section, the
display should show “Multiple Sensor Calibration?”
Press the
[Y/+]
key. The display shows all the pre-
selected gases for the mixed gas bottle and “OK?”
question (as shown below for PGM-7800). Press
[Y/+]
key to accept the multiple sensor selection and start the
calibration, or press the
[N/-]
key to modify the sensor
selection and go to Step 6.
CO
- - - -
H
2
S
LEL OK?
OXY
2. Turn on the valve of the mixed gas bottle to start the flow
of the span gas. Display shows “Apply Mixed Gas” and
will wait for the calibration gas to reach the sensor.
When the calibration gas has reached the sensor the
display will show “calibration in progress… 60” with the
countdown timer shows the number of remaining
