50 • Chapter 5: User Mode and Calibration
GasWatch 3 for CO and O
2
4. Press and release POWER/MODE. The display shows the gases assigned to Cylinder A
and their assigned calibration values (see pg.54 if the calibration values do not match the
calibration gas cylinder’s concentrations). The bottom of the screen alternates between
“E-CAL” and “CYL A”.
5. If necessary, use AIR to scroll to the Auto Cal screen for the gas(es) you want to calibrate.
As shipped from the factory, CO and O
2
are assigned to Cylinder A.
6. Make sure the GasWatch 3 has been turned on for at least 45 seconds before
continuing.
7. Press and release POWER/MODE.
8. The gas readings flash and the bottom of the screen says “GAS IN”.
9. Turn the regulator knob counterclockwise to open the regulator.
10. Once the gas reading reaches 10% of the auto calibration value, the screen starts counting
down from the time specified in the
E-CAL
User Mode item. In the example below,
E-
CAL
is set to
60
seconds.
To back out of the gas application screen without performing the calibration, press and
release AIR and POWER/MODE together.
If the reading never reaches 10% of the auto calibration value, press and release POWER/
MODE to fail the calibration.
11. At the end of the countdown, the instrument makes the span adjustment.
CYL A
0.0
%
50
ppm
E-CAL
0.0
%
50
ppm
GAS IN
20.9
%
0
ppm
APLY 60
20.9
%
0
ppm
CAL 60
20.9
%
0
ppm
