Vaisala HMW90 Serie Guide Rapide page 19

Trimmer Adjustment (CO )
2
Transmitter models with CO measurement
2
have an inlet for calibration gas. Supply the
calibration gas with a known concentration
(for example, 1000 ppm) to this inlet using
a 3 mm inner diameter silicone tube and a
0.4 l/min flow.
Turn on the gas flow and wait for three
minutes for measurement to stabilize.
If you are adjusting without calibration gas,
avoid breathing on the transmitter.
You should only adjust the transmitter
when the CO reading is stable.
2
Rotate the CO trimmer slightly during
2
normal measurement. If the trimmer is not
centered, you see the trimmer centering
screen first. Simply turn the trimmer to the
center and wait for the progress bar to
EN
complete.
In the adjustment screen, turn the trimmer
to set the desired correction. To commit
the change, stop turning the trimmer and
wait. The transmitter will show with a text
screen if the adjustment was successful, or
failed due to an unstable CO reading.
2
As with the RH and T adjustment, repeated
trimmer adjustments are cumulative. Wait
for a few minutes between adjustments to
allow the CO reading to stabilize.
2
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