PPM–400ST Formaldehyde Meter Operation Manual
from the instrument. Replace the end plugs in the
Calibration Standard securely.
5. Wait for the sample to complete and the
concentration to be displayed. Refer to Section 3.1
for details.
6. Refer to the look-up table printed on the
Calibration Standard and use the thermometer
reading to find the expected concentration. If the
displayed reading is within 5% of the value shown in
the table, then no recalibration is required.
Otherwise follow the procedure in Section 4.4.
Leave the instrument switched off for at least 5
minutes to recover before commencing another
atmospheric analysis or calibration adjustment, for
more details see Section 3.2.
4.4 Calibration Adjustment Procedure
To see whether a full recalibration is required,
perform a calibration check first, as described in
Section 4.3.
Temperature
Equilibrium
Place the instrument, a thermometer and Calibration
Standard together in a place where the temperature
is stable for at least one hour before commencing the
calibration check procedure to allow thermal
equilibration.
Sensor Check
Before carrying out a calibration check, the sensor
must be clear of formaldehyde vapour from any
previous samples. See Section 3.2 for further details.
Procedure
1. Switch the instrument on by pressing the
%
button
once. Wait for the display to show
0.00
2. Place the Calibration Standard and thermometer
on a work surface. Remember to handle the
Calibration Standard by the yellow end caps to avoid
heating the tube. Remove both end plugs.
3. Insert the instrument nozzle into the sampling end
of the Calibration Standard (refer to
fig 1.2
). To
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