Vaisala GMP231 - Manual (Page 75)

Chapter 6 _______________________________________________________________ Maintenance
VAISALA ________________________________________________________________________ 73
Calibration and Adjustment
Calibrate and adjust the CO
2
measurement of the GMP231 as needed.
Before starting, read through this section completely so that you are
aware of your options, and the main factors that affect the result.
NOTE Performing an accurate calibration and adjustment takes some time and
preparation. Instead of doing it yourself, you can also have a Vaisala
service center calibrate and adjust your GMP231. For contact
information, see section Product Returns on page 84.
NOTE Calibration means comparing the GMP231 to a known reference, such
as calibration gas or a reference instrument. Correcting the reading of the
GMP231 so that is measures accurately is referred to as adjustment.
Calibration Setup
GMP231 is designed to be calibrated while it remains installed through
an incubator wall. If you calibrate the GMP231 without it being installed,
note the following:
- If you are using a calibration gas, prevent it from entering the
electronics housing of the GMP231. Otherwise it will diffuse through
the probe to the sensor and alter the CO
2
reading.
- Make sure the PTFE filter is in place when performing calibration.
- If you are using the calibration adapter accessory to feed the
calibration gas to the sensor, note that you must have the silicone plug
and the PTFE filter installed on the probe. Without both of them in
place, the calibration adapter will not function properly. Vaisala
recommends replacing the silicone plug and the PTFE filter before
calibration.
1403-147
Figure 20 Inserting the Calibration Adapter over the Filter