Vaisala GMP343 - Manual (Page 65)

Chapter 5 __________________________________________________ Calibration and Adjustment
VAISALA_______________________________________________________________________ 63
concentration of nitrogen mixture gases is usually 0 %. If necessary,
adjust the values. For example:
P 1000.3
RH 0
O 0
For more information on compensations, see section Temperature,
Pressure, Relative Humidity, and Oxygen Compensations on page 45 .
Measurements in Reference Gases
1. If your GMP343 is the diffusion model, remove the filter cover and
place the calibration adapter onto the probe.
2. Let the device warm up for 30 minutes to achieve full calibration
accuracy.
3. Turn on the calibration mode by giving the command CALIB ON.
This changes some of the transmitter parameters for the duration of
the calibration.
CALIB ON
4. Connect the reference gas to the inlet of GMP343 transmitter and let
the gas flow for 5 minutes (about 0.5 l / min).
5. To output the measurement result, key in the command R. Check that
the reading is stabilized and write down the CO
2
reading (ppm). Enter
command S to stop outputting. For the best calibration result, it is
recommended to calculate an average of 20 measurements instead of
a single reading.
6. Shut off the reference gas flow and remove the tubings from the gas
bottle. When calibrating at several points, connect the other gases to
GMP343 similar to the first gas and carry out the measurements as
instructed above (steps 6 and 7).
7. After measurements turn off the calibration mode by giving the
command CALIB OFF (this reverts to the original transmitter
settings).
CALIB OFF