User's Manual

44 - K4 b
2
User Manual
Gas calibration procedures
The system can be calibrated according to the following procedures:
1. Room air calibration
2. Reference gas calibration
3. Delay calibration
4. Turbine calibration
The Room air calibration, forced by the system before every test, consists of a sampling
room air. It updates the baseline of the CO
2
analyzer and the gain of the O
2
analyzer, in
order to match the readings with the predicted athmospheric values (20.93% for O
2
and
0.03% for CO
2
).
The Reference gas calibration, recommended to be carried out daily, consists of
sampling a gas with a known composition (i.e. 16.00% for O
2
and 5.00% for CO
2
) from
a calibration cylinder, and updating the baseline and the gain (span) of the analyzers in
order to match the readings with the predicted values (i.e. 16.00% for O
2
and 5.00% for
CO
2
).
The Delay calibration, recommended to be carried out ones a week or whenever the
sampling line is replaced, is necessary to measure accurately the time necessary for the
gas sample to pass through the sampling line before being analyzed.
The Turbine calibration, recommended to be carried out quarterly, consists in measuring
the volume of a 3 litres calibration syringe and in updating the gain of the flowmeter in
order to match the predicted value.
Running the Calibration program
Start the program and choose Calibration from the Test Menu. The software runs the
Calibration software and the main menu changes accordingly.
Log file
The program creates and updates as default the calibration log file, containing the
conditions and the results of all the calibrations performed by the user.
To access the file select File/Report File... from the calibration program.
Setting reference values
Before starting calibrating make sure that the system has been configured correctly by
setting the right values of gas concentration of: room air (i.e. 20.95% O
2
and 0.03%
CO
2
), of gas mixture contained in the cylinders and the volume of the calibration
syringe (i.e. 3 litres).
Set the reference values using the PC software
This operation must be performed only the first time. The next times, the system keeps
stored the reference values entered in this step.
1. Select Reference Values from the Calibration menu.
2. Type the correct values for the O
2
and CO
2
room air concentration (i.e. 2093 for
20.93%), and do the same for the gas concentration of the calibration cylinder.
3. Type the volume of the calibration syringe (i.e. 3000 for a 3 litres calibration
syringe).
4. Press OK button to confirm changes.