Vaisala GMK220 - Manual (Page 7)

Chapter 2______________________________________________________________Product description
VAISALA _____________________________________________________________________________5
Additional equipment
The following additional equipment is needed for checking and
calibration operations:
•
Traceable reference gas/es as follows:
spot checking: one gas with CO
2
concentration within the
measuring range of the probe. Accuracy shall be 1% (or better).
two-point calibration: two gases with CO
2
concentrations
representing the low and high end of the probe's measuring range.
See the requirements below.
•
Pressure regulator (giving about 1 bar pressure)
•
PC and a terminal software (e.g. Windows ®
Hyper Terminal)
•
Power supply, 24 VDC/1A
In addition, values on the ambient temperature (with accuracy of ± 0,5
ºC) and barometric pressure (with accuracy of ± 1 hPa) are needed as
input data during the checking or calibration procedure.
Requirements for the calibration gases
Low end
calibration gas N
2
gas with a purity of N50 (or better).
Traceable to appropriate standards (for
example NIST).
High end
calibration gas Mixture of CO
2
and N
2
gases
.
CO
2
concentration shall be 95...105 % of the
measuring range of the probe. Accuracy shall
be 1 % (or better). Traceable to appropriate
standards (for example NIST).