Owner's manual

GMM20W CO
2
module
Sensor Systems Division U300en-1.1
1999-11-16
SERVICE AND MAINTENANCE
The GMM20W module has an excellent
stability and requires almost no mainte-
nance. A full after sales calibration and
service facility is naturally provided by
Vaisala and its distributors.
In case the user prefers to do the calibra-
tion himself, calibration gases and
equipment are also available. Vaisala's
portable CO
2
meters together with the
Calibration Kit provide for easy and
convenient on-site calibration checks
(see the corresponding manuals for
detailed instructions).
GMM20W should be adjusted if the
reading differs too much from the
reference value during checking (note
that in any case, only slight differences
are expected). For this purpose, we
recommend Vaisala’s Software Kit
19222GM which includes a floppy disk
and a serial COM adapter.
Connect the cable to the connector
marked “Serial Com” on the main PCB
of the module and to the connector A on
the serial COM adapter (see Figure 3).
In order to achieve full accuracy, the
module has to be calibrated against
accurate and traceable calibration gases
in stable environmental conditions
(temperature, pressure). Accurate cali-
brations are usually performed in labora-
tories; in these calibrations, temperature
and pressure corrections have to be
made. For further details, consult your
local Vaisala representative.
Figure 3 Connection of the serial communication cable