Operation
PrimaX
22
GB
The lower explosive limits [LEL] of the gases and vapours in the following example
were taken from EN 60079-20-1. Local regulations may specify different LEL val-
ues; always ensure the correct values are used.
It is recommended that the PrimaX zero is calibrated using clean air, free of meas-
uring gas, and calibration gas of approximately 50 % of measuring range [comb.
and TOX] in air of the gas being monitored. The recommended calibration gas for
oxygen is 50% of measuring range, but for a measuring range 0-25 vol% O
2
, the
device can be calibrated using 20.9 vol% O
2
.
Calibration example for Methanol
Calibration Procedure
The calibration can be performed as a manual or an automatic calibration [ M-04].
Automatic Calibration [automatic]: a countdown is displayed. After the count-
down the value is measured and displayed. When the value is stable the current
value is selected automatically.
Manual Calibration [manual]: the measuring value is displayed. When the value
is stable press ENTER to select the current value.
It is recommended that all calibration components are connected before
starting a calibration as it is necessary to apply test gas to the device
during a countdown.
When monitoring flammable gas in safety related applications the
PrimaX must be calibrated with a known concentration of the gas being
monitored.
For oxygen a zero calibration with gas is not required, it is performed in-
ternally.
Methanol calibration gas concentration being used = 3,5 Vol%
Methanol volume concentration for 100%LEL = 6,0 Vol%
Methanol calibration gas concentration in %LEL
3,5 Vol% CH
4
O x
100% LEL
= 58,3 % LEL
6,0 Vol% CH
4
O
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