Preparing The Test Gas Supply - Dräger X-node Technisches Handbuch

Zero gas
The zero gas is a test gas which is used to calibrate the zero value. If
the ambient air is free from unwanted contaminations and measured
gases, it can be used as a zero gas.
For O sensors, nitrogen (N
2 2
only a zero point check is possible. Here, the display must show
< 0.6 Vol% after 3 minutes.
Calibration gas
The calibration gas is a test gas used to calibrate sensor sensitivity
during a span calibration. The calibration gas is a known
concentration of the measured gas, diluted with fresh air or nitrogen.
For O sensors, no calibration gas is required as oxygen from the
2
ambient air is used.
6.2

Preparing the test gas supply

The test gas must be fed unpressurised with a flow rate of 0.5 L/min.
Prerequisites
– Warm-up phase of the sensor has been completed.
– Time and date are set (see "Setting the time and date", page 65).
Work equipment
– Test gas cylinder with pressure reducer, for aggressive gases with
stainless steel pressure reducer
– Calibration adapter with hose nozzles (order no. 68 10 536)
– Hose, type depends on gas properties (e.g. FKM hose, order no.
12 07 068)
Technical manual |
Dräger X-node
) is used as zero gas. For O sensors,
2
DANGER
Health risk from test gas
Inhalation of test gas is a risk to health and can even cause death.
► Do not inhale test gas.
► Take note of the dangers associated with test gas as well as the
hazard warnings and safety advice (see, for example, safety data
sheets, instructions on the test equipment).
WARNING
Triggering of alarms by test gas
The continued supply of test gas can trigger alarms.
► Make sure that the supply of test gas has been terminated.
1. Connect the calibration adapter (Fig. 1/2) and test gas cylinder
(Fig. 1/1) with the hose.
2. To discharge the test gas, connect a hose to the second port of
the calibration adapter.
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Calibration
69