Dräger X-am 3500 Mode D'emploi page 43

5.5 Calibrate the gas detector
WARNING
Incorrect measured values!
An incorrect calibration may prevent alarms from
triggering, or alarms may trigger late.
► Do not close the outlet of the calibration adapter /
exhaust gas hose.
► Always carry out the fresh air / zero adjustment
before the span calibration.
NOTICE
Damage to the sensors!
When using the exhaust gas hose, the sensors may be
damaged in the case of direct suction on the exhaust
gas hose.
► If necessary, lead the exhaust gas hose (max. length
2 m) to an exhaust of outside.
If measurement gas or calibration gas is changed,
the affected channel must be calibrated.
Observe the following notices for the calibration:
● For the fresh air calibration of Dräger IR sensors for
explosive hydrocarbon, it is assumed that the
change in the zero-point leads to a change of less
than or equal to ±5 %LEL of the measured value at
50 %LEL. If the deviation is greater than ±5 %LEL,
the span calibration is invalid.
● For the zero-point calibration of Dräger IR sensors, it
is assumed that the change in the zero-point leads
to a change of less than or equal to ±5 %LEL or
0.05 Vol% CO of the measured value at 50 %LEL
2
or 0.5 Vol% CO . If the deviation is greater than
2
±5 %LEL or 0.05 Vol% CO
invalid and an error or a warning is displayed
(configurable).
● For a span calibration of Dräger IR sensors, it is
assumed that a valid zero-point calibration exists (no
more than 30 min. old), otherwise an
acknowledgeable warning is displayed.
Adjustment may not be possible due to instrument and
channel errors.
5.5.1 Carrying out a fresh air calibration
To improve accuracy, a fresh air calibration must be
carried out in the event of a zero deviation.
X-am
, the span calibration is
2
®
3500
Observe the following notices for the calibration:
● For the fresh air calibration of Dräger IR sensors for
explosive hydrocarbon, it is assumed that the
change in the zero-point leads to a change of less
than or equal to ±5 %LEL of the measured value at
50 %LEL. If the deviation is greater than ±5 %LEL,
the span calibration is invalid.
● For the fresh air calibration, the display is set to
20.9 Vol% for the XXS O
Requirements:
– Fresh air calibration can only be carried out if at
least once sensor supports the fresh air calibration.
– The fresh air must be free of measurement or
interfering gasses.
– The gas detector is switched on and warm-up
phases 1 and 2 are complete.
To carry out a fresh air calibration:
1. Switch on the gas detector.
2. Open the fresh air calibration (depending on the
configuration):
If the fresh air calibration was released for user level
0 by the Dräger CC-Vision PC software:
● Select > Maintenance > Fresh air cal..
If the fresh air calibration was not released for user
level 0 by the Dräger CC-Vision PC software:
a. > Log in
b. Enter and confirm the password.
c. Select Maintenance > Fresh air cal..
3. Select to start the fresh air calibration.
 All measuring channels which are included in the
fresh air calibration flash, and all others are
greyed out.
The result is displayed as follows for every
measuring channel:
fresh air calibration successful.
fresh air calibration failed.
4. If necessary, press
control. In this case, a calibration happens
immediately.
Dräger recommends using the automatic stability
control (wait until the gas detector has automatically
carried out the calibration).
 The new measured value is displayed for
confirmation.
The result is displayed as follows:
fresh air calibration successful.
fresh air calibration failed.
Maintenance
.
2
to overrule the stability
en