Calibration
|
en
Instructions for use
|
Dräger PointGard 2000 Series
17
8.3 Gas flow for calibrations
Gas flow varies depending on the sensor.
Gas flow should correspond to the environmental conditions
during operation (e. g. duct measurement with higher flows
than 2 l/min)
8.4 Zero
calibration
Ambient air can be used to zero the sensor instead of
Nitrogen or Synthetic Air only if the area is known to be free of
the target gas or any gas to which the sensor may be cross-
sensitive (as listed on the sensor data sheet). In this case, no
cylinder or calibration adapter is needed for the zero
calibration.
WARNING
Calibration fault at zero calibration
Insufficient ambient air flow may cause calibration errors.
►
Make sure that the ambient air flow to the sensor is
sufficient.
PointGard 2100 EC-specific:
For Oxygen (O
2
) sensors a zero calibration does not change
any value in the firmware or sensor. Thus, the zero calibration
function can be used to check the correct zero reading when
Nitrogen is applied to the sensor. The PointGard 2100 EC will
indicate a fault state if a zero check fails with a deviation of
more than 0.6 Vol% O
2
from zero. In case of a fault, repeat
the zero check or change the sensor if necessary. Use
Nitrogen (N
2
) for verification.
PointGard 2200 CAT-specific:
Sensors must not be calibrated with pure nitrogen. Catalytic
sensors need oxygen to work properly.
PointGard 27x0 IR-specific:
For PointGard 2720 IR (with PIR 7200 to detect carbon
dioxide), only Nitrogen or Synthetic Air without any CO
2
content may be used for a zero calibration.
8.4.1 Performing zero calibration
Calibration can be aborted at any time. To abort calibration
select
back
.
Prerequisites:
– Sensor has finished the warm-up phase
– Calibration is prepared.
Perform zero calibration
1. Select
Calibration
>
Zero calibration
and confirm.
The Maintenance signal is transmitted by the analog
interface, no alarm or fault relays are switched and the
symbol is
displayed.
The message
Apply zero gas
is displayed.
2. Apply synthetic air or nitrogen, if ambient air cannot be
used.
a. Set gas flow corresponding to the sensor used (see
"Gas flow for calibrations", page 17)
3. Select
Next
and confirm.
The current value is displayed.
After the test gas has been applied to the sensor for 3
minutes and the displayed value is stable perform
calibration.
4. Select
calibrate
and confirm.
The message
please wait...
is displayed.
The new current value is displayed.
5. Select
Next
and confirm.
6. Turn off gas flow and remove the calibration adapter from
the sensor or disconnect tubing.
If the current value is not within the alarm range:
7. Select
Next
and confirm.
The instrument returns to the calibration menu.
8.5 Span
calibration
PointGard 2200 CAT / 2200 CAT Remote IR / 2700 IR -
specific:
The span calibration has to be performed within 24 h after the
last valid zero calibration.
PointGard 2200 CAT Remote with IR sensor:
Due to the design of the DSIR gas sensor, the output signal of
the gas sensor is limited to 45 % . . . 55 % of the instrument-
internal supply voltage. If the gas concentrations increase
further after the maximum sensor output signal has been
reached, this does not lead to an increase of the values
displayed on the instrument response transmitted to the
35153
EC sensor
0.5 l/min ± 10%
All other sensors
0.5 l/min - 2 l/min
7
PIR 7x00
EC
DSIR
CAT Ex
1
3
4
3
2
2
5
