16
Instructions for use
|
Dräger PointGard 2000 Series
en
|
Calibration
Ambient conditions and aging cause sensor drifts. Sensor
drifts have a negative impact on the measurement accuracy.
Calibrations restore this accuracy. Depending on the severity
of the drift shorter calibration intervals have to be established.
To evaluate the ambient conditions of a new installations,
shorter calibration intervals with documentation of the drift
should be established. The plant operator should establish
customized calibration intervals with the obtained data.
Under normal conditions, Dräger recommends the following
calibration intervals
1)
:
– Electrochemical sensors (EC): 6-12 months
2)
– Catalytic sensors (CAT): 4 months
– Infrared sensors (IR): 6-24 months
8.1 Test
gases
For test gas properties (e. g. humidity, concentration) refer to
the corresponding sensor data sheet.
Test gas humidity is irrelevant for O
2
sensors.
Depending on the type of calibration different test gases are
used.
Zero gas
Zero gas is a test gas to calibrate the zero point. If ambient air
is free from interfering impurities and measured gas, it can be
used as zero gas. For O
2
sensors, nitrogen (N
2
) is used.
Calibration gas
Calibration gas is a test gas to calibrate the sensor sensitivity
during span calibration. Calibration gas is a known
concentration of the measured gas diluted with clean air or
nitrogen. For O
2
sensors no calibration gas is needed, as
oxygen from ambient air is used.
8.2 Preparation
of
Calibration
WARNING
Health hazard due to test gas
Inhaling test gas may risk health or lead to death.
►
Do not inhale test gas.
►
Observe risks and security statements related to the test
gas (Refer to data sheets and instructions figuring on
calibration devices).
CAUTION
Triggering alerts by test gas
Applied test gas may trigger alerts.
►
Make sure that test gas is no longer applied after
calibration.
Prerequisites:
– Sensor has finished the warm-up phase
(6 Commissioning of the instrument).
– Date and Time are set (11.2 Setting date and time).
8.2.1 Preparing calibration set-up
For all transmitters except PointGard 27x0 IR:
Refer to the following figure.
Calibration equipment:
– Dräger pressure regulator (1), for reactive gases use
stainless steel pressure regulator
– Dräger calibration adapter (2) (part number 6810536).
– Tubing (3)
– Dräger calibration gas cylinder (4)
Prepare calibration
1. Attach the pressure regulator to the calibration gas
cylinder.
2. Fit calibration adapter to the sensor.
3. Connect the tubing to the barbed fitting.
4. Enter the menu, see 7.6.3 Entering the menu
For PointGard 27x0 IR:
Refer to the following figure.
Calibration equipment:
– Dräger pressure regulator (1), for reactive gases use
stainless steel pressure regulator
– Dräger calibration adapter (5) (part number 6811610).
– Tubing (3)
– Dräger calibration gas cylinder (4)
Prepare calibration:
1. Attach the pressure regulator to the calibration gas
cylinder.
2. Fit calibration adapter to splash guard until it snaps into
place.
This does not apply for duct mount applications or if the
process adapter number is used (see installation
instructions for PIR 7x00 accessories).
3. Make sure that the sealing surfaces around the openings
of the splash guard are clean. The insect guard does not
have to be removed.
4. Connect the tubing to the barbed fitting.
5. Enter the menu, see 7.6.3 Entering the menu
1) Observe sensor data sheet and sensor IfU
2) For applications in line with EN45544-1 the calibration interval must
not exceed 6 months.
