Performing A Bump Test - Dräger Polytron 8900 UGLD Notice D'utilisation

To verify the sensor is providing correct measurement data,
the sensor should undergo a regular bump test utilizing the
calibration kit.
In general calibration is not necessary. To check whether a
calibration is necessary, first perform a bump test.
7.1 Test gas
The acoustic sound pressure emitted by a leak varies by the
type of target gas, the leak size and the distance to the
device.
Test gas for ultrasonic sensors is compressed air or nitrogen.
The calibration adapter generates the ultrasonic sound
pressure at defined flow rate.
Thus, the calibration adapter generates the needed ultrasonic
signal to calibrate the system span.
7.2

Performing a bump test

Once installed, the instrument typically does not need regular
calibrations. Nevertheless, the calibration can be checked and
performed if a deviation outside the acceptable tolerance is
detected.
A bump test checks alarm activation and sensor sensitivity
without setting off the alarms.
Prerequisites:
– Background noise is < 50 %.
– Environmental temperatures within 0 °C to 40 °C (+32 °F
to +104 °F).
Calibration equipment:
– Dräger Polytron 8900 UGLD Calibration Kit (8328042)
To perform a bump test:
1. Place the calibration adapter onto the sensor up to the
stop.
2. Enter the menu, see 6.6.3 Entering the menu.
3. Select Settings > Instrument > Bump test and confirm.
 The maintenance symbol is displayed
 The analog output is set to the maintenance signal.
4. Open calibration gas cylinder valve.
 After a short period of stabilization time (~ 10 s), the
displayed value should stabilize at the percentage of
measurement range that is indicated on the calibration
adapter.
 If the value deviates by > 6 %, perform a span
calibration.
5. Press OK to return to measurement.
The calibration adapter must not be soiled. Store the
calibration adapter in a clean environment. Dräger
recommends storing the calibration adapter in the calibration
kit case.
Instructions for use |
Dräger Polytron
®
8900 UGLD
7.3 Preparing a calibration
A calibration needs to be performed in a controlled
environment with the following prerequisites:
– Background noise is < 55 dB.
– Environmental temperatures within +15 °C to +35 °C
(+59 °F to +95 °F).
Calibration equipment:
– Dräger Polytron 8900 UGLD Calibration Kit (83 28 042)
To prepare a calibration:
1. Remove the sensor from the instrument or the remote
sensing head.
2. Take the sensor to a controlled environment.
3. In the controlled environment insert the sensor into a
Polytron 8900 UGLD instrument.
4. Calibrate the sensor by using the calibration kit.
● Performing a zero calibration, see 7.4 Performing a
zero calibration.
● Performing a span calibration, see 7.5 Performing a
span calibration.
5. Re-insert the sensor in it's previous location.
6. Re-integrate the instrument into the alarming system.
7.4 Performing a zero calibration
NOTICE
Zero calibrations may cause malfunctions
Zero calibrations should not be necessary.
Zero calibrations set the zero point of the measurement
range.
The zero point of the measurement is 0 % and should only be
calibrated under laboratory conditions.
► Do not calibrate the zero point at the installation site with
background noise present.
If a zero calibration is still necessary, the ultrasonic sensor
can be detached and calibrated with a separate Polytron 8900
UGLD instrument under laboratory conditions.
Calibration can be aborted at any time. To abort calibration
select back.
Prerequisites:
– Calibration is prepared.
To perform a zero calibration:
1. Attach silencer cap to the sensor up to the stop.
2. Enter the menu, see 6.6.3 Entering the menu.
3. 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.
4. Ignore the message Apply zero gas, select Next and
confirm.
 The current value is displayed.
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Calibration en
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