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Maintenance
6.3.2
Checking the alignment of the gas warning system
If there is no DIGITAL LINK connection, the transmitter must be set to alignment mode separately. Prior to zero calibration,
the alignment mode must be exited separately at the transmitter.
1. Check that the gas warning system is correctly aligned.
a. Connect the Pulsar Interface Adapter to the receiver communication connector and switch on the communication mode.
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b. Connect the HART
c. Establish the communication on the HART
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d. On the HART
handheld terminal, select 5 / Maintenance in the main menu.
e. In the 5 / Maintenance menu, select 1 Start alignment.
Next to 3 Alignment Mode, Active must be displayed.
The maintenance signal is transmitted on the 4 to 20 mA interface.
The green LEDs flash on both transmitter and receiver.
f. In the 5 / Maintenance menu, select 4 Graphical alignment.
Select 1 Alignment graph.
g. Check if the measuring points of both transmitter and receiver remain within the range of 30 scale divisions from 0 on the
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HART
handheld terminal.
2. If the measuring points are not within the desired range, align the gas warning system (see section 4.2.6 on page 16, step 6.).
3. Perform a zero calibration (see section 4.2.6 on page 16, step 8.).
6.3.3
Calibrating the 4 to 20 mA interface
NOTICE
For the duration of the maintenance work, deactivate the alarm function in the control unit if necessary. During the maintenance
work, the gas warning system issues current values of 4 mA to 20 mA.
Dräger recommends a zero calibration before the 4 to 20 mA interface is calibrated. On the HART
the gas measured value and the output current are displayed under 2 / Measurement values. If the digital display of the
gas measured value is 0.0 LEL-m and the 4-20 mA signal in the control unit deviates from 4.00 mA, Dräger recommends
calibrating the 4 to 20 mA interface.
The current ranges in which the 4 to 20 mA interface can be adjusted are significantly smaller than ±0.5 mA by 4.00 mA or
20.00 mA. A current signal that is too low or too high can indicate a small gas concentration or that the zero-point is no
longer correct.
A suitable ammeter must be used for calibration. This must be integrated as closely as possible to the control unit so that
the current of the 4 to 20 mA interface can be measured with sufficient accuracy.
1. Connect the Pulsar Interface Adapter to the communication connector and switch on the communication mode.
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2. Connect the HART
handheld terminal to the Pulsar Interface Adapter.
3. Establish the communication on the HART
4. In the 6 / Analog config menu, select 8 4-20 mA calibration.
The LEDs on the receiver indicate the status "Calibration of the 4-20 mA interface".
5. Follow the instructions on the HART
Enter the value from the ammeter for "4.00 mA output".
Enter the value from the ammeter for "20.00 mA output".
6. Repeat step 5 if necessary.
7. Exit the 8 4-20 mA calibration function
The gas warning system changes to measuring mode.
The LEDs indicate "Measuring mode".
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8. Exit the HART
application.
1) The gas warning system exits the 4-20 mA calibration mode automatically after 1 hour and returns to measuring mode.
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handheld terminal to the Pulsar Interface Adapter.
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handheld terminal via the Device Description.
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handheld terminal via the Device Description.
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handheld terminal:
1)
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handheld terminal,
