Calibrating Transmitter; Zero Point Adjustment - Dräger PEX 3000 Gebrauchsanweisung

Calibrating transmitter

Calibrating transmitter
For this chapter:
— Mentioning Type XTR 0000 also includes type XTR 0001 as well as the
transmitters type XTR 0090 or XTR 0091 with remote sensing head SE Ex PR
... DD or HT M DD (100 %LEL).
— Mentioning Type XTR 0010 also includes type XTR 0011 as well as the
transmitters type XTR 0090 or XTR 0091 with remote sensing heads SE Ex LC
... DD (10 %LEL).

Zero point adjustment

To enter the calibration menu press the key ▼for more than one second but less
than 3 seconds. The display shows a flashing point on the right bottom indicating
the calibration mode.
 Navigate by means of keys ▲ or ▼ until the display shows ZE ("ZEro") and enter
the menu by pressing the keys (▲+▼). The output signal is set to 3.4 mA to
signal the calibration procedure mode to the controller unit.
 Apply zero gas to the sensor –
without calibration adapter:
Ensure that the transmitter is in clean ambient surroundings (no flammable
gases or vapours present),
or
with calibration adapter:
Supply clean air at a flow rate of approx. 0.5 L/min via the calibration adapter.
— The transmitter's display shows the currently measured gas concentration which
in general is slightly different from zero. Negative values down to "–9" % LEL or
"–.9" (type XTR 0010) are displayed.
 Wait until the reading has stabilised (max. 3 minutes) and press keys (▲+▼). By
this the current sensor signal is converted into an up-dated zero point also shown
on the display (ideally "0").
 Press keys (▲+▼) to save the up-dated zero point and to terminate the zero
adjustment function.
After a sensor replacement the zero point might be misaligned so much that the
display shows "--". In this case press keys (▲+▼) to save preliminary zero and
again follow the above zero adjustment procedure.
 Press keys (▲+▼) to exit this function. The display shows ZE again.
 Press key ▲ to switch back to the measurement mode or press key ▼ to perform
the sensitivity adjustment.
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NOTICE