Dräger PEX 3000 Manual Del Usuario página 33

4.4.6 AZ – Switch on automatic zero-point correction
The transmitter has automatic zero-point correction (Autozero) from software
version 2.4. This can partially correct zero-point deviations owing to long-term
drift of the sensor and to environmental influences depending on the time of day
and improve the quality of the measured values.
The correction rate and the absolute limit of the automatic zero-point correction
are based on the tolerances of EN/IEC 60079-29-1.
The automatic zero-point correction is not part of the metrological suitability
test in accordance with EN 60079-29-1 and is deactivated at the factory. Dräger
recommends activating the automatic zero-point correction.
1. Navigate using the ▲ or ▼ keys until the display shows AZ ("AutoZero")
and confirm by pressing the (▲+▼) keys.
– The display shows "on" or "of" depending on the current setting.
2. Use the ▲ or ▼ key to turn the Autozero on or off.
3. Press the keys (▲+▼) to save the setting and exit the function. The display
shows AZ once again.
4. Press the ▲ key five three times to return to measuring mode.
5 Operation
Although the transmitter was factory-tested before delivery, the
commissioning after installation must include the zero-point and sensitivity
adjustment. The commissioning process must be concluded with a functional
test of the complete gas detection system.
|
5.1 Installing the transmitter
NOTICE
The PEX 3000 transmitter is an EMC class A item of equipment. The transmitter
may cause radio interference in the domestic area; in this case, the operator
may be requested to implement appropriate measures.
5.1.1 Mounting
PEX 3000 type XTR 000x use position: The gas inlet area of the sensor should
preferably point downwards.
PEX 3000 type XTR 001x use position: The gas inlet area of the sensor must
point downwards.
If it is ceiling-mounted, a mounting bracket must be used.
– Mount the transmitter in vertical position at a location with little vibration and
maximum temperature stability (no direct sunlight) in the vicinity of a
possible leak.
– Consider the full scope of environmental conditions to which the transmitter
is exposed. Prevent external influences such as splash water, oil, corrosive
aerosols (salt mist), etc., and the possibility of mechanical damage.
– Leave at least 30 cm free space beneath the transmitter to provide
accessibility for calibration work.
NOTICE
Certain substances in the atmosphere to be monitored may impair the
sensitivity of the sensor (DrägerSensor PR M DQ or LC M) installed in the
transmitter.
The following substances are known at present:
1. Catalyst poisons in high concentrations or for prolonged exposure times, for
example sulphur and phosphorus compounds, silicon compounds, metal-
organic vapours
2. Corrosive substances such as ammonia and halogenated hydrocarbons
(releasing halogens such as bromine, chlorine or fluorine upon catalytic
oxidation),
| en
Operation
33