Installing The Transmitter; Mounting; Mounting The Transmitter; Installing Electrical Connections - Dräger PEX 3000 Mode D'emploi

4.1

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.
4.1.1

Mounting

Operating position: The transmitter must be mounted such that the sensor's gas
inlet area is pointing 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 splashing 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. Polymerising substances such as acrylo nitrile, butadiene and styrene,
2. Corrosive substances such as ammonia and halogenated hydrocarbons
(releasing halogens such as bromine, chlorine or fluorine when oxidised),
3. Catalyst poisons such as sulphur and phosphorous compounds, silicon
compounds and metal-organic vapours.
Dräger PEX 3000
The sensors used are based on measuring elements (pellistors), which are
poison-resistant (PR) and thus have a longer life span than conventional
sensors if catalyst poisons occur. However, there is still the rule to shorten the
test or calibration intervals if catalyst poisons are expected to occur in the
atmosphere to be monitored.
Pay attention to the ventilation conditions!
– Always arrange the sensing head and transmitter in the air flow between a
possible leak or collection point and possible source of ignition.
Note the density of the gas!
– For gases with densities lower than that of air, such as hydrogen, methane
or ammonia, the transmitter must be located above a possible leak or at the
highest points where greater concentrations of gas may be found.
– For gases and vapours with densities greater than that of air, the transmitter
must be installed beneath a possible leak or at the lowest points where
these gases and vapours may be present.
4.1.2

Mounting the transmitter

– The transmitter is secured with screws (diameter: 4 mm) inserted through
the housing (see "Drilling templates", page 47).
4.2

Installing electrical connections

CAUTION
Electrical wiring is only to be laid and connected by an expert in compliance with
the pertinent regulations and laws concerning electrical equipment in potentially
explosive atmospheres as well as the approval conditions.
Connection between the transmitter and controller
– The maximum cable lengths for loads of 250 Ohms can be found in the
following table.
Operation