Dräger Pulsar 7000 Serie Notice D'utilisation page 42

en Description
3.2 Feature description
The Dräger Pulsar 7000 Series includes various gas warning systems. The system is available in the following variants:
Dräger Pulsar 7000 Series – Open Path Gas Detector

Dräger Pulsar 7000 Series – Duct-Mount Gas Detector

Combustible hydrocarbons absorb a certain wavelength range of the infrared radiation. The gas warning systems use this
property.
Each gas warning system consists of a transmitter and a receiver. The transmitter generates infrared light using multiple Xenon
light sources and radiates it in pulses. Optical sensors in the receiver detect whether or not a gas cloud containing hydrocarbons
in the measuring path between the transmitter and receiver is absorbing part of the infrared radiation. The intensity of the infrared
radiation arising at the receiver is converted into analogue current signals. These signals are transmitted by the receiver via a
4 to 20 mA interface to a control unit (e.g. Dräger REGARD
zero-point capture range. Minor signal fluctuations or signal noise within this range is set to exactly 4 mA.
The gas warning system measures an integral gas concentration in the measuring path. The signal that the receiver sends to the
control unit is proportional to the measured integral gas concentration. The receivers are factory-calibrated to different gases,
depending on the gas warning system used:
Methane/Propane: Pulsar 7700 RX

Ethylene: Pulsar 7900 RX

Influences from rain, snow or contamination on the lenses are almost completely compensated for via the measurement of a
reference wavelength of the infrared radiation.
The optics of the transmitter and receiver are equipped with a heating to optimize performance in the event of ice, snow or
condensation.
A DIGITAL LINK connection can be installed for communication between transmitter and receiver. Via the DIGITAL LINK
connection, the receiver can increase the signal strength and flash frequency in the transmitter (strong mode). This means that
adverse environmental influences can be compensated for to a certain degree. Without a DIGITAL LINK connection, no
communication is carried out between the transmitter and receiver. This means that system has the following limitations:
No strong mode

Longer response times (see Chapter 8 on Page 62)

Slower measured value refresh rate

Limited operation in alignment mode

Dräger recommends using the DIGITAL LINK connection.
Transmitter and receiver are configured for different ranges.
The components can be combined as follows, depending on the required measuring distance:
Transmitter
Pulsar 7000 TX S (4 - 60 m)
Pulsar 7000 TX L (30 - 200 m)
Pulsar 7000 TX S (4 - 60 m)
Pulsar 7000 TX L (30 - 200 m)
Pulsar 7000 TX S (4 - 60 m)
Pulsar 7000 TX L (30 - 200 m)
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7000). The 4 to 20 mA interface is equipped with a configurable
Pulsar 7700 RX S (4 - 120 m, methane, propane)
without DIGITAL LINK connection
4 - 60 m
30 - 120 m
Pulsar 7700 RX L (100 - 200 m, methane, propane)
-
100 - 120 m
Pulsar 7900 RX S (4 - 120 m, ethylene)
4 - 30 m
30 - 60 m
Receiver
with DIGITAL LINK connection
4 - 60 m
30 - 120 m
-
100 - 200 m
4 - 60 m
30 - 120 m