Power Supply; Detector Wiring Terminals - Dräger Flame 5000 Technical Manual

then care should be taken to ensure the cable armour braid provides a suitable earth or that the enclosure earth stud
(external) is separately connected to a suitable earth point using a single core 4mm
All detector cable screens should be connected to the local clean earth at the control panel. The screens (and twisted
pairs) should be maintained to within 1" (25.4mm) of the terminations at the detector, within all junction boxes and at
the control panel. Where unscreened cables are used for panel wiring, then all cables must be suitably twisted into
pairs and video cables should be segregated from other signal sources.

Power Supply

The detector requires an absolute minimum supply voltage of 18V, as measured at the detector terminals. The system
power supply voltage and power distribution should be arranged such that on the longest cable run the detector(s)
has a supply voltage of greater than 18V. All detectors must share a common 0V supply. In distributed systems with
multiple DC-DC power supply units all 0V supplies must be connected together. Where this is not possible the RS485
and Video signals may need to be galvanically isolated, such as with a fi bre optic transceiver.
To prevent RS485 communications or video corruption the maximum voltage drop on the 0V return must not exceed
+4V or -1V. Voltages greater than these will exceed the common mode input range of the RS485 and Video drivers.
Power supply cable selection is described in section: Detector Power Supply Cabling

Detector Wiring Terminals

The wiring terminals and confi guration links are mounted in the rear section of the enclosure and are accessible by
removal of the rear cover from the enclosure. The electronics and the fi eld terminals are separated so that there is no
reason to remove the electronics in order to access the fi eld terminals. This is to prevent damage to the electronics
when the unit is being connected to the fi eld cable.
The device is supplied in one of two options:
1. As a unit that provides relay contacts for the alarm and fault circuits across which alarm and end of line resistors
are fi tted. When the unit is disconnected from the fi re panel, the output from terminals A and B switch to the
RS485 protocol; this allows a Dräger Engineer access to the detectors confi guration from the local equipment
room.
2. As a unit that provides 4-20mA output. When the unit is disconnected from the fi re panel, the output from terminals
A and B switch to the RS485 protocol; again this allows a Dräger Engineer access to the detectors confi guration
from the local equipment room.
This may then be used to access the software revision within the detector via the 'get settings' menu as described in
the 'RS485 Communications' section.
The alarm relay and the 4-20mA output is factory selectable for latching and non-latching operation. If the latching
mode is selected then if an alarm is generated the detector will remain in alarm until the power supply to the unit
is interrupted. If the non-latching operation is selected then the detector will remain in alarm for a minimum of 15
seconds, the fi re panel to which the detector is connected must be capable of latching the alarm and there is no need
to interrupt the power supply to the detector to reset the alarm. Local authority having jurisdiction approval is required
for connection to FM Approved fi re alarm control units.
Installation of the Dräger Flame Detector 5000
earth cable.
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