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Installation of the Dräger Flame Detector 5000
RS485 Communications
The optional RS485 twisted pair cable is connected to the detector
RS485A +ve signal terminal and the RS485B -ve signal terminal. The
RS485 connection can be used to read the software revision within the
detector. In order to access this information connect the RS485 input of a
RS485 to RS232 to terminals 7 & 14. Connect the RS232 input of a RS485
to RS232 to a PC install DFG software on the PC. The DFG Software can
be used to interogate the Flame 5000 Detector, for any further assistance
contact Dräger Safety UK Ltd.
The software revision will be shown in the get settings box as indicated
adjacent.
Video (twisted pair)
The video twisted pair cable is connected to the detector +Video signal on
terminal 5 and the -Video signal on terminal 6.
Point to Point Connections
In a point to point connection a single detector is connected to the power, RS485 (or mA or Relays) and Video cables.
This arrangement has the best reliability and availability since any single failure in the fi eld equipment or cabling aff ects
only the one detector.
Cable Selection
The installation, local regulations, and standards determine the overall cable specifi cation. This section specifi es
suitable cable characteristics to ensure correct operation of the fl ame detector. There are several diff erent cabling
methods available, each with advantages and disadvantages:
•
Three twisted pair cable, one each for DC power, RS485 and video signals
•
Two twisted pair cable for DC power and mA or Alarm relays, interchangeable with RS485
•
Three twisted pair cable for DC power and mA, or Alarm relays, interchangeable with RS485 and one pair for
video.
•
Three wire, DC power and mA (Current source output).
NOTE: Table below shows absolute maximums for cable lengths; try not to approach these values.
Typical cable lengths (24V Supply)
Installation based on 24V
Number of Flame
nominal supply
Detector and Heater
Detector (no Heater)
NOTE: Increasing the supply voltage to 26V would increase the maximum cable lengths by +30%.
The overall performance and the transmission distance depends on the selected twisted pair cable. Individually
screened twisted pairs off er better electrical immunity.
16
Maximum
Detectors
Power (W)
1.5mm
1
18
1
6
Maximum Cable Length (m) with
Conductors (12 ohms/km)
2
333
1,000
Maximum Cable Length (m) with
2.5mm
Conductors (7.6 ohms/km)
2
506
1,578
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