Dräger Flame 5000, Technical Manual

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16
Installation of the Dräger Flame Detector 5000
RS485 Communications
The optional RS485 twisted pair cable is connected to the detector
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 deVideo 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 a ff ects
only the one detector.
Cable Selection
The installation, local regulations, and standards determine the overall cable speci fi cation. This section speci fi es
suitable cable characteristics to ensure correct operation of the fl ame detector. There are several di ff 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
nominal supply
Number of Flame
Detectors
Maximum
Power (W)
Maximum Cable Length (m) with
1.5mm 2 Conductors (12 ohms/km)
Maximum Cable Length (m) with
2.5mm 2 Conductors (7.6 ohms/km)
Detector and Heater 1 18 333 506
Detector (no Heater) 1 6 1,000 1,578
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 o
ff er better electrical immunity.