Detcon 6400-N4X - Manual (Page 36)

1600/6400-N4X
1600/6400-N4X- Instruction Manual Rev. 1.1 Page 32 of 38
Device Hook-Up
Installation should begin by deciding where devices will be located and how the connections between devices
and the master will be established. The ideal scenario would look like Figure 36. The example shows the 880
Controller connected to 11 slave devices using a daisy-chain wiring scheme. This would require 2 different
twisted pair cables, one pair for power and the other for the RS-485 data bus.
Connections would be point-to-point starting at the master and running to the last slave. The RS-485 data
cable should come into the sensor enclosure and be connected to the A & B terminals. The next segment of
cable should also connect to the A & B terminals and leave the enclosure headed for the next device. The
shields must be tied together inside the enclosure and not allowed to short to any other wires or surfaces. The
shield should be connected only inside the 1600/6400 enclosure to the shield terminal. The Rt label in the
drawing shows where the termination resistors would be installed.
Figure 36 Daisy Chain wiring diagram
Daisy Chain Wiring is ideal, although wiring may already exist or the wiring cannot be run this way for some
reason. Figure 37 below shows a more realistic wiring situation that may occur.
Figure 37 Unbalanced Data Bus
In this case it is impossible to balance the data bus because there is no distinct beginning or end to the cable
run. The best way to make this type of installation successful is to install repeaters in a few key areas as
01 02 03
05
06 07
09
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04
0a 0b
Control Room
09
08
0a
Control Room
01 02
07 06
0b
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03
Rt
Rt