Figure 16 daisy chain wiring diagram, Figure 17 unbalanced data bus, Device hook-up – Detcon 1640-N4X User Manual

Page 28: Figure 18 daisy chain wiring diagram, Figure 19 unbalanced data bus

1640-N4X

1640-N4X Instruction Manual

Rev. 0.0

Page 24 of 28

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 18. The example shows the
1640 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 Model 1640 cabinets to the shield terminal. The Rt label in the
drawing shows where the termination resistors would be installed.

Figure 18 Daisy Chain wiring diagram

Control Room

Daisy Chain Wiring is ideal, although wiring may already exist or the wiring cannot be run this way for some
reason. Figure 19 shows a more realistic wiring situation that may occur.

Figure 19 Unbalanced Data Bus

Control Room