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5
CONNECTIONS
All controls connected to the network will need to be programmed with the same communication baud rate as well as a
unique communication address from 0 to 255, excluding 248. On controllers with displays, this can either be done from
the face of the controller using the keypad and display, or using TCS Insight software. TCS Technical Support can access
the QD2040c online and change the address of a controller.
Use 22 AWG, twisted shielded 3-conductor cable for network wiring. Network wiring should start at one controller and
go to the next and then go to the next, and so on until the final controller is reached. Wiring is such that all “A” wires are
connected to “A” wires, all “B” wires are connected to “B” wires, and all “REF” wires are connected to “REF” wires.
A bus resistor (120 Ohm) is to be placed at the end of the bus network between the “A” and “B” wires. The bus resistor
(120 Ohm) may be placed at the QD2040c, between the “A” and “B” wires if the controller is at the end of the network.
If the QD2040c will be in the middle of the network, do not wire in the terminating resistor on the QD2040c terminal
block (See 2 below). Finally, connect one end (ideally the furthest end from the QD2040c) of the shield wire of the
network wiring to earth ground. TCS recommends a 250 milliseconds time out period for all wired networks, and 1000
milliseconds for wireless networks. If you encounter timeout errors please contact tech support.
NOTE:
In the middle of the network, all network wiring shields should be twisted together and taped off to prevent
accidental grounding. More than one ground on the network wiring can result in communication failure.
NOTE:
A maximum of 2 terminating resistors can be used. See Figure below.
RS485 Controller Network Wiring and Setup