2800 Laura Lane • Middleton, WI 53562 | 800.288.9383 | www.tcsbasys.com
55
Installation
Three-Wire Network Wiring
Follow this wiring diagram for all three-wire systems
.
NOTES:
In the middle of the network, all network wiring shields should be twisted together and taped off to prevent acci
-
dental grounding. More than one ground on the network wiring can result in communication failure.
A maximum of two terminating resistors can be used.
Three-Wire Diagram
QD3041 at end of the network.
QD3041 in the middle of the
network.
1
3
2
Shielded, twisted three-conductor com-
munications wiring with one end earth
grounded. (120 Ω terminating resistors
provided.)
Shielded, twisted three-conductor com-
munications wiring with one end earth
grounded. (120 Ω terminating resistors
provided.)
4
NOTE:
Each controller must use
the same baud rate and be as-
signed a unique BACnet MS/TP
address and device ID.
A
B
REF
Shield
A
B
REF
A
B
REF
Earth Ground
Only at one end
Drain
Wire
Last in Daisy Chain
120Ω
Terminating
Resistor
COM 1
REF
A
B
Drain
Wire
120Ω
Terminating
Resistor
A
B
REF
A
B
REF
A
B
REF
Last in Daisy Chain
Shield
Last in Daisy Chain
Earth Ground
Only at one end
120Ω
Terminating
Resistor
A
B
REF
A
B
REF
A
B
REF
Shield
Drain
Wire
COM 1
REF
REF
A
A
B
B
120Ω
Terminating
Resistor
1
2
3
3
4
4
4
COM 1
REF
A
B
COM 1
REF
A
B
