Installation
2800 Laura Lane • Middleton, WI 53562 | 800.288.9383 • fax: 608.836.9044 | www.tcsbasys.com
6
7
2800 Laura Lane • Middleton, WI 53562 | 800.288.9383 • fax: 608.836.9044 | www.tcsbasys.com
6
7
QD2040b at end of the network.
QD2040b in the middle of the net-
work.
1
3
2
Shielded, twisted two-conductor com-
munications wiring with one end earth
grounded. (120 Ω balancing resistors
provided.)
Shielded, twisted two-conductor com-
munications wiring with one end earth
grounded. (120
Ω
balancing resistors
provided.)
4
NOTES:
1.
If using more than 64 controllers,
use the second RS-485 port or
additional QD1010 adapters.
2.
Each controller must use the
same baud rate and be assigned
a unique address.
Two-Wire Network Wiring
Follow this wiring diagram for two-wire (Modbus) wiring systems
(this is not common).
Two-wire diagram
A
B
Shield
A
B
A
B
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
A
B
A
B
Last in Daisy Chain
Shield
Last in Daisy Chain
Earth Ground
Only at one end
120Ω
Terminating
Resistor
A
B
A
B
A
B
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
