Network Wiring Details - Trane BACnet MS/TP Installation, Operation And Maintenance Manual

Network Wiring Details

BACnet
Follow these steps to connect communication wiring as shown in
1. Review the wiring diagram and determine which BACnet
2. Attach the communication wire between two adjacent devices on the link and verify that polarity of the
3. At each unit controller, join the shield wires together and insulate the connection with electrical tape
4. Repeat steps 2 and 3 for each unit controller on the link.
Note: For more information about the specific unit controller you are wiring, see the installation guide for
Important:
Figure 6.
+
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Tracer BACnet
Note: The Tracer
Observe the maximum link length recommendation
The maximum length of a 18 AWG network wire is 4,000 feet. The maximum lenght of a 22 AWG network
wire is 2,000 feet. Wire runs longer than recommended may experience communication issues.
Note: There is no support for repeaters on BACnet
Use a Tracer
Because the amount of communication signal degradation increases as the length of communication wire
increases toward the maximum of 4,000 ft. (1,219 m), Trane requires that a Tracer
(TBT) module (PN: X13651524-01) be connected at each end point of the network. For correct termination
placement, follow these guidelines:
•
•
BAS-SVX51L-EN
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wiring must use a daisy-chain configuration.
Note: It is not necessary to place the Tracer
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However, a Tracer
wires is maintained.
to prevent accidental shorting of the wire.
the specific controller.
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Tracer unit controllers are not grounded on the DIN rail. It is necessary to ground each
controller to a good earth ground.
Daisy-chain configuration for BACnet
terminator
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UC800 cannot power a BACnet
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BACnet terminator at each end of the link.
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All BACnet MS/TP links must be properly terminated. Use a Tracer
of the link.
Connect the communication wire shield to the ground terminal of the link termination block at the Tracer
SC+ as shown in Figure 7. The Tracer
only place on the link that the shield wire should be grounded.
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SC+ at the end of the of the communication link.
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BACnet Terminator must be wired at each end of the link.
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wiring
Twist wire and
tape shields
Unit Controllers
(Power Side)
(Each UC should be
grounded to a good earth
ground.)
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terminator.
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MS/TP links.
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SC+ provides the ground for the BACnet
Best Practices
Figure 6.
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MS/TP link is being wired.
Tape back
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Tracer BACnet
terminator
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BACnet
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BACnet terminator at each end
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MS/TP link. This is the
+
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Terminator
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