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Topics in this section cover integrating BACnet™ Thermostat controllers
into a building automation network. These are advanced topics for
control technicians and engineers. The
BACnet
Thermostat can function
as a stand-alone controller or it can be connected to a
BACnet
MS/TP
network. The topics in this section are reference material for control
technicians or engineers that will be installing and setting up a
BACnet
Thermostat that is connected to a network.
Connecting to a Network
Before connecting the
BACnet
Thermostat to a
BACnet
MS/TP
network, configure the network properties. See the topic Set Up
Communications on page 15 for the procedure to set the following.
• Device Instance
•
MAC address
•
Baud
Use the following principles when wiring the
BACnet
Thermostat to an
MS/TP network:
• Connect no more than 128 addressable
BACnet
devices to one
MS/TP network.
•
Use 18 gauge, twisted pair, shielded cable for all network wiring.
•
Connect the (–A) terminal in parallel with all other (–) terminals.
•
Connect the (+B) terminal in parallel with all other (+) terminals.
•
Connect the shield to an earth ground at only one location on
the network.
The controllers or devices on the physical ends of the MS/TP wiring
segment must have end-of-line (EOL) termination installed for proper
network operation. Set the end-of-line termination to ‘On’ using
the EOL switches. A 120Ω resistor across the positive and negative
communication wires will also work as an EOL termination.
Figure 12: BACnet MS/TP Network Wiring
Figure 13: Location of EOL switch
Application Drawings