Connecting To A Network - Daikin BACnet Series Installation Manual

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.
IO-DAPPS
Figure 12: BACnet MS/TP Network Wiring
Figure 13: Location of EOL switch
www.daikinac.com
Application Drawings
29