Communications wiring
Unit Ventilator
CARRIER CORPORATION ©2019
Integration Guide
All rights reserved
3
Protocol Overview
You can set the Unit Vent to communicate 1 of 4 different protocols:
BACnet MS/TP
(page 4)
BACnet ARC156
(page 8)
N2
(page 9)
Modbus
(page 11)
LonWorks
(page 13)
The default setting is BACnet MS/TP. You set the protocol and baud rate on the Comm Selector DIP switches on
the controller. See table below for specific switch settings.
The third party connects to the controller through the Comm port for BACnet MS/TP, N2, Modbus, and through the
Option Card port for the LonWorks Option Card.
NOTES
Changing protocol requires no programming or point assignment by the installer or operator.
Power must be cycled after changing the Comm Selector DIP switches or connecting the LonWorks Option
Card.
Comm Selector DIP switch settings for protocols and baud
Protocol
Baud Rate
3
4
1
2
BACnet MS/TP
(Default)
Off
Off
Select Baud
Select Baud
BACnet ARC156
Off
Off
N/A
N/A
N2
1
On
Off
Off
Off
Modbus
Off
On
Select Baud
Select Baud
LonWorks
2
On
On
On
Off
1
N2
must have 9600 bps baud
2
LonWorks
must have 38.4 kbps baud
Baud Rate
1
2
9,600 bps
Off
Off
19.2 kbps
Off
On
38.4 kbps
On
Off
76.8 kbps
(Default)
On
On
Communications wiring
