Installing the RTU Open
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
12
Wiring for communications
The RTU Open communicates using BACnet on the following types of network segments:
• MS/TP communicating at 9600 bps, 19.2 kbps, 38.4 kbps, or 76.8 kbps
• ARC156 communicating at 156 kbps
For more networking details, see the Open Controller Network Wiring Installation Guide.
Wiring specifications for BACnet MS/TP and ARC156
Cable: 22 AWG or 24 AWG, low-capacitance, twisted, stranded, shielded copper wire
Maximum length: 2000 feet (610 meters)
Do not apply line voltage (mains voltage) to the controller's ports and terminals.
To wire the controller to the BACnet network
1 Pull the terminal connectors from the RTU Open's power terminals.
2 Check the communications wiring for shorts and grounds.
3 Connect the communications wiring to the Network Comm J19 port's screw terminals labeled
,
,
and
.
Use the same polarity throughout the network segment.
4 Set the communication type and baud rate.
Set DIP switches 1 and 2 to...
MS/TP The appropriate baud rate. See the
diagram
on the controller.
On
ARC156 N/A. Baud rate will be 156 kbps regardless of the DIP
switch settings.
Off
Use the same baud rate for all controllers on the network segment.
5 Wire the controllers on a BACnet MS/TP or BACnet ARC156 network segment in a daisy-chain configuration.
6 If the RTU Open is at either end of a network segment, connect a BT485 to the RTU Open.
7 Insert the power screw terminal connector into the RTU Open's power terminals.
8 Verify communication with the network by viewing a Module Status report in the i-Vu® interface.