Communications wiring
RTU Open v3
Carrier Proprietary and Confidential
CARRIER CORPORATION ©2016
Integration Guide
All rights reserved
8
The following example shows the DIP switches set for 76.8k (Carrier default), and MS/TP.
6
Connect the MS/TP network to the controller's
J19
port. Connect to
Net+
,
Net-
, and
SHLD
.
Wire specifications
○
A dedicated 22 AWG shielded twisted pair wire (EIA 485)
○
Maximum wire length 2000 feet (610 meters) or 32 nodes
○
Devices should be daisy-chained and not star-wired
○
Attach the drain/shield wire to both ends of the network segment and through every controller
NOTE
Use the same polarity throughout the network segment.
7
Turn
on
the RTU Open's power.
Troubleshooting BACnet MS/TP
Check the following to troubleshoot your RTU Open:
1
Verify that the BAS and controller are both set to speak the BACnet MS/TP protocol on the Comm Selector
DIP switches
DS3 - DS6
.
2
Verify that the BAS and the controller are both set for the same baud rate:
○
Baud rate DIP switches DS2 and DS1
○
Obtain a Modstat of the controller. Scroll to the bottom of the page to
Network Communications
to view
the active protocol and baud rate.
3
Verify that the BAS is configured to speak 2-wire EIA-485 to the controller. The BAS may have to configure
jumper or DIP switches on their end.
4
Verify that the BAS and the controller have the same communication settings (8 data bits, No Parity, and 1
stop bit).
5
Verify proper connection wiring between the BAS and the controller.
6
Verify that the controller has a unique MAC address on the MS/TP bus. The controller’s MS/TP MAC address
is set by its rotary address switches.