Communications wiring
RTU Open v5
CARRIER CORPORATION ©2019
Integration Guide
All rights reserved
6
4
Set the remaining DIP switches as follows:
BACnet MS/TP DIP switch settings
8
7
6
5
4
3
Off
Off
Off
Off
On
Off
The following example shows the DIP switches set for 76.8k (Carrier default), and BACnet MS/TP.
5
Connect the BACnet MS/TP network to the controller's
J19 Network Comm
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.
6
Turn
on
the RTU Open's power.
Adjusting BACnet MS/TP properties using an Equipment Touch
You may need to adjust the following BACnet MS/TP protocol timing settings using the Equipment Touch.
Max Masters
- defines the highest MS/TP Master MAC address on the MS/TP network.
For example, if there are 3 master nodes on an MS/TP network, and their MAC addresses are 1, 8, and 16, then
Max Masters would be set to 16 (since this is the highest MS/TP MAC address on the network).
This property optimizes MS/TP network communications by preventing token passes and “poll for master”
requests to non-existent Master nodes.
