Communications wiring
RTU Open v3
Carrier Proprietary and Confidential
CARRIER CORPORATION ©2016
Integration Guide
All rights reserved
7
BACnet MS/TP
To set up the RTU Open for BACnet MS/TP
Refer to
Appendix B
(page 46) for the Protocol Implementation Conformance Statement, or download the latest
from
BACnet International
http://www.bacnetinternational.net/catalog/index.php?m=28
.
NOTE
This controller counts as a full load on the MS/TP bus.
1
Turn
off
the RTU Open's power.
NOTE
Changes made to the switches when the controller is on will not take effect until the power is cycled!
2
Using the rotary switches
MSB
(
SW1
) and
LSB
(
SW2
), set a unique MS/TP MAC address for the RTU Open.
Set the
MSB
(
SW1
) switch to the tens digit of the address, and set the
LSB
(
SW2
) switch to the ones digit.
Valid addresses are 01-99.
NOTE
The rotary switches also determine the BACnet device instance of the controller on the BACnet
network. The BACnet device instance is automatically generated based on the scheme 16101xx, where “16”
is the BACnet vendor ID for Carrier Corporation, and xx equals the rotary switch address.
EXAMPLE
To set the controller’s MS/TP MAC address to 01, point the arrow on the
MSB
(
SW1
) switch to 0
and the arrow on the
LSB
(
SW2
) switch to 1. Internally, the BACnet device instance is automatically
generated as 1610101.
3
Set the
SW3
Comm Selector DIP switches
DS1
and
DS2
for the appropriate communications speed (9600,
19.2k, 38.4k, or 76.8k bps).
NOTE
Use the same baud rate and communication settings for all controllers on the network segment. The
RTU Open is fixed at 8 data bits, No Parity, and 1 Stop bit for this protocol's communications.
Baud Selection Table
Baud Rate
SW3/DS2
SW3/DS1
9,600
Off
Off
19,200
On
Off
38,400
Off
On
76,800
On
On
4
Set
SW3
Comm Selector DIP switches
DS3
through
DS6
for BACnet MS/TP. See table and example below.
5
Leave
DS7
and
DS8
in the OFF position. These switches are not applicable to MS/TP.
SW3 Protocol Switch Settings for MS/TP
DS8
DS7
DS6
DS5
DS4
DS3
Off
Off
Off
Off
On
Off