VAV T4 RT VAV Zone Controller
BACnet Communication Module User Guide
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Introduction
The VAV T4 RT VAV Zone Controller BACnet
®
Communication Module User Guide provides information about using
the controllers in the zoning system with BACnet communications feature. The BACnet communication protocol for
building automation and control networks enables communication between client devices within a network. The
controller provides a BACnet network interface between BACnet client devices and DEOS Controller series devices. It
uses the BACnet Master Slave/Token Passing (MS/TP) protocol at the BACnet MAC layer.
Pre-requisites
The BACnet communication user guide assumes that you are familiar with the concepts of BACnet and its
terminology.
Advantages of BACnet
BACnet enabled controllers have the following advantages:
Quick Message Transmission.
The controller uses a synchronous implementation for BACnet messages
making it quick and efficient. Each BACnet confirmed service request is answered as quickly as possible
without using the
Reply Postponed
frame. The MS/TP implementation is performed within
Tusage_delay
of
15 minutes to ensure a
Tusage_timeout
value within 20 minutes.
MS/TP Support.
The controller supports a Full Master Node state machine for MS/TP. The Max_Master and
the instances are configured to the device object through
BACnet WriteProperty
service or via the device's
Programming Mode. The MAC address and the MS/TP baud rate setting of 9600, 19200, 38400, and 76800
are also set through the
BACnet Write Property
service or via the device's Programming Mode. In
Programming
mode, the device is configured through the device’s keypad. For more information about the
WriteProperty, refer to
Table 3 - Object Types Supported
.
BIBB Support
. The controller functions the same way as the B-ASC type profile server and supports the
specific BIBB as per their relevant definitions.
o
DS-RP-B
o
DS-RPM-B
o
DS-WP-B
o
DS-WPM-B
o
DM-DCC-B
o
DM-DDB-B
o
DM-DOB-B
o
DM-RD-B
o
DM-TS-B
o
DM-UTC-B
o
DS-COV-B
o
DS-COVP-B
o
SCHED-WS-I-B
Object Support
. The controller supports a fixed list of BACnet visible values, which appear as Present_Values
of various BACnet standard object types in addition to a device object. For more information, refer to
Table 3 -
Object Types Supported
.
Alarms
. The controller supports indication of various alarm conditions through value changes in properties of
several objects. However, it does not generate BACnet event notifications.
