31-XXXX-XX
22
Prelim Draft - Brand Neutral
BACnet IP/MSTP VAV Controller - INSTALLATION
INSTRUCTION
NOTE:
NOTE:
NOTE:
Automatic MAC addressing will be enabled only if dip
switches are all-on or all-off.
COMMISSIONING
Automatic MAC Addressing
In contrast to other controllers, the BACNET MSTP
controllers features automatic MAC addressing.
The MAC addresses which the individual BACNET MSTP VAV
controller in the BACnet MS/TP channel assign to themselves
are not assigned in sequential order.
Rather, they assign the MAC Address in the range of min MAC to
max MAC (these are exposed as the proprietary properties id
1028 (min MAC) and 1029 (maxMAC) under device object)
currently not in use by another device in the BACnet MS/TP
channel (the MAC Address of “0” is reserved by default for the
router / plant controller, itself).
All BACNET MSTP VAV controllers are BACnet MS/TP masters.
Every master performs periodic polling for the possible
appearance of new masters. Each master “knows” the identity
of the “next” master (i.e., that BACNET MSTP VAV controller
with the next-highest MAC Address) on the BACnet MS/TP bus
and to which it must therefore pass the token. The polling
process includes a search for new masters which might have
MAC addresses lying between its own MAC address and that of
the “next” master.
The property maxMaster specifies the highest- allowable
address for master nodes. The maxMaster is set to 127/64/35 by
default, thus guaranteeing that, on a BACnet MS/TP bus with, for
example, 35 BACnet MSTP VAV controllers, all of the other
BACnet MSTP VAV controllers will be found. Following properties
are writeable and can be changed:
•
maxMaster
•
min MAC
•
max MAC
•
MAC address.
Figure 21. Automatic MAC addressing
In the scenario depicted in
Figure. 21
above, some of the
controllers in the BACnet MS/TP channel do not feature
automatic MAC addressing; rather, their MAC addresses were
assigned manually. Thus, when a new BACNET MSTP VAV is
added to the channel, and its automatic MAC addressing
function is triggered, it will assign itself an available (unused)
MAC address within the range of min MAC and max MAC
values.
Operator interface LEDs
The controller features the following LEDs:
Table 12. Status LED
NOTE:
You should not attempt to program a MAC Address
outside the range of min MAC and max MAC (1 to 127).
Legend
Colour
Function
TX1
Green*
The IP VAV controller is equipped
with two Tx LEDs and two
corresponding Rx
LEDs.
These LEDs indicate the
transmission and reception of
data by the two RS485
interfaces
RX1
RX1
RX2
Green
Indicates that the Bluetooth is
working properly
Green
Breathe
Indicates that the device is
working properly.
Yellow
Blink
indicates that the device is
having minor issues such as
connection failure.
Red
Blink
Indicates that the device is
having severe issue such as CPU
failure.
*In case of no communication LED will not glow.
