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Prelim Draft - Brand Neutral
BACNET IP/MSTP VAV - INSTALLATION INSTRUCTION
NOTE:
NOTE:
NOTE:
The maximum BACnet MS/TP network Bus seg- ment
length is 4,000 ft. (1200 m) using recom- mended wiring.
Repeaters must be used when making runs longer than
4,000 ft. (1200 m). A maximum of three repeaters can be
used between any two devices.
NOTE:
DIP setting of all-ON or all-OFF will enable the Auto MAC
mode in controller and the dip switches will not be used
for MAC addressing.
16
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COMMUNICATION
BACNET MS/TP
Each controller uses a BACnet MS/TP communications port. The
controller’s data is presented to other controllers over a
twisted-pair MS/TP network, which uses the TIA/EIA 485
signaling standard capable of the following baud rates: 9.6, 19.2,
38.4, 76.8, 57.6 or 115.2 Kilobits per second. The BACnet BACnet
controllers are master devices on the MS/TP network. Each
BACnet BACnet controller uses a high-quality TIA/EIA 485
To set the MS/TP MAC address of a BACNET BACnet MSTP
VAV controller:
1.
Find an unused MAC address on the MS/TP net- work to
which the BACnet MS/TP VAV controller con- nects.
2.
Locate the DIP switch bank on the BACNET MS/TP VAV
controller BACnet for addressing.
3.
Powered off the BACNET MS/TP BACnet Controller and
set the DIP switches for the MAC Address you want.
Add the value of DIP switches set to ON to deter- mine
the MAC address. See
below.
transceiver and exerts 1/8 unit load on the MS/TP
network.
The controller features an isolated RS485 interface (terminals
32, 33, and 34) suitable for BACnet MS/TP communication. The
terminal block containing it is Grey. The cable length affects the
baud rate, see
Table 6
below..
Table 6. Baud rate vs. Maximum cable length
Table 7. DIP Switch Values For MS/TP MAC Address
DIP
7
6
5
4
3
2
1
VALUE
64
32
16
8
4
2
1
For example, if only DIP switches 1, 3, 5, and 7 are enabled the
MAC address would be 85 (1 + 4 + 16 + 64 = 85).
1
0 4 0
0
Setting the MS/TP MAC Address
The MS/TP MAC address for each device must be set to a unique
value in the range of 1-127 on an MS/TP network segment
(address 0, 1, 2, & 3 should be avoided as they are commonly
used for the router, diagnostic tools, and as spare addresses). A
seven position DIP switch on the BACnet MS/TP BACnet
controller is used to set the controller's MAC address.
Figure 11. Calculating MAC address
Setting the Device Instance Number
The Device Instance Number must be unique across the entire
BACnet system network because it is used to uniquely identify
the BACnet devices. It may be used to conveniently identify the
BACnet device from other devices during installation. The
BACnet MS/TP BACnet Controllers Device Instance Number is
automatically set when it is added to a WEBStation-NX project.
The Device Instance Number can be changed by the user, which
may be necessary when integrating with a third party or when
attempting to replace an existing controller and it is desired to
maintain the existing Device Instance Number.
All ON
All OFF
IMPORTANT:
This controller is insensitive to bias voltages because of
failsafe chip-set inside and can share the BACnet bus
with other devices with or without bias voltages.
ON
1
2 3 4
5 6 7
ON
1
2 3 4
5 6 7
O
N
1
2
3
4
5
6
7
Baud rate
Maximum cable
length (L)
9.6, 19.2, 38.4, 57.6, 76.8 and
115.2 kbps
4000 ft (1200 m)
64 =
85
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