Rockwell Automation 20-COMM-B BACnet MS/TP Adapter - Manual (Page 31)

Configuring the Adapter 3-3
While there are many ways to implement Device Instance and network
strategies, the example shown in
Figure 3.1 illustrates one logical
approach.
In this example, two individual Floor Level Networks are connected to
the Building Level Network through a router which allows devices on
each network to share the same MAC address. However, each device on
the network must have a unique Device Instance which, in this case,
consists of 4 digits. The first digit (in bold) represents the Building or
Floor number. The last 3 digits represent the device’s set MAC address.
Figure 3.1 Building Automation Network Example
Setting the Device Instance Number
Router
Bldg 1/Flr 1
MAC Address 1
Device Instance 1001
MAC Address 50
Device Instance 1050
MAC Address 2
Device Instance 1002
MAC Address 127
Device Instance 1127
Building
Controller 1
Floor Level Network 1 (BACnet MS/TP)
Building Level Network 1
Other Brand
Building Automation
Product
Other Brand
Building Automation
Product
Bldg 2/Flr 2
MAC Address 1
Device Instance 2001
MAC Address 50
Device Instance 2050
MAC Address 2
Device Instance 2002
MAC Address 127
Device Instance 2127
Floor Level Network 2 (BACnet MS/TP)
Other Brand
Building Automation
Product
Other Brand
Building Automation
Product
Building
Controller 2
Building Level Network 2