Distech ECYPSE - Page 129

BACnet MS/TP Communication Data Bus Fundamentals
ECLYPSE User Guide 129
Inter-Building BACnet Connection
BACnet network connections between buildings must be made using BACnet/IP as shown
below.
Building #2
- Alarm
- Trend Log
- Schedule
EC-Net
AX
Supervisor
- Data Bus Management
- Data Bus Integration
- Device Configuration and
programming
- Graphical Interface
Configuration
EC-Net
AX
Pro Web Browser
- User Interface
- Remote Access
- Embedded EC-Net
AX
Pro
MAC: 3
DI: 20 003
MAC: 4
DI: 20 004
MAC: 5
DI: 20 005
MAC: 6
DI: 20 006
MS/TP
Network # 11
IP Network # 4
MAC: 3
DI: 10 003
MAC: 4
DI: 10 004
MAC: 5
DI: 10 005
MAC: 6
DI: 10 006
IP Network # 1
MS/TP
Network # 10
MAC: 3
DI: 30 003
MAC: 4
DI: 30 004
MAC: 5
DI: 23 005
MAC: 6
DI: 30 006
IP Network # 3
MS/TP
Network # 20
Building #1
BBMD
KEY:
DI: Device Instance
EOL: End of Line
MAC: Media Access Control
IP Network # 3
DI: 30 000
EC-BOS MAC on
Network # 30 = 0
EOL Internally Set EOL Internally Set EOL Internally Set
EOL
ON
EOL
ON
EOL
ON
ECY Series
BACnet/IP
DI: 20 000
EC-BOS MAC on
Network # 20 = 0
DI: 10 000
EC-BOS MAC on
Network # 10 = 0
ECY Series ECY Series
EOL
ON
EOL
ON
EOL Internally
Set
EOL Internally
Set
IP
Router
IP Network # 2
EOL
ON
EOL Internally
Set
Figure 11-17: Typical Inter-Building Connection Using BACnet/IP or FOX
BACnet/IP Broadcast Management Device Service
Though BACnet/IP uses IP protocol to communicate, a standard IP router does not forward
broadcast messages which are important in BACnet to identify services that are available
within the BACnet internetwork.
When two ECY Series Controllers communicate to each other over a standard IP connection
that is separated by an IP router, both ECY Series Controllers need the BACnet/IP
Broadcast Management Device (BBMD) service to be configured and operational.
The BBMD service identifies BACnet messages on the BACnet MS/TP network that are
intended for a device located on another BACnet network. The BBMD service encapsulates
these messages into an IP message to the appropriate BBMD service of the other BACnet
MS/TP network(s). The BBMD service on these networks strips out the encapsulation and
sends the BACnet message on to the appropriate devices.
When sending BACnet messages across a standard IP connection that has an IP router,
there must be one BBMD service running on each BACnet MS/TP network.