Echelon IzoT BACnet Developes - Manual (Page 12)

BACnet Interface Overview
The following figure depicts the BACnet interface.
FT 6000 Based LonWorks Device
Lon Application
( User Code)
Lon Network
Variables
BACnet Stack
LonTalk Stack
Static (Flash/
EEPROM)
Dynamic
(RAM)
BACnet to
Lon
Mapping
Function
BACnet to Lon
Mapping
Configuration and
Support
Mapping Table
Protocol Layer – IzoT
LonTalk
Reads and
Writes
BACnet
Reads and
Writes
Figure 3. Functional Overview
In this figure, the items shown in blue are the normal Neuron Chip functions and data
structures, and the ones in green are the new BACnet related functions and data
structures.
At the bottom of the diagram, arrows represent both IzoT and BACnet read and write
messages. These can be transferred over FT10, and are not exclusive, so normal
L
ON
W
ORKS
operation can occur at the same time as BACnet activity.
BACnet messages are identified by LonTalk Message Codes, and are routed through the
BACnet Stack where they are interpreted, and BACnet-only operations may access the
Mapping Table and respond to the BACnet Client without any further impact to the
LonTalk side of the system.
12 Using BACnet