Echelon IzoT BACnet Developes - Manual (Page 16)

Device ID and Device Name
The Object ID of the BACnet Device Object (“Device ID”) is required to be unique
“Internetwork Wide”, as is the Object Name of the Device Object (“Device Name”).
As a default, the BACnet Stack synthesizes the ObjectID and Object Name from the
Neuron ID, guaranteeing uniqueness, but for most projects, you should rename and
renumber your devices. This can be achieved by writing a new Device ID and a new
Device name to the system using the BACnet Browser for IzoT or any other standard
BACnet workstation that supports this functionality. These values get stored in
persistent memory and allow failed devices to be replaced without having to reconfigure
the BACnet Clients.
Mapping Table Structure
Not all fields of a SNVT are of interest to all users, so a method of specifying what gets
mapped has been established. The Mapping Table is hard-coded by the programmer in
the file BAClon/mapping.nc. This has been implemented and takes the form of C code
Macro statements, that allow the programmer to specify the NV name of interest, and
the BACnet Mapping desired. An example is shown below.
mapAnaToSNVT_lux ( "Illuminance", localLight),
And for SNVTs with multiple fields..
mapAnaToSNVT_switch__value ( "nvoSwitchOut.value - AI", nvoSwitchOut),
Requirements to add the BACnet Stack to a FT 6050
application
Create a new project as per normal NodeBuilder procedures. When the project has been
set up, copy the BAClon subdirectory from one of the sample projects across to the new
project directory.
Modify the project ‘main’ or ‘OEM source file’, similar to what is shown in the source code
of the sample projects. A few particular #includes and source code modifications have to
be made to an existing project.
1. #includes
a. #include "baclon.h"
Required for BACnet
2. Source file changes
a. In the OEM source file, the following statements are required
#include "BAClon\sys\ blonsys.nc "
when (msg_arrives) { if ( handle_BACnet () ) { return; } }
when (reset) { init_BACnet( ); }
16 Using BACnet