BACnet PTP Serial Driver Manual
Page 16 of 34
Appendix A. Useful Features
Appendix A.1. BACnet Object Names
When an external BACnet Client builds a list of Object Names, the BACnet Server Map Descriptor names
determine the BACnet Object Name. If the Map Descriptor length is greater than 1, the Object Name will
be suffixed with the index into the Map Descriptor. For example, if the Map Descriptor name is
SMD_AI_01 and the length 3, then the Object Names will be SMD_AI_01[0], SMD_AI_01[1] and
SMD_AI_01[2].
Appendix A.2. Network Number
If multiple BACnet Nodes are specified on the Server side, the FieldServer automatically defaults to
virtual operation. In effect, the FieldServer simulates a software router. BACnet identifies this FieldServer
using a combination of its network number and IP/MAC address. The default Network number of a
FieldServer is 5. If there is more than one FieldServer on a BACnet intranet with multiple nodes, the
default network number of the additional FieldServers will need to be changed and a unique number
allocated to each.
A unique network number will need to be assigned if
both
of the following conditions are true:
•
The FieldServer has multiple BACnet Server nodes.
•
There is more than one FieldServer on a network which includes multiple BACnet nodes.
To override the FieldServer’s default network number 5 include the following in the configuration file:
Section Title
Bridge
Column Title
Function
Legal Values
Title
FieldServer name.
Text
Network_Number*
Specify a unique network number if there are multiple virtual
Server nodes.
1-65534,
5
Example
// FieldServer Driver specific parameters
Bridge
Title
, Network_Number
BACnet Server
, 6
NOTE: While it is theoretically possible to have up to 65535 virtual nodes, it is recommended that
a maximum of 32 is configured. If an application requires the configuration of more than
32 virtual nodes, consult Sierra Monitor technical support.
