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1
BACNET PTP DESCRIPTION
The BACnet PTP driver allows the FieldServer to transfer data to and from devices using the BACnet
protocol over a serial RS-232 physical layer. The FieldServer can emulate either a Server or Client.
All information in a BACnet system is represented in terms of objects. The Object_Identifier is a 32-bit
code that identifies the type of Object (also identified by the Object_Type Property) and its "Instance"
number, which together uniquely identify the Object within its BACnet device. Theoretically, a BACnet
device could have over four million Objects of a particular type. The Object_Name is a text string, which
has a unique capability. BACnet devices may broadcast queries for devices that contain Objects with a
specific Object_Name. This can greatly simplify project setup.
BACnet requires one Device Object to be present in every BACnet device. The Device Object makes
information about the device and its capabilities available to other devices on the networks. Before one
BACnet device starts control-related communications with another, it needs to obtain some of the
information presented by the other device's Device Object. Unlike other Objects, the Device Object's
Instance number must be unique across the entire BACnet internetwork because it is used to uniquely
identify the BACnet devices. It may be used to conveniently identify the BACnet device from other
devices during installation.
Standard object types are used to hold real time data and other information. Each Object Type is
referenced by a number, for example 0 represents an Analog Input.
Each Object consists of a number of prescribed properties, the main property being the Present_Value.
Objects are monitored and controlled through their properties. The Analog Input Object is representative
of the Objects involved directly with control elements and many of its Properties reflect this.
The information that follows describes how to expand upon the factory defaults provided in the
configuration files included with the FieldServer.
2
DRIVER SCOPE OF SUPPLY
2.1
Supplied by Sierra Monitor Corporation
Part #
Description
Connector adapter – DB9M to DCE, RTS/CTS, DSR/DTR
FS-8917-03
2.2
Provided by supplier of 3
Part #
Description
BACnet Controller
rd
party equipment
Page 5 of 34
BACnet PTP Serial Driver Manual
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