Orion System BACnet Link - Manual (Page 6)

Technical Guide
BACnet ® Link Interface 6
BACnet ® Link Overview
The BACnet ® Link provides the communications interface between the
Orion system and a BACnet ® network. One BACnet ® Link can support
up to sixteen controllers. The BACnet ® Link connects to the BACnet ®
network using Master-Slave/Token Passing (MS/TP) LAN data link
protocol.
The BACnet ® Link supports 3 different controller types (device ob-
jects). These are the Orion MUA II, VAV/CAV and the CW/HW con-
trollers.
BACnet ® Link Device Object
The information that follows describes the characteristics of the BACnet ®
Link Device Object. The properties for the BACnet ® Link Device Ob-
ject are listed in Table 2.
Object Name
The Object Name is a 15 byte character string that can be set through
the BACnet
® front end.
Instance Number
The Instance Number of the Device Object is determined by the ad-
dress jumper setting on the BACnet
® Link. The BACnet ® Link has two
address jumpers which allows the addressing number range to be from
0 to 3. The Instance Number of the Device Object would be the jumper
number plus 600192. This means there can be only four BACnet
® Links
(Device Objects) on the entire local BACnet ® system installation.
Location and Description
The Location and Description are 15 bytes character strings that can
be set through BACnet
® .
Local Time and Date
The BACnet ® Link (Device Object) does not have a hardware real time
clock. It does however keep a software timer running once the time and
date has been set through the BACnet
® front end (by others). Since this
is a software timer, if the BACnet ® Link loses power, the time will be
lost or incorrect and will need to be reset.
WattBacObjectTypes
The BACnet ® Link (Device Object) amends the following object type
to BACnet ® ’s object type, BACnetObjectType.
WattBacObjectTypes := Enumerated {
CwHw (259)
MuaII (258)
VavCav (257)
}
If any of these WattBacObjectTypes conflict with other custom BACnet ®
object types on your BACnet ® system, please contact WattMaster con-
trols.
Programming- General Information
Local Address (MAC address)
The BACnet ® Link’s Local Address (MAC address) on the MS/TP
LAN is determined by the address jumper on the device. The Local
Address is always the address jumper plus 32. Therefore, the
BacnetOrionInterface device’s Local Address (MAC address) can be
set to address 32, 33, 34 or 35. See Figure 3 for address switch setting
information.
BACnet ® Services Supported
The BACnet ® Link supports the following BACnet ® services:
ReadProperty Service ReadPropertyMultiple Service
WriteProperty Service Who-Has and I-Have Service
Who-Is and I-Am Service
MS/TP LAN Baud Rate
The OE367-22 BACnet ® Link (Device Object) is able to detect the Baud
rate of the host BACnet ® MS/TP LAN and automatically adjust its Baud
rate to match the host. The BACnet ® Link will then operate at the host’s
Baud rate of 9600, 19200, 38400 or 76800 Baud as required.
Table 2: BACnet ® Link Device Object Properties
BACnet® Link Device Object Properties
Property Identifier Property Data Type
Read
or
Write
APDU_Timeout Unsigned R/O
Application_Software_Version CharacterSting R/O
Data_Base_Revision Unsigned R/O
Description CharacterSting R/W
Firmware_Revision CharacterSting R/O
Local_Date Date R/W
Local_Time Time R/W
Location CharacterSting R/W
Max_APDU_Length_Accepted Unsigned R/O
Max_Master Unsigned R/O
Max-Info_Frames Unsigned R/O
Model_Name CharacterSting R/O
Number_Of_APDU_Retried Unsigned R/O
Object_Identifier BACnetObjectIdentifier R/O
Object_List BACnetARRAY[N] R/O
Object_Name CharacterString R/W
Object_Type BACnetObjectType R/O
Protocol_Conformance_Class Unsigned(1..6) R/O
Protocol_Object_Types_Supported BACnetObjectTypesSupported R/O
Protocol_Services_Supported BACnetServicesSupported R/O
Protocol_Version Unsigned R/O
Segmentation_Supported BACnetSegmentation R/O
System_Status BACnetDeviceStatus R/O
Vendor_Identifier Unsigned16 R/O
Vendor_Name CharacterString R/O