Overview about BACnet properties
BACnet objects are composed using properties which are either specified in the BACnet standard or may be proprietary. Some properties are required, where others may be optional. A few properties are required to be writable, others may be made writable if needed. The conformance code in the PICS document describes which properties belong to which group:
R = required
O = optional
W = writable
The column "CC" describes the requirements by the BACnet standard.
"WA" describes the write access options in TwinCAT.
The following table shows an example object (analog input, not all properties are shown) from the PICS document (the document can be downloaded here: www.beckhoff.com/bacnet).
Analog Input
Property | Data Type | CC | WA |
|---|---|---|---|
Object_Identifier | BACnetObjectIdentifier | R | R |
Object_Name | CharacterString | R | W |
Object_Type | BACnetObjectType | R | R |
Present_Value | REAL | R | R |
Description | CharacterString | O | W |
Device_Type | CharacterString | O | W |
Status_Flags | BACnetStatusFlags | R | R |
Event_State | BACnetEventState | R | R |
Reliability | BACnetReliability | O | R |