What the Structured View Object Is
The Structured View object, defined in Clause 12.29 of ANSI/ASHRAE 135-2024, is a container that organizes other objects into a hierarchy. It holds references to subordinate objects, and those subordinates can themselves be Structured Views, so a BACnet device can present its point database as a tree a workstation navigates instead of a flat list. The Structured View carries no process data of its own; it is purely organizational.
Subordinate_List names the child objects, Node_Type classifies what this node represents (an area, a system, a piece of equipment), and the optional annotation and relationship arrays describe how the children relate to the node. Represents optionally points at a separate object that concretely stands for the same real-world entity the view models. The Structured View supports no intrinsic reporting and applies no event algorithm.
Where You’ll See It
- Navigation trees. A controller exposes a building-area-system-equipment hierarchy of Structured Views so an operator drills down to a point instead of scrolling a flat object list.
- Equipment grouping. A rooftop unit’s inputs, outputs, and setpoints gathered under one Structured View node that names the unit.
- Self-describing devices. A device publishes its own logical organization, letting discovery tools present it the way its designer intended.
Required Properties
Clause 12.29 requires every Structured View object to provide these properties. Datatypes are the spec’s names: CharacterString is text, and the BACnet-prefixed types are structured values defined by the standard. BACnetNodeType names the kind of node, and Subordinate_List is the array of references to the child objects.
| Property | Datatype | What it holds |
|---|---|---|
Object_Identifier | BACnetObjectIdentifier | The object’s type and instance number, unique within the device |
Object_Name | CharacterString | The human-readable node name, unique within the device |
Object_Type | BACnetObjectType | Always structured-view for this object |
Node_Type | BACnetNodeType | What this node represents (system, area, equipment, and similar) |
Subordinate_List | BACnetARRAY[N] of BACnetDeviceObjectReference | The references to the child objects under this node |
Property_List | BACnetARRAY[N] of BACnetPropertyIdentifier | The list of properties this instance actually implements |
Optional Properties
The properties integrators meet most are Subordinate_Annotations (labels shown against each child in the tree), Node_Subtype (a finer classification beyond Node_Type), and Represents (the concrete object this node stands for).
| Property | Datatype | Group |
|---|---|---|
Description | CharacterString | General |
Node_Subtype | CharacterString | General |
Subordinate_Annotations | BACnetARRAY[N] of CharacterString | Group members |
Subordinate_Tags | BACnetARRAY[N] of BACnetNameValueCollection | Group members |
Subordinate_Node_Types | BACnetARRAY[N] of BACnetNodeType | Group members |
Subordinate_Relationships | BACnetARRAY[N] of BACnetRelationship | Group members |
Default_Subordinate_Relationship | BACnetRelationship | Group members |
Represents | BACnetDeviceObjectReference | General |
Tags | BACnetARRAY[N] of BACnetNameValue | Tagging and profile |
Profile_Location | CharacterString | Tagging and profile |
Profile_Name | CharacterString | Tagging and profile |
Related Objects
- Group: collects several objects’ values for one read, where the Structured View organizes them for navigation.
- Global Group: the cross-device value collector, another way of grouping points.
- Device: the object whose full point database a Structured View helps navigate.
What Chipkin Provides
The Structured View object is a first-class object type in the CAS BACnet Stack, modeled with its subordinate hierarchy. Talk to us about modeling your device’s points.