Structured View
A Structured View object groups other objects into a hierarchy, such as a building, its floors and the equipment on each floor. It holds references to its members, which can be in this device or another one, and can reference other Structured View objects. Clients use it to browse a device by structure instead of a flat list.
Typical uses
Section titled “Typical uses”- Site, building, floor and room tree
- Group all objects of one air handler
- Browse equipment by system
- Label members with notes for operators
- Show the same objects under more than one parent
Key properties
Section titled “Key properties”| Property | What it holds |
|---|---|
| Node_Type | What this node stands for in the tree, such as a building, a floor, a system or a room. |
| Node_Subtype | Optional text that refines the node type. |
| Subordinate_List | The objects that sit under this node. |
| Subordinate_Annotations | Optional text for each member, in the same order as the list. |
| Represents | Optional reference to the object that this node describes as a whole. |
How it behaves
Section titled “How it behaves”The object is a container. It is not commandable, and the standard defines no COV or event algorithm for it. A client reads Subordinate_List and then reads each member itself.
With the CAS BACnet Stack
Section titled “With the CAS BACnet Stack”Enable it with the STACK_OPTION_OBJECT_TYPE_STRUCTURED_VIEW build option. CASBACnetStackDLL.h has no function dedicated to this type, so create it with BACnetStack_AddObject. The stack serves the object identifier, object type, property list and status flags itself; your callbacks serve every other property. A member list that lives in your own storage is read through a callback registered with BACnetStack_RegisterCallbackGetPropertyObjectIdentifier.
Related object types
Section titled “Related object types”Properties
Section titled “Properties”The properties ASHRAE 135-2024 clause 12.29 defines for this object type.
How to read the table:
- Conformance is what the standard asks of every object of this type: R is required, W is required and writable by a client, O is optional. A digit after the letter marks a condition in the standard that decides when the property is present or writable, such as support for intrinsic reporting.
- Present by default: yes means the stack presents the property as soon as you add the object; no means it
is optional and you turn it on with
BACnetStack_SetPropertyEnabled. This is the stack’s starting setup, so it can differ from the conformance code. - Writable is whether a client can write the property by default. Change it with
BACnetStack_SetPropertyWritable. - not in profile means the stack does not offer this property for this object type.
- Value when your callback does not answer: “Held by the stack” means the stack stores and serves the value itself and does not ask your callbacks. Otherwise it is the value the stack answers when your callback declines or is not registered.
| Property | Datatype | Conformance | Present by default | Writable | Value when your callback does not answer |
|---|---|---|---|---|---|
| Object_Identifier | BACnetObjectIdentifier | R | yes | no | Held by the stack. |
| Object_Name | CharacterString | R | yes | no | "Object <type>,<instance>", such as "Object 0,1" for Analog Input 1. |
| Object_Type | BACnetObjectType | R | yes | no | Held by the stack. |
| Description | CharacterString | O | no | no | "" |
| Node_Type | BACnetNodeType | R | yes | no | 0 |
| Node_Subtype | CharacterString | O | no | no | "" |
| Subordinate_List | BACnetARRAY[N] of BACnetDeviceObjectReference | R | yes | no | No default: the read fails. |
| Subordinate_Annotations | BACnetARRAY[N] of CharacterString | O | no | no | "" |
| Property_List | BACnetARRAY[N] of BACnetPropertyIdentifier | R | yes | no | Held by the stack. |
| Subordinate_Tags | BACnetARRAY[N] of BACnetNameValueCollection | O | no | no | No default: the read fails. |
| Subordinate_Node_Types | BACnetARRAY[N] of BACnetNodeType | O | no | no | 0 |
| Subordinate_Relationships | BACnetARRAY[N] of BACnetRelationship | O | no | no | 0 |
| Default_Subordinate_Relationship | BACnetRelationship | O | no | no | 0 |
| Represents | BACnetDeviceObjectReference | O | no | no | No default: the read fails. |
| Audit_Level | BACnetAuditLevel | O1 | not in profile | not in profile | No default: the read fails. |
| Auditable_Operations | BACnetAuditOperationFlags | O1 | not in profile | not in profile | No default: the read fails. |
| Tags | BACnetARRAY[N] of BACnetNameValue | O | no | no | No default: the read fails. |
| Profile_Location | CharacterString | O | no | no | "" |
| Profile_Name | CharacterString | O | no | no | "" |