Elevator Group

An Elevator Group collects the lifts or the escalators that one supervisory controller runs together. It lists the group’s members and gives the group an ID and a machine room. A client reads it to see how a bank of lifts is organised.

Typical uses

• A bank of passenger lifts
• A pair of escalators in a mall
• Landing-call status for a lift group
• Find which machine room serves a group

Key properties

Property	What it holds
Group_ID	The number that identifies this group.
Machine_Room_ID	Refers to the machine room that houses the group.
Group_Members	The Lift or Escalator objects in the group.
Group_Mode	The operating mode of a lift group, such as normal or down peak.
Landing_Calls	Calls waiting at landings, on a group that supports landing call status.

How it behaves

The object is not commandable and has no intrinsic event algorithm. A group holds either lifts or escalators, not both.

With the CAS BACnet Stack

Enable it with the STACK_OPTION_OBJECT_TYPE_ELEVATOR_GROUP build option. Do not use BACnetStack_AddObject for this type. Call BACnetStack_AddElevatorGroupObject with the machine room ID, the group ID, whether it holds lifts or escalators, and whether it supports landing call status. Add it before its lifts or escalators, which join it through BACnetStack_AddLiftOrEscalatorObject. The stack holds Object_Identifier, Machine_Room_ID, Group_ID and Group_Members. You serve Object_Name through the callback you register with BACnetStack_RegisterCallbackGetPropertyCharacterString and Group_Mode through the BACnetStack_RegisterCallbackGetPropertyEnumerated callback. Landing calls use the BACnetStack_RegisterCallbackGetListElevatorGroupLandingCallStatus callback.

Related object types

Escalator, Group, Lift, Positive Integer Value, Structured View

Properties

The properties ASHRAE 135-2024 clause 12.58 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	""
Machine_Room_ID	BACnetObjectIdentifier	R	yes	no	Held by the stack.
Group_ID	Unsigned8	R	yes	no	Held by the stack; a Get callback that answers wins.
Group_Members	BACnetARRAY[N] of BACnetObjectIdentifier	R	yes	no	Held by the stack.
Group_Mode	BACnetLiftGroupMode	O1	no	no	0
Landing_Calls	BACnetLIST of BACnetLandingCallStatus	O1	no	no	No default: the read fails.
Landing_Call_Control	BACnetLandingCallStatus	O1	no	no	No default: the read fails.
Property_List	BACnetARRAY[N] of BACnetPropertyIdentifier	R	yes	no	Held by the stack.
Audit_Level	BACnetAuditLevel	O2	not in profile	not in profile	No default: the read fails.
Auditable_Operations	BACnetAuditOperationFlags	O2	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	""