Positive Integer Value

A Positive Integer Value object holds a whole number that is zero or greater, with engineering units. Use it for counts, ratings and other values that are never negative and can be larger than a small state number. Clients read it and, if the device allows, write it.

Typical uses

• Run-time hours of equipment
• Number of occupants in a room
• Target speed in rpm
• Event or start counter
• Rated capacity of a unit

Key properties

Property	What it holds
Present_Value	The unsigned whole number the object holds.
Units	The engineering units of the value.
COV_Increment	How far Present_Value must move before a subscribed client is notified. Present only when the object supports COV.
Priority_Array	Optional. Present only when the value is commandable; sixteen priority slots.
Low_Limit / High_Limit	Optional limits for alarms. The object reports off-normal when the value passes one, after the time delay.

How it behaves

The object is commandable only if you give it a priority array. When it reports intrinsic events, the standard pairs it with the UNSIGNED_OUT_OF_RANGE algorithm, which has a deadband for the return to normal. COV notifications go out when Present_Value changes by COV_Increment or on any change to Status_Flags.

With the CAS BACnet Stack

Enable it with the STACK_OPTION_OBJECT_TYPE_POSITIVE_INTEGER_VALUE build option and add each object with BACnetStack_AddObject. Serve Present_Value with the callback you register with BACnetStack_RegisterCallbackGetPropertyUnsignedInteger and, if clients may write it, the BACnetStack_RegisterCallbackSetPropertyUnsignedInteger callback. The object becomes commandable once you enable both PriorityArray and RelinquishDefault. To arm alarms, enable alarms for the object and call BACnetStack_SetIntrinsicUnsignedOutOfRangeAlgorithm; do not use BACnetStack_SetIntrinsicUnsignedRangeAlgorithm, which is the no-deadband variant meant for other types. Call BACnetStack_UpdateValue whenever the value you serve changes, so COV, trend logs and alarms see it. The stack has no fault out-of-range setter for this type: BACnetStack_SetFaultOutOfRangeAlgorithmReal refuses it.

Related object types

Integer Value, Analog Value, Accumulator

Properties

The properties ASHRAE 135-2024 clause 12.44 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	""
Present_Value	Unsigned	R1	yes	no (yes while Out_Of_Service is true)	No default: value-not-initialized. Once Priority_Array and Relinquish_Default are enabled, built by the stack from the priority array your callbacks serve.
Status_Flags	BACnetStatusFlags	R	yes	no	Built by the stack from your callbacks.
Event_State	BACnetEventState	O4	no	no	0
Reliability	BACnetReliability	O	no	no (yes while Out_Of_Service is true)	0
Out_Of_Service	Boolean	O	no	no	false
Units	BACnetEngineeringUnits	R	yes	no	95 (no units)
Priority_Array	BACnetARRAY[16] of BACnetOptionalUnsigned	O2	no	no	Built by the stack from your callbacks.
Relinquish_Default	Unsigned	O2	no	no	No default: value-not-initialized until a callback or a client write supplies one.
COV_Increment	Unsigned	O3	no	no	0
Time_Delay	Unsigned	O4,6	no	no	0
Notification_Class	Unsigned	O4,6	no	no	0
High_Limit	Unsigned	O4,6	no	no	0
Low_Limit	Unsigned	O4,6	no	no	0
Deadband	Unsigned	O4,6	no	no	0
Limit_Enable	BACnetLimitEnable	O4,6	no	no	An empty bit string.
Event_Enable	BACnetEventTransitionBits	O4,6	no	no	An empty bit string.
Acked_Transitions	BACnetEventTransitionBits	O4,6	no	no	An empty bit string.
Notify_Type	BACnetNotifyType	O4,6	no	no	0
Event_Time_Stamps	BACnetARRAY[3] of BACnetTimeStamp	O4,6	no	no	No default: the read fails.
Event_Message_Texts	BACnetARRAY[3] of CharacterString	O6	no	no	""
Event_Message_Texts_Config	BACnetARRAY[3] of CharacterString	O6	no	no	""
Event_Detection_Enable	Boolean	O4,6	no	no	false
Event_Algorithm_Inhibit_Ref	BACnetObjectPropertyReference	O6	no	no	No default: the read fails.
Event_Algorithm_Inhibit	Boolean	O6,7	no	no	false
Time_Delay_Normal	Unsigned	O6	no	no	0
Reliability_Evaluation_Inhibit	Boolean	O8	no	no	false
Min_Pres_Value	Unsigned	O	no	no	0
Max_Pres_Value	Unsigned	O	no	no	0
Resolution	Unsigned	O	no	no	0
Property_List	BACnetARRAY[N] of BACnetPropertyIdentifier	R	yes	no	Held by the stack.
Fault_High_Limit	Unsigned	O9	no	no	0
Fault_Low_Limit	Unsigned	O9	no	no	0
Current_Command_Priority	BACnetOptionalUnsigned	O2	no	no	Built by the stack from your callbacks.
Value_Source	BACnetValueSource	O10,12,14	no	no	No default: the read fails.
Value_Source_Array	BACnetARRAY[16] of BACnetValueSource	O11,13	no	no	No default: the read fails.
Last_Command_Time	BACnetTimeStamp	O11,13	no	no	No default: the read fails.
Command_Time_Array	BACnetARRAY[16] of BACnetTimeStamp	O13	no	no	No default: the read fails.
Audit_Level	BACnetAuditLevel	O15	not in profile	not in profile	No default: the read fails.
Auditable_Operations	BACnetAuditOperationFlags	O15	not in profile	not in profile	No default: the read fails.
Audit_Priority_Filter	BACnetOptionalPriorityFilter	O15	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	""