According to the BACnet protocol documentation:

Defines a standardized object whose properties represent the externally visible characteristics of any form of feedback control loop. Flexibility is achieved by providing three independent gain constants with no assumed values for units. The appropriate gain units are determined by the details of the control algorithm, which is a local matter.

Objects of type loop have the following properties:

•ackedTransitions

•action

•bias

•controlledVariableReference

•controlledVariableUnits

•controlledVariableValue

•covIncrement

•deadband

•derivativeConstant

•derivativeConstantUnits

•description

•errorLimit

•eventAlgorithmInhibit

•eventAlgorithmInhibitRef

•eventDetectionEnable

•eventEnable

•eventMessageTexts

•eventMessageTextsConfig

•eventState

•eventTimeStamps

•integralConstant

•integralConstantUnits

•lowDiffLimit

•manipulatedVariableReference

•maximumOutput

•minimumOutput

•notificationClass

•notifyType

•objectIdentifier

•objectName

•objectType

•outOfService

•outputUnits

•presentValue

•priorityForWriting

•profileLocation

•profileName

•propertyList

•proportionalConstant

•proportionalConstantUnits

•reliability

•reliabilityEvaluationInhibit

•setpoint

•setpointReference

•statusFlags

•tags

•timeDelay

•timeDelayNormal

•updateInterval