This OPC UA ObjectType represents an object which monitors a property of a referenced object and serializes the timestamp as local time and value of the property into an internal buffer when a pre-defined condition is met. The serialization may be invoked on a periodic basis, using a trigger or upon a change of value.

Figure 29 shows an overview for the BACnetLogType with its Properties and related ObjectTypes. It is formally defined in Table 36.

Figure 29 – BACnetLogType overview

The BACnetLogType ObjectType is formally defined in Table 36.

Table 36 – BACnetLogType Definition

Attribute		Value
BrowseName		BACnetLogType
IsAbstract		True
References	NodeClass		BrowseName	DataType	TypeDefinition	Other
Subtype of the BACnetObjectType defined in 7.1.
0:HasProperty	Variable		Status_Flags	BACnetStatusFlags	0:PropertyType	M
0:HasProperty	Variable		Enable	0:Boolean	0:PropertyType	M
0:HasProperty	Variable		Start_Time	BACnetDateTime	0:PropertyType	O
0:HasProperty	Variable		Stop_Time	BACnetDateTime	0:PropertyType	O
0:HasProperty	Variable		Stop_When_Full	0:Boolean	0:PropertyType	M
0:HasProperty	Variable		Buffer_Size	0:UInt32	0:PropertyType	M
0:HasProperty	Variable		Record_Count	0:UInt32	0:PropertyType	M
0:HasProperty	Variable		Total_Record_Count	0:UInt32	0:PropertyType	M
0:HasProperty	Variable		Records_Since_Notification	0:UInt32	0:PropertyType	O
0:HasComponent	Object		FaultEvaluation		BACnetFault Evaluation Type	M
0:HasComponent	Object		EventReporting		BACnetEvent ReportingType	M

The BACnetLogType ObjectType is an abstract type and cannot be used directly.

The components of the BACnetLogType have additional subcomponents which are defined in Table 37.

Table 37 – BACnetLogType Additional Subcomponents

BrowsePath	References	NodeClass	BrowseName	DataType	TypeDefinition	Others
EventReporting	0:HasComponent	Object	EventAlgorithm		BACnetBufferReadyAlgorithmType	M

This OPC UA Variable, of DataType BACnetStatusFlags, represents the BACnet property Status_Flags. The BACnetStatusFlags DataType is defined in 10.3.7.

It represents four 0:Boolean flags that represent the general health of an analog input. The flags are IN_ALARM, FAULT, OVERRIDDEN, and OUT_OF_SERVICE.

This OPC UA Property, of DataType Boolean, represents the BACnet property Enable.

When the Enable value is true, logging is enabled. When the Enable variable value is false, logging is not enabled. Logging occurs if and only if the Enable variable value is true and the device Local_Time.

This OPC UA Property, of DataType BACnetDateTime, represents the BACnet property Start_Time. The BACnetDateTime DataType is defined in 10.5.8.

The Start_Time value indicates the date and time at or after which logging shall be enabled by this variable. The variable is O, and if unspecified is ignored for the purpose of determining whether or not logging is enabled. If Start_Time specifies a time and date that is equal to or later than the Stop_Time then logging shall be disabled.

This OPC UA Property, of DataType BACnetDateTime, represents the BACnet property Stop_Time. The BACnetDateTime DataType is defined in 10.5.8.

The Stop_Time value indicates the date and time at or after which logging shall be disabled by this variable. The variable is O, and if unspecified is ignored for the purpose of determining whether or not logging is disabled. If Stop_Time indicates a date and time that is earlier than the Start_Time, then logging is disabled.

This OPC UA Property, of DataType Boolean, represents the BACnet property Stop_When_Full.

When the Stop_When_Full value is true, logging shall cease when the serialization buffer is full. When logging ceases because the next event would fill the buffer, an event indicating that the buffer is full is logged and the Enable variable shall be set false.

This OPC UA Property, of DataType UInt32, represents the BACnet property Buffer_Size.

The Buffer_Size value indicates the number of records that may be contained by the buffer.

This OPC UA Property, of DataType UInt32, represents the BACnet property Record_Count.

The Record_Count value indicates the number of records that are currently present in the buffer. When a value of zero is written to this variable, all records in the buffer shall be deleted and the Records_Since_Notification variable value shall be reset to zero.

This OPC UA Property, of DataType UInt32, represents the BACnet property Total_Record_Count.

The Total_Record_Count value indicates the total number of records that have been logged since the object was created. When the count is incremented past the maximum 32-bit integer value, the next value of the variable shall be 1.

This OPC UA Property, of DataType UInt32, represents the BACnet property Records_Since_Notification.

The Records_Since_Notification indicates the number of records that have been logged since the buffer was last cleared (notification), or since the beginning of the logging process if no notification has been delivered.

The FaultEvaluation Object contains status and configuration information for the fault evaluation of the BACnetLoopType. The BACnetFaultEvaluationType is defined in 8.23. The Object is optional and is not present if fault evaluation is not activated for the BACnet object.

The EventReporting Object contains status and configuration information for the event reporting of BACnetTrendLogType. The BACnetEventReportingType is defined in 8.8. The Object is optional and is not present if event generation is not activated for the BACnet object.

The instance declaration Object EventReporting overrides definitions of the BACnetEventReportingType.

The EventAlgorithm component is changed to TypeDefinition BACnetFloatingLimitAlgorithmType and ModellingRule Mandatory if used in the BACnetLoopType. The BACnetBufferReadyAlgorithmType is defined in 8.14.

The Properties TimeDelay and TimeDelayNormal are set to 0 and shall be read only since they do not exist on a BACnet Trend Log object.

On the EventAlgorithm instance of the BACnetBufferReadyAlgorithmType the BACnet property Notification_Threshold is mapped to Threshold. The BACnet property Last_Notify_Record is mapped to PreviousCount.