1 Scope

This specification was created by a joint working group of the OPC Foundation and BACnet Interest Group Europe. It defines an OPC UA Information Model to represent the BACnet architectural models.

Typical use cases include but are not limited to SCADA connectivity, enterprise integration of building automation networks and data and interfacing between industry and building automation.

OPC Foundation

The OPC Foundation defines standards for online data exchange between automation systems. They address access to current data (OPC DA), alarms and events (OPC A&E) and historical data (OPC HDA). Those standards are successfully applied in industrial automation.

The new OPC Unified Architecture (OPC UA) unifies the existing standards and brings them to state-of-the-art technology using service-oriented architecture (SOA). Platform-independent technology allows the deployment of OPC UA beyond current OPC applications only running on Windows-based PC systems. OPC UA can also run on embedded systems as well as Linux / UNIX based enterprise systems. The provided information can be generically modelled and therefore arbitrary information models can be provided using OPC UA.

BACnet Interest Group Europe

The BACnet Interest Group Europe (BIG-EU) was founded in 1998 as an association under German law and meanwhile represents BACnet activities all over Europe.

BIG-EU has more than 115 members: vendors, project designer, system integrators and end-users of BACnet systems.

The working group marketing (WG-M) organizes events like forums, trade-shows, etc. while the working group technique supports technical activities like specifications or enhancements of the BACnet standard.

BIG-EU closely collaborates with the ASHRAE/SSPC-135 and BACnet International with the BACnet Testing Laboratories working group BTL-WG.

The BACnet Academy offers BACnet training courses all over Europe.

The BACnet Europe Journal issued twice a year by the BACnet Interest Group Europe is a popular magazine about European BACnet activities.

2 Normative References

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments and errata) applies.

ANSI/ASHRAE Standard 135-2012 A Data Communication Protocol for Building Automation and Control Networks

ISO16484-5:2012 Building automation and control systems (BACS) – Part 5: Data communication

ANSI/ASHRAE Standard 135.1-2011 Method of Test for Conformance to BACnet

ISO16484-6:2009 Building automation and control systems (BACS) – Part 6: Data communication conformance testing

BTL Implementation Guidelines v34 Document designed for implementers of BACnet. This document enumerates many common mistakes made by first time implementers of BACnet. (available from www.bacnetinternational.org)

Addendum 135-2012al Specify Best Practices for Gateway Design (available from www.bacnet.org/Addenda/index.html)

OPC 10000-1, OPC Unified Architecture - Part 1: Overview and Concepts

OPC 10000-1

OPC 10000-2, OPC Unified Architecture - Part 2: Security Model

OPC 10000-2

OPC 10000-3, OPC Unified Architecture - Part 3: Address Space Model

OPC 10000-3

OPC 10000-4, OPC Unified Architecture - Part 4: Services

OPC 10000-4

OPC 10000-5, OPC Unified Architecture - Part 5: Information Model

OPC 10000-5

OPC 10000-6, OPC Unified Architecture - Part 6: Mappings

OPC 10000-6

OPC 10000-7, OPC Unified Architecture - Part 7: Profiles

OPC 10000-7

OPC 10000-8, OPC Unified Architecture - Part 8: Data Access

OPC 10000-8

OPC 10000-9, OPC Unified Architecture - Part 9: Alarms and Conditions

OPC 10000-9

3 Terms, definitions, and conventions

3.1 Use of terms

Defined terms of OPC UA specifications, types and their components defined in OPC UA specifications and in this specification are highlighted with italic in this document.

BACnet related terms and names are always used together with BACnet.

3.2 Terms used from BACnet standard

3.2.1 Command Prioritization

In building automation systems, multiple entities may control and manipulate an object. There may be a need to arbitrate between a schedule program, manual operation by the facility manager, and from the service technician. For so-called commandable properties (like the present value of output object types), BACnet uses a 16-level prioritization schema where 1 is the highest priority (Manual Life Safety) and 16 is the lowest. The value in the highest priority slot takes precedence over all others. A default value is taken from the property “Relinquish_Default” in case all slots in the priority array are uninitialized (NULL).

3.2.2 Change of Value (COV)

Change-of-Value is used to inform client processes about changes of values spontaneously without the need for polling. For analog data a hysteresis (COV-increment) is provided as a special property to allow reducing the traffic and only notify relevant changes.

3.3 OPC UA for BACnet Information Model terms

3.3.1 BACnetUaMapper

The software that implements the mapping between BACnet and OPC UA defined in this specification.

3.4 Abbreviations and symbols

3.5 Conventions used in this document

3.5.1 Conventions for Node descriptions

Node definitions are specified using tables (See Table 1)

Attributes are defined by providing the Attribute name and a value, or a description of the value.

References are defined by providing the ReferenceType name, the BrowseName of the TargetNode and its NodeClass.

If the TargetNode is a component of the Node being defined in the table the Attributes of the composed Node are defined in the same row of the table. That implies that the referenced Node has a HasModelParent Reference with the Node defined in the Table as TargetNode (see OPC 10000-3 for the definition of ModelParents).

The DataType is only specified for Variables; “[<number>]” indicates a single-dimensional array, for multi-dimensional arrays the expression is repeated for each dimension (e.g. [2][3] for a two-dimensional array). For all arrays the ArrayDimensions is set as identified by <number> values. If no <number> is set, the corresponding dimension is set to 0, indicating an unknown size. If no number is provided at all the ArrayDimensions can be omitted. If no brackets are provided, it identifies a scalar DataType and the ValueRank is set to the corresponding value (see OPC 10000-3). In addition, ArrayDimensions is set to null or is omitted. If it can be Any or ScalarOrOneDimension, the value is put into “{<value>}”, so either “{Any}” or “{ScalarOrOneDimension}” and the ValueRank is set to the corresponding value (see OPC 10000-3) and the ArrayDimensions is set to null or is omitted. In Table 2 examples are given.

The TypeDefinition is specified for Objects and Variables.

The TypeDefinition column specifies a NodeId of a TypeDefinitionNode, i.e. the specified Node points with a HasTypeDefinition Reference to the corresponding TypeDefinitionNode. The symbolic name of the NodeId is used in the table.

The Other of the referenced component is provided by specifying the symbolic name of the rule in the Other column. In the AddressSpace, the Node shall use a HasOther Reference to point to the corresponding Other Object.

If the NodeId of a DataType is provided, the symbolic name of the Node representing the DataType shall be used.

Nodes of all other NodeClasses cannot be defined in the same table; therefore only the used ReferenceType, their NodeClass and their BrowseName are specified. A reference to another of this document points to their definition.

If no components are provided, the DataType, TypeDefinition and Other columns may be omitted and only a Comment column is introduced to point to the Node definition.

Components of Nodes can be complex, i.e. containing components by themselves. The TypeDefinition, NodeClass, DataType and Other can be derived from the type definitions, and the symbolic name can be created as defined in 3.5.2.1. Therefore those containing components are not explicitly specified; they are implicitly specified by the type definitions.

3.5.2 NodeIds and BrowseNames

3.5.2.1 NodeIds

The NodeIds of all Nodes described in this document are only symbolic names. Annex A defines the actual NodeIds.

The symbolic name of each Node defined in this document is its BrowseName, or, when it is part of another Node, the BrowseName of the other Node, a “.”, and the BrowseName of itself. In this case “part of” means that the whole has a 0:HasProperty or HasComponent Reference to its part. Since all Nodes not being part of another Node have a unique name in this document, the symbolic name is unique.

The namespace for this specification is defined in Annex A. The NamespaceIndex for all NodeIds defined in this specification is server specific and depends on the position of the namespace URI in the server namespace table.

Note: This specification does not only define concrete Nodes, but also requires that some Nodes have to be generated, for example one for each device type available in the frame application. The NodeIds of those Nodes are server-specific, including the Namespace. But the NamespaceIndex of those Nodes cannot be the NamespaceIndex used for the Nodes defined by this specification, because they are not defined by this specification but generated by the Server.

3.5.2.2 BrowseNames

The text part of the BrowseNames for all Nodes defined in this specification is specified in the tables defining the Nodes. The NamespaceIndex for all BrowseNames defined in this specification is server specific and depends on the position of the namespace URI defined in this specification in the server namespace table.

If the BrowseName is not defined by this specification, a namespace index prefix like ‘0:EngineeringUnits’ is added to the BrowseName. This is typically necessary if a Property of another specification is overwritten or used in the OPC UA types defined in this specification. Table 260 provides a list of namespaces used in this specification.

3.5.3 Common Attributes

3.5.3.1 General

For all Nodes specified in this specification, the Attributes named in Table 3 shall be set as specified in the table.

3.5.3.2 Objects

For all Objects specified in this specification, the Attributes named in Table 4 shall be set as specified in the table.

3.5.3.3 Variables

For all Variables specified in this specification, the Attributes named in Table 5 shall be set as specified in the table.

3.5.3.4 VariableTypes

For all VariableTypes specified in this specification, the Attributes named in Table 6 shall be set as specified in the table.

4 General information to BACnet and OPC UA

4.1 Introduction to BACnet

4.1.1 General

BACnet (Building Automation and Control networks) is a data-communication protocol specifically designed for building automation applications.

1987 the ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) founded the committee 135 to create an open and neutral communication protocol for building automation. First published in 1995 the BACnet standard is under continuous maintenance by SSPC 135. A public review process before the formal approval assures acceptance by the industry or interested parties.

While starting as a national American standard BACnet has become a world-wide standard and was accepted by ISO as the standards ISO 16484-5 and ISO 16484-6.

The general architecture of BACnet describes three main parts, the BACnet data link layers, the BACnet objects and the BACnet application services.

4.1.2 BACnet Data-Link-Layers

BACnet supports a total of 9 different network media (data-link-layer).

Those are:

BACnet Ethernet (ISO 8802-3 aka Layer-2 Ethernet, rarely used)

ARCnet (Network or EIA-485, rarely used)

LonTalk (any media supported by LonTalk, rarely used)

MS/TP (Master/Slave Token Passing) based on EIA-485 (serial networks, commonly used)

PTP (Point-to-Point) based on EIA-232 (serial connection, rarely used)

BACnet/IP (based upon IPv4 and UDP communication, commonly used)

BACnet/IPv6 (based upon IPv6 and UDP communication, rarely used)

ZIGBEE (wireless mesh networks, rarely used)

BACnet/SecureConnect (based upon TCP / websocket based communication, rarely used but expected to be commonly used in the future)

4.1.3 BACnet Objects

BACnet models the data of building automation components as objects. Those include Analog, Binary and Multi-State Input, Output and Value Objects, primitive data, the representation of devices, counters, calendar and scheduling, trend-logging, alarming, life-safety and access control objects as well as objects to represent a building structure (groups, structured views).

Objects consist of properties to represent the data associated to the specific information. This includes text information like the name and description, the technical address of the data, the present value, units, alarm-limits as well as specific building automation functionality like command priorities, elapsed active time or change-of-state counting. Due to the de-central approach of BACnet a client can request all information from a device representing data as a server.

4.1.4 BACnet Application Services

The BACnet application services allow access to the objects and provide functions to interact between BACnet applications in a network. Another set of network services on layer 3 of the ISO/OSI model provide routing functions between the different data-link-layers as well as exchanging information about network security.

Application services include object access like reading, writing and change-of-value. Other services provide file-transfer, alarm information, remote device and network management and virtual terminal functions.

To assure interoperability between applications BACnet specifies a PICS (Protocol Implementation Conformance Statement) document. A PICS is a self-declaration by the vendor of a BACnet device and describes which parts of BACnet are supported by the implementation.

4.1.5 BACnet Device Profiles

BACnet devices may support one of the 8 device profiles specified for better interoperability.

The profiles are:

4.2 Introduction to OPC Unified Architecture

4.2.1 General

The main use case for OPC standards is the online data exchange between devices and HMI or SCADA systems using Data Access functionality. In this use case the device data is provided by an OPC server and is consumed by an OPC client integrated into the HMI or SCADA system. OPC DA provides functionality to browse through a hierarchical namespaces containing data items and to read, write and to monitor these items for data changes. The classic OPC standards are based on Microsoft COM/DCOM technology for the communication between software components from different vendors. Therefore classic OPC server and clients are restricted to Windows PC based automation systems.

OPC UA incorporates all features of classic OPC standards like OPC DA, A&E and HDA but defines platform independent communication mechanisms and generic, extensible and object-oriented modelling capabilities for the information a system wants to expose.

The OPC UA network communication part defines different mechanisms optimized for different use cases. The first version of OPC UA is defining an optimized binary TCP protocol for high performance intranet communication as well as a mapping to accepted internet standards like Web Services. The abstract communication model does not depend on a specific protocol mapping and allows adding new protocols in the future. Features like security, access control and reliability are directly built into the transport mechanisms. Based on the platform independence of the protocols, OPC UA servers and clients can be directly integrated into devices and controllers.

The OPC UA Information Model provides a standard way for Servers to expose Objects to Clients. Objects in OPC UA terms are composed of other Objects, Variables and Methods. OPC UA also allows relationships to other Objects to be expressed.

The set of Objects and related information that an OPC UA Server makes available to Clients is referred to as its AddressSpace. The elements of the OPC UA Object Model are represented in the AddressSpace as a set of Nodes described by Attributes and interconnected by References. OPC UA defines eight classes of Nodes to represent AddressSpace components. The classes are Object, Variable, Method, ObjectType, DataType, ReferenceType and View. Each NodeClass has a defined set of Attributes.

This specification makes use of three essential OPC UA NodeClasses: Objects, Methods and Variables.

Objects are used to represent components of a system. An Object is associated to a corresponding ObjectType that provides definitions for that Object.

Methods are used to represent commands or services of a system.

Variables are used to represent values. Two categories of Variables are defined, Properties and DataVariables.

Properties are Server-defined characteristics of Objects, DataVariables and other Nodes. Properties are not allowed to have Properties defined for them. An example for Properties of Objects is the Object_Identifier Property of a BACnetObjectType.

DataVariables represent the contents of an Object. DataVariables may have component DataVariables. This is typically used by Servers to expose individual elements of arrays and structures. This specification uses DataVariables to represent data like the Present_Value of a BACnetAnalogInput Object.

4.2.2 Graphical Notation

OPC UA defines a graphical notation for an OPC UA AddressSpace. It defines graphical symbols for all NodeClasses and how different types of References between Nodes can be visualized. Figure 1 shows the symbols for the six NodeClasses used in this specification. NodeClasses representing types always have a shadow.

Figure 2 shows the symbols for the ReferenceTypes used in this specification. The Reference symbol is normally pointing from the source Node to the target Node. The only exception is the HasSubType Reference. The most important References like HasComponent, 0:HasProperty, HasTypeDefinition and HasSubType have special symbols avoiding the name of the Reference. For other ReferenceTypes or derived ReferenceTypes the name of the ReferenceType is used together with the symbol.

Figure 3 shows a typical example for the use of the graphical notation. Object_A and Object_B are instances of the ObjectType_Y indicated by the HasTypeDefinition References. The ObjectType_Y is derived from ObjectType_X indicated by the HasSubType Reference. The Object_A has the components Variable_1, Variable_2 and Method_1.

To describe the components of an Object on the ObjectType the same NodeClasses and References are used on the Object and on the ObjectType like for ObjectType_Y in the example. The instance Nodes used to describe an ObjectType are instance declaration Nodes.

To provide more detailed information for a Node, a subset or all Attributes and their values can be added to a graphical symbol.

4.3 Use Cases

The following use cases illustrate the usage of the information model. Not all necessary Objects must be realized within a concrete OPC UA Server. These use cases cover a system that is BACnet client and OPC UA server. The use cases for the other direction (OPC UA client and BACnet server) are not covered in the current version and may be added in a future version.

Observation

Observation comprises reading and monitoring data such as present value, trend log and events of BACnet objects available in an existing BACnet network from a BACnet OPC UA Server.

The representation of BACnet internetworks, devices their objects and properties is consistent across BACnet OPC UA server products.

The BACnet OPC UA server may restrict the exposed information from a BACnet internetwork through configuration and/or user autorization.

Example 1: Enterprise integration (monitoring energy consumption, comparing trends)

Example 2: Multi domain integration (building automation with industrial automation)

Operation

Operation inherits the functionality of observation and extends it.

Operation comprises writing data such as set points, selecting mode of operation or acknowledge alarms through the BACnet OPC UA server.

Example 1: Enterprise integration (writing set points)

Example 2: Multi domain integration (building automation with industrial automation) (writing operation mode)

Engineering (Configuration / Maintenance)

Engineering inherits the functionality of operation and extends it.

Engineering comprises of configuring BACnet objects through a BACnet OPC UA Server like configuring modes of operation, enabling/disabling alarms and configuring schedules.

Example1: The properties of BACnet devices may be configured by OPC UA clients during the installation or engineering phase.

Example2: If room assignments or names change, the object representation may need to be updated accordingly. The OPC UA mapping model may be used to access and modify this information.

The following Figure 4 shows the use case diagram.

5 BACnet OPC UA Model Overview

5.1 Modelling concepts

BACnet defines a list of object types where all common properties are repeated for each type. Type hierarchies and inheritance are not used in BACnet.

Since OPC UA supports type hierarchies, inheritance and aggregation, these concepts are used to avoid duplicated definitions in the OPC UA representation of BACnet. The example of a BACnet analog input object type is used in this overview chapter to describe how the different concepts are used in this mapping specification.

The following three concepts are used to reduce duplicated definitions in this specification

Type hierarchies and inheritance is used to map common BACnet properties on a base type or different levels of a type hierarchy.

BACnet properties that match existing OPC UA Attributes or Properties are mapped to existing OPC UA concepts like BACnet Object_Name to OPC UA Attribute BrowseName or the BACnet properties Units, Min_Pres_Value and Max_Pres_Value to OPC UA Properties of the AnalogItemType.

Aggregation is used if BACnet properties can be logically grouped or a group of BACnet properties is used in different OPC UA ObjectTypes across the type hierarchy.

Figure 5 shows an example for type hierarchies and inheritance used to map the BACnet Analog Input object type to OPC UA. The BACnet properties are shown in the same order as defined in the BACnet standard.

The BACnet properties defined for all BACnet object types are mapped to the BACnetObjectType. This abstract OPC UA ObjectType is used as root for the BACnet object type hierarchy.

The BACnet properties defined for all BACnet analog object types are mapped to the abstract BACnetAnalogType. The remaining property is mapped to the concrete OPC UA ObjectType BACnetAnalogInputType.

Figure 6 shows an example for mapping BACnet properties to OPC UA built-in concepts like TypeDefinition, Attributes or standard OPC UA Properties.

The BACnet property Object_Type is mapped to the TypeDefinition of the OPC UA Object instance.

The BACnet properties Object_Name, Description and Update_Interval are mapped to the OPC UA Attributes BrowseName, Description and MinSamplingInterval.

The BACnet properties Units, Min_Pres_Value and Max_Pres_Value are mapped the OPC UA Properties EngineeringUnits and EURange of the OPC UA VariableType AnalogItemType.

Figure 7 shows an example how groups of BACnet properties are integrated through aggregation.

The BACnet properties used to configure event reporting like Event_State, Notification_Class, Event_Enabled and Notify_Type are grouped in the OPC UA ObjectType BACnetEventReportingType. An instance of this type is then aggregates as OPC UA Object EventReporting in the OPC UA Object AnalogInput1.

The BACnet properties used for the event algorithm in the event reporting like High_Limit, Low_Limit or Deadband are aggregated in the OPC UA Object EventAlgorithm. Since different event algorithms can be used in event reporting, they build their own event algorithm type hierarchy with the base ObjectType BACnetEventAlgorithmType and the derived types like BACnetOutOfRangeAlgorithmType that is used in the BACnetAnalogInputType.

The BACnet properties used to configure fault evaluation like Reliability and Reliability_Evaluation_Inhibit are grouped in the OPC UA ObjectType BACnetFaultEvaluationType. An instance of this type is then aggregates as OPC UA Object FaultEvaluation in the OPC UA Object AnalogInput1.

5.2 Model Overview

Figure 8 depicts the main ObjectTypes of the OPC UA for BACnet information model and their relationship. The drawing is not intended to be complete.

The boxes in this drawing show the ObjectTypes used in this specification as well as some elements from other specifications. The upper grey box shows the OPC UA core ObjectType from which the OPC UA for BACnet information model ObjectTypes are derived and some VariableTypes used in the BACnet ObjectTypes.

The left grey box in the second level shows the main ObjectTypes that this specification introduces. They represent corresponding BACnet object types. A type hierarchy is used whenever identical components are used in different BACnet object types.

The right grey box in the second level shows the ObjectTypes used for grouping of BACnet features. These groupings are used in the OPC UA for BACnet information model ObjectTypes shown in the left grey box.

Figure 9 provides an example for the mapping of a BACnet Analog Input object type to an OPC UA ObjectType.

The left grey box shows the list of BACnet properties of the BACnet Analog Input object type.

The middle grey box shows an instance of an OPC UA BACnetAnalogInput ObjectType.

The right grey box shows the OPC UA ObjectTypes used to represent a BACnet Analog Input object type.

Most of the BACnet properties are mapped to OPC UA Properties using the BACnet property name as OPC UA BrowseName. They are either Properties of the Object directly or Properties of the EventReporting Object.

The following BACnet properties are mapped to existing OPC UA information.

Object_Name is mapped to the BrowseName of the OPC UA Object

Object_Type is mapped to the type definition of the OPC UA Object

Description is mapped to the OPC UA Attribute Description of the OPC UA Object

Present_Value, Units, Min_Pres_Value and Max_Pres_Value are mapped to an OPC UA AnalogItemType Variable with the name Present_Value

Update is mapped to the OPC UA Attribute MinimumSamplingInterval of the OPC UA Variable Present_Value

5.3 Event and alarm handling

5.4 Character Set handling

All character string information provided through this information model is solely ISO 10646 (UTF-8). A gateway application may convert character string information into other character sets according to the BACnet device capabilities.

6 OPC UA ObjectTypes used for structuring the address space

6.1 BACnetInternetworkType

6.1.1 General

This OPC UA ObjectType represents a BACnet Internetwork. A BACnet Internetwork consists of one or more BACnet Devices and may be setup using different BACnet Data-Link-Layers connected through BACnet router devices.

6.1.2 ObjectType definition

The BACnetInternetworkType is formally defined in Table 7.

The BACnetObjectType is an abstract type and cannot be used directly.

6.1.3 ObjectType Description

6.1.3.1 Objects <BACnetDeviceName>

List of BACnet devices contained in the internetwork. The BACnetUaMapper may limit the list to the devices configured in the BACnetUaMapper or configured through the Methods NetworkScan, AddDevice and RemoveDevice.

6.1.3.2 Method TranslateBACnetIds

TranslateBACnetIds allows an OPC UA Client to request the NodeIds of OPC UA Objects representing BACnet objects by passing in the BACnet object identifier for the device and the object. This enables a Client to translate the BACnet address into an OPC UA NodeId.

Signature

	TranslateBACnetIds(
		[in] 	BACnetDeviceObjectPropertyReference[]	BACnetIds
		[out]	NodeId[]						OpcUaIds
		);
	

Method Result Codes

6.1.3.3 Method NetworkScan

NetworkScan allows an OPC UA Client to update the BACnet device list by using the BACnet Who-Is and I-Am services.

Signature

	NetworkScan (
		[in]	0:UInt32					WaitTimeInSeconds
		[in]	0:Boolean					ApplyRange
		[in]	0:UInt32					DeviceRangeLow
		[in]	0:UInt32					DeviceRangeHigh
		[out]	BaseDataType []				DeviceAddressBindings
		[out]	0:UInt32 []					MaxAPDULengthAccepted
		[out]	BACnetSegmentation []			SegmentationSupported
		[out]	0:UInt16 []					VendorIdentifier
		);
	

Method Result Codes

6.1.3.4 Method AddDeviceByAddress

AddDeviceByAddress allows adding a BACnet device with a known address to BACnetInternetworkType Object. The necessary information can be retrieved from the Method NetworkScan. The BACnetUaMapper may limit access to this method to administrative users.

Signature

	AddDeviceByAddress (
		[in]	BaseDataType	Address
		);
	

Method Result Codes

6.1.3.5 Method GetDeviceIdList

GetDeviceIdList provides a list of known devices. The necessary information can be updated using the Method NetworkScan. The BACnetUaMapper may limit access to this method to administrative users.

Signature

	GetDeviceIdList (
		[out]	BACnetObjectIdentifier[]	BACnetDeviceIds,
		[out]	NodeId[]				OpcUaObjectIds
		);
	

Method Result Codes

6.1.3.6 Method AddDeviceById

AddDeviceById allows adding a BACnet device with a known internal Id to BACnetInternetworkType Object. The necessary information can be retrieved from the Method GetDeviceIdList. The BACnetUaMapper may limit access to this method to administrative users.

Signature

	AddDeviceById (
		[in]	NodeId	DeviceObject
		);
	

Method Result Codes

6.1.3.7 Method TimeSynchronization

This Method is used to update the time of the BACnet devices in the network. See B.3 for more details. This method is only provided if the BACnetUaMapper is a BACnet time master.

Signature

	TimeSynchronization (
		[in]	UtcTime	Time
		);
	

Method Result Codes

7 OPC UA ObjectTypes representing BACnet object types

7.1 BACnetObjectType

7.1.1 General

This ObjectType defines the super type for all OPC UA ObjectTypes representing BACnet object types in an OPC UA Address Space. It introduces two properties common for all BACnet object types. Figure 10 shows an overview for the BACnetObjectType with its Properties and related ObjectTypes. It is formally defined in Table 8.

7.1.2 ObjectType definition

The BACnetObjectType is formally defined in Table 8.

The BACnetObjectType is an abstract type and cannot be used directly.

7.1.3 ObjectType Description

7.1.3.1 Standard OPC UA Object Attributes

The following BACnet properties are mapped to existing OPC UA Object Attributes.

Object_Name is mapped to the BrowseName of the OPC UA Object

Object_Type is mapped to the type definition of the OPC UA Object

Description is mapped to the OPC UA Attribute Description of the OPC UA Object

7.1.3.2 Variable Object_Identifier

This OPC UA Property represents the BACnet property Object_Identifier.

It is the unique address within the BACnet device. It consists of a BACnet object type and instance number. The BACnetObjectIdentifier DataType is defined in 10.2.1.

7.1.3.3 Variable Profile_Name

This OPC UA Property represents the BACnet property Profile_Name.

A profile defines a set of additional properties, behavior, and/or requirements for this object beyond those specified by BACnet.

7.2 BACnetObjectTypeUnknown

7.2.1 General

This ObjectType is used to represent object types not covered by this specification (standard or proprietary object types).

7.2.2 ObjectType definition

The BACnetObjectTypeUnknown is formally defined in Table 9.

7.2.3 ObjectType Description

7.2.3.1 Variable Object_Type

This OPC UA Property, of DataType BACnetObjectTypeEnum, represents the BACnet property Object_Type. The BACnetObjectTypeEnum DataType is defined in 10.4.21.

The property is an enumeration that describes the BACnet object type of the type not covered by this specification. This information is contained in the OPC UA type definition NodeId for the BACnet object types mapped in this specification.

7.3 BACnetDeviceType

7.3.1 General

This OPC UA ObjectType represents a BACnet Device object type. There is exactly one BACnetDeviceType in each BACnet Device. The Object_Identifier property of the BACnetDeviceType identifies the device and is unique throughout the BACnet internetwork. This ObjectType exposes standard BACnet services through OPC UA methods. These methods may be invoked to manage the configuration of the BACnet Device.

Figure 11 shows an overview for the BACnetDeviceType with its Properties and related ObjectTypes. It is formally defined in Table 10.

7.3.2 ObjectType definition

The BACnetDeviceType is formally defined in Table 10.

The BACnetDeviceType ObjectType is a concrete type and can be used directly.

The components of the BACnetDeviceType have additional subcomponents which are defined in Table 11.

7.3.3 ObjectType Description

7.3.3.1 EventNotifier Attribute

If the BACnet device object contains BACnet notification class objects, the SubscribeToEvents flag is set in the EventNotifier OPC UA Attribute.

7.3.3.2 Object Object_List

Object_List gathers the references to BACnet objects of the BACnet device provided through the BACnet property Object_List.

The OPC UA Property Object_List on the Object_List object, of DataType BACnetObjectIdentifier[], represents the BACnet property Object_List. The BACnetObjectIdentifier DataType is defined in 10.2.1. It contains a list of BACnet objects within the device.

The list of BACnetObjectTypes on the Object_List object contains the list of BACnet objects within the device. The list may be limited through configuration of the BACnetUaMapper.

7.3.3.3 Object Structured_Object_List

Structured_Object_List gathers the references to all BACnet structured view objects of the BACnet device provided through the BACnet property Structured_Object_List.

The OPC UA Property Structured_Object_List on the Structured_Object_List object, of DataType BACnetObjectIdentifier[], represents the BACnet property Structured_Object_List. The BACnetObjectIdentifier DataType is defined in 10.2.1. It contains a list of BACnet structured view objects within the device.

The list of BACnetStructuredViewTypes on the Structured_Object_List object contains the list of BACnet structured view objects within the device. The list may be limited through configuration of the BACnetUaMapper.

7.3.3.4 Object TimeManagement

This optional OPC UA Object, of type BACnetTimeManagementType, provides localized time and date information to consumers of the device object.

If an automatic time synchronization master is available, the special subtype BACnetAutomaticTimeSynchronizationMasterType is used.

7.3.3.5 Object BackupRestore

This optional OPC UA Object, of type BACnetBackupRestoreType, provides backup and restore status to consumers of the device object. This status provides information about the last restore time, backup failures, preparation and completion times, and so on.

7.3.3.6 Object MstpMaster

This optional OPC UA Object, of type BACnetMstpMasterType, describes paramters that are relevant if the device objects functions as a master on an MS/TP network.

7.3.3.7 Object DeviceRestart

This optional OPC UA Object, of type BACnetDeviceRestartType, provides information related to restarting the device. The last restart time and the set of devices that are notified when the device is restarted are provided by this object.

7.3.3.8 Notifier Objects

OPC UA Objects that have the EventNotifier Attribute set to SubscribeToEvents are so called event notifiers. They can be used by OPC UA Clients to subscribe for Events from the OPC UA Server. The OPC UA ReferenceType HasNotifier is used to build an event notifier tree starting from the Server Object.

BACnetNotifierType Objects like instances of BACnetNotificationClassTypes are used together with instances of the BACnetDeviceType to represent the OPC UA event notifier hierarchy starting from the Server object.

Figure 12 shows an example of BACnet objects referencing each other with BACnetObjectIdentifiers and the representation with OPC UA Objects and References. The example contains a BACnet Device object, one Analog Input object that creates alarms and therefore references a Notification Class object.

7.3.3.9 Variable System_Status

This OPC UA Property, of DataType BACnetDeviceStatus, represents the BACnet property System_Status. The BACnetDeviceStatus DataType is defined in 10.4.9.

The property is an enumeration that describes the current operating state of the device. Some example states are “operational”, “non-operational”, “backup in progress”, and so forth.

7.3.3.10 Variable Vendor_Name

This OPC UA Property, of DataType String, represents the BACnet property Vendor_Name.

This property identifies the manufacturer of the BACnet device.

7.3.3.11 Variable Vendor_Identifier

This OPC UA Property, of DataType UInt16, represents the BACnet property Vendor_Identifier.

This property represents a unique identification code, assigned by ASHRAE. The code is used to identify proprietary extensions to the protocol.

7.3.3.12 Variable Model_Name

This OPC UA Property, of DataType String, represents the BACnet property Model_Name.

This property identifies the model name of the BACnet device.

7.3.3.13 Variable Serial_Number

This OPC UA Property, of DataType String, represents the BACnet property Serial_Number.

This property identifies the serial number of the BACnet device.

7.3.3.14 Variable Firmware_Revision

This OPC UA Property, of DataType String, represents the BACnet property Firmware_Revision.

This property identifies the firmware installed in the BACnet device.

7.3.3.15 Variable Application_Software_Version

This OPC UA Property, of DataType String, represents the BACnet property Application_Software_Version.

This property identifies the application software version installed in the BACnet device.

7.3.3.16 Variable Location

This optional OPC UA Property, of DataType String, represents the BACnet property Location.

This property identifies the physical location of the BACnet device.

7.3.3.17 Variable Protocol_Version

This OPC UA Property, of DataType UInteger, represents the BACnet property Protocol_Version.

This property identifies the major version of the BACnet protocol supported by this device.

7.3.3.18 Variable Protocol_Revision

This OPC UA Property, of DataType UInteger, represents the BACnet property Protocol_Revision.

7.3.3.19 Variable Protocol_Services_Supported

This OPC UA Property, of DataType BACnetServicesSupportedBits, represents the BACnet property Protocol_Services_Supported. The BACnetServicesSupportedBits DataType is defined in 10.3.6.

The BACnetServicesSupportedBits identifies the standardized protocol services that are executed by the implementation of the protocol on this device. See the BACnet specification for minimum supported service requirements.

7.3.3.20 Variable Protocol_Object_Types_Supported

This OPC UA Property, of DataType BACnetObjectTypeSupportedBits, represents the BACnet property Protocol_Object_Types_Supported. The BACnetObjectTypeSupportedBits DataType is defined in 10.3.5.

This property identifies the standardized BACnet object types (like analog inputs, binary outputs, calendars, and so on) that can be represented by this device’s implementation of the BACnet protocol. The minimum set of supported objects shall be at least Analog Input, Analog Output, Analog Value, Binary Input, Binary Output, and Binary Value.

7.3.3.21 Variable Max_APDU_Length_Accepted

This OPC UA Property, of DataType UInteger, represents the BACnet property Max_APDU_Length_Accepted.

This property describes the maxium number of octets that may be packaged into a single application layer protocol data unit. The data type of this variable is an unsigned integer and its value shall be greater than or equal to 50.

7.3.3.22 Variable Segmentation_Supported

This OPC UA Property, of DataType BACnetSegmentation, represents the BACnet property Segmentation_Supported. The BACnetSegmentation DataType is defined in 10.4.30.

The BACnetSegmentation is an enumeration that indicates whether the BACnet device supports message segmentation and, if so, whether it supports segmented transmission, reception, or both.

7.3.3.23 Variable Max_Segments_Accepted

This optional OPC UA Property, of DataType UInteger, represents the BACnet property Max_Segments_Accepted.

The Max_Segments_Accepted property indicates the maximum number of segments of an APDU that the device will accept.

7.3.3.24 Variable APDU_Segment_Timeout

This optional OPC UA Property, of DataType UInteger, represents the BACnet property APDU_Segment_Timeout.

The APDU_Segment_Timeout property indicates the amount of time (in milliseconds) between retransmission of an APDU segment. See the BACnet specification for recommended default values and best practices.

7.3.3.25 Variable APDU_Timeout

This OPC UA Property, of DataType UInteger, represents the BACnet property APDU_Timeout.

The APDU_Timeout property indicates the amount of time (in milliseconds) between retransmissions of an APDU that requires acknowledgement, but for which no acknowledgement has been received. See the BACnet specification for recommended default values and best practices.

7.3.3.26 Variable Number_Of_APDU_Retries

This OPC UA Property, of DataType UInteger, represents the BACnet property Number_Of_APDU_Retries.

The Number_Of_APDU_Retries property indicates the maximum number of times that an ADPU is retransmitted. See the BACnet specification for recommended default values and best practices.

7.3.3.27 Variable Device_Address_Binding

This OPC UA Property, containing an array of DataType BACnetAddressBinding, represents the BACnet property Device_Address_Binding. The BACnetAddressBinding DataType is defined in 10.5.3.

The BACnetAddressBinding data type identify the actual device address that will be used when the remote device must be accessed using a BACnet service request. See the BACnet specification for rules related to zero network-number addresses and empty lists.

7.3.3.28 Variable Database_Revision

This OPC UA Property, of DataType UInteger, represents the BACnet property Database_Revision.

The Database_Revision property describes a logical revision number for the device database. The revision is incremented when an object is created, an object is deleted, an object’s name is changed, an object’s Object_Identifier property is changed, or a restore is performed. See the BACnet specification for exceptions.

7.3.3.29 Variable Active_COV_Subscriptions

This OPC UA Property, containing an array of DataType BACnetCOVSubscription, represents the BACnet property Active_COV_Subscriptions. The BACnetCOVSubscription DataType is defined in 10.5.4.

The BACnetCOVSubscription value provides a network-visible indication of those COV subscriptions that are active at any given time. When a COV subscription is created using the BACnet COV subscription services, a ew entry is added to the Active_COV_Subscriptions list. The entry is removed when the subscription is terminated.

7.3.3.30 Method CreateObject

This method represents the BACnet service CreateObject. It is used to create a new instance of an object. The BACnet properties of standard objects created with this Method may be initialized in two ways: initial values may be provided as part of the CreateObject Method call or values may be written to the newly created object using OPC UA Write.

Signature

	CreateObject (
		[in]	BACnetObjectIdentifier		ObjectSpecifier
	[in]	0:KeyValuePair[]			ListOfInitialValues
		);
	

Method Result Codes

7.3.3.31 Method DeleteObject

This method represents the BACnet service DeleteObject. It can be used to delete objects that may be created and deleted dynamically.

Signature

	DeleteObject (
		[in]	BACnetObjectIdentifier		ObjectIdentifier
		);
	

Method Result Codes

7.3.3.32 Method ReinitializeDevice

This method represents the BACnet service ReinitializeDevice. It is used to instruct a remote device to reboot itself (cold start), reset itself to some predefined initial state (warm start), or to control the backup or restore procedure. Resetting or rebooting a device is primarily initiated by a human operator for diagnostic purposes.

Remark: Since the method contains the Password, this method should only be available if the connection is encrypted.

Signature

	ReinitializeDevice (
		[in]	BACnetReinitializedStateofDevice ReinitializedStateofDevice
		[in]	0:String					Password
		);
	

Method Result Codes

7.3.3.33 Method DeviceCommunicationControl

This method represents the BACnet service DeviceCommunicationControl. It is used to instruct a remote device to stop initiating communication and optionally stop responding to communication for a specified duration of time.

Remark: Since the method contains the Password, this method should only be available if the connection is encrypted.

Signature

	DeviceCommunicationControl (
		[in]	0:UInt16					TimeDurationInMinutes
		[in]	BACnetDeviceCommunicationEnabled	EnableDisable
		[in]	0:String					Password
		);
	

Method Result Codes

7.3.3.34 Method TextMessage

This method represents the BACnet services ConfirmedTextMessage and UnconfirmedTextMessage.

The UnconfirmedTextMessage service is used by a client BACnet-user to send a text message to one or more BACnet devices. This service may be broadcast, multicast, or addressed to a single recipient. This service may be used in cases where confirmation that the text message was received is not required. Messages may be prioritized into normal or urgent categories. In addition, a given text message may optionally be classified by a numeric class code or class identification string. This classification may be used by receiving BACnet devices to determine how to handle the text message. For example, the message class might indicate a particular output device on which to print text or a set of actions to take when the text message is received. In any case, the interpretation of the class is a local matter.

The ConfirmedTextMessage service is used by a client BACnet-user to send a text message to another BACnet device. This service is not a broadcast or multicast service. This service may be used in cases when confirmation that the text message was received is required. The confirmation does not guarantee that a human operator has seen the message. Messages may be prioritized into normal or urgent categories. In addition, a given text message may be optionally classified by a numeric class code or class identification string. This classification may be used by the receiving BACnet device to determine how to handle the text message. For example, the message class might indicate a particular output device on which to print text or a set of actions to take when the text is received. In any case, the interpretation of the class is a local matter.

Signature

	TextMessage (
		[in]	0:Boolean				SendUnconfirmed
		[in]	BACnetObjectIdentifier		TextMessageSourceDevice
		[in]	BACnetMessageClass		MessageClass
		[in]	BACnetMessagePriority		MessagePriority
		[in]	0:String				Message
		);
	

Method Result Codes

7.3.3.35 Method AddDeviceAddressBindings

This Method adds entries to the BACnet property Device_Address_Binding.

Signature

	AddDeviceAddressBindings (
		[in]	BACnetAddressBinding []		AddressBindings
		[out]	0:UInt32					FirstFailedElementNumber
		);
	

Method Result Codes

7.3.3.36 Method RemoveDeviceAddressBindings

This Method removes entries from the BACnet property Device_Address_Binding.

Signature

	RemoveDeviceAddressBindings (
		[in]	BACnetAddressBinding[]			AddressBindings
		[out]	0:UInt32					FirstFailedElementNumber
		);
	

Method Result Codes

7.4 BACnetAnalogType

7.4.1 General

This OPC UA ObjectType defines the super type for all OPC UA ObjectTypes that represent BACnet Analog object types in an OPC UA Address Space.

Figure 13 shows an overview for the BACnetAnalogType with its Properties and related ObjectTypes. It is formally defined in Table 12.

7.4.2 ObjectType definition

The BACnetAnalogType is formally defined in Table 12.

The BACnetAnalogType is an abstract type and cannot be used directly.

The components of the BACnetAnalogType have additional subcomponents which are defined in Table 13.

7.4.3 ObjectType Description

7.4.3.1 Variable Present_Value

This OPC UA Variable, of DataType Float, indicates the current value, in engineering units, of the input being measured. The Present_Value Variable shall be writable when Out_Of_Service is true.

This OPC UA AnalogItemType Variable represents the BACnet properties Present_Value, Min_Pres_Value, Max_Pres_Value, Units and Update_Interval. The OPC UA VariableType AnalogItemType is defined in OPC 10000-8. It defines the OPC UA Properties EURange, EngineeringUnits and InstrumentRange.

The following list provides the BACnet property and the mapping to the corresponding data member in the OPC UA AnalogItem.

Present_Value represented by Value Attribute of the Variable.

Min_Pres_Value represented by Low part of EURange Property of the Variable. If the optional BACnet property Min_Pres_Value is not present, the EURange Property should not be provided.

Max_Pres_Value represented by the High part of EURange Property of the Variable. If the optional BACnet property Max_Pres_Value is not present, the EURange Property should not be provided.

Units represented by the EngineeringUnits Property of the Variable. The mapping of BACnet units to OPC UA units is defined in 11.

Update_Interval represented by MinSamplingInterval Attribute of the Variable.

7.4.3.2 Variable Out_Of_Service

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

It is an indication of whether or not the physical input that the object represents is not in service. While Out_Of_Service is True, Present_Value and Reliability may be changed to any value as a means of simulation and/or testing.

7.4.3.3 Variable Status_Flags

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

It represents four Boolean flags that represent the general health of a BACnetAnalogType. The flags are IN_ALARM, FAULT, OVERRIDDEN, and OUT_OF_SERVICE.

7.4.3.4 Variable COV_Increment

This OPC UA Property, of type Float, represents the BACnet property COV_Increment.

It shall specify the minimum change in the BACnet property Present_Value that will cause a Change of Value notification to be issued to BACnet clients that have subscribed to Change of Value events.

7.4.3.5 Variable Resolution

This OPC UA Property, of DataType Float, represents the BACnet property Resolution.

It indicates the smallest recognizable change in Present_Value in engineering units.

7.4.3.6 Object EventReporting

The EventReporting Object contains status and configuration information for the event reporting of BACnetAnalogTypes and their subtypes. 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 BACnetOutOfRangeAlgorithmType and ModellingRule Mandatory if used in the BACnetAnalogType or one of its subtypes. The BACnetOutOfRangeAlgorithmType is defined in 8.9.3.

On the EventAlgorithm instance of the BACnetOutOfRangeAlgorithmType the BACnet property High_Limit is mapped to pHighLimit, the BACnet property Low_Limit is mapped to LowLimit, the BACnet property Deadband is mapped to pDeadband and the BACnet property Limit_Enable is mapped to LimitEnable.

7.4.3.7 Object FaultEvaluation

The FaultEvaluation Object contains status and configuration information for the fault evaluation of the BACnetAnalogType. 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.

7.5 BACnetAnalogInputType

7.5.1 General

This OPC UA ObjectType represents the BACnet object type Analog Input. An analog input converts a continuously variable input signal into a discrete value that can be processed by a computer system.

Figure 14 shows an overview for the BACnetAnalogInputType with its Properties and related ObjectTypes. It is formally defined in Table 14.

7.5.2 ObjectType definition

The BACnetAnalogInputType ObjectType is formally defined in Table 14.

The BACnetAnalogInputType ObjectType is a concrete type and can be used directly.

7.5.3 ObjectType Description

7.5.3.1 Variable Device_Type

This OPC UA Property, of DataType String, represents the BACnet property Device_Type.

It is a text description of the physical device connected to the analog input.

7.6 BACnetAnalogOutputType

7.6.1 General

This OPC UA ObjectType represents the BACnet object type Analog Output. An analog output converts a discrete value into a continuously variable output signal.

Figure 15 shows an overview for the BACnetAnalogOutput with its Properties and related ObjectTypes. It is formally defined in Table 15.

7.6.2 ObjectType definition

The BACnetAnalogOutput ObjectType is formally defined in Table 15.

The BACnetAnalogOutput ObjectType is a concrete type and can be used directly.

7.6.3 ObjectType Description

7.6.3.1 Variable Device_Type

This OPC UA Property, of DataType String, represents the BACnet property Device_Type.

It is a text description of the physical device connected to the analog output.

7.6.3.2 Variable Priority_Array

This OPC UA Property, of DataType BACnetPriorityValue [16], represents the BACnet property Priority_Array. The BACnetPriorityValue DataType is defined in 10.6.4.

It is an array that contains prioritized values that are in effect for this object. See 3.2.1 for details on command prioritization.

7.6.3.3 Variable Relinquish_Default

This OPC UA Property, of DataType Float, represents the BACnet property Relinquish_Default.

It is the default value to be used for the Present_Value when all command priority values in the Priority_Array have a NULL value. See 3.2.1 for details on command prioritization.

7.7 BACnetAnalogValueType

7.7.1 General

This OPC UA ObjectType represents the BACnet object type Analog Value. This is a control system parameter that resides in the memory of the BACnet Device.

Figure 16 shows an overview for the BACnetAnalogValueType with its Properties and related ObjectTypes. It is formally defined in Table 16.

7.7.2 ObjectType definition

The BACnetAnalogValueType ObjectType is formally defined in Table 16.

The BACnetAnalogValueType ObjectType is a concrete type and can be used directly.

7.7.3 ObjectType Description

7.7.3.1 Variable Priority_Array

This OPC UA Property, of DataType BACnetPriorityValue [16], represents the BACnet property Priority_Array. The BACnetPriorityValue DataType is defined in 10.6.4.

It is an array that contains prioritized commands that are in effect for this object. See 3.2.1 for details on command prioritization.

7.7.3.2 Variable Relinquish_Default

This OPC UA Property, of DataType 0:Float, represents the BACnet property Relinquish_Default.

It is the default value to be used for the Present_Value when all command priority values in the Priority_Array have a NULL value. See 3.2.1 for details on command prioritization.

7.8 BACnetBinaryType

7.8.1 General

This OPC UA ObjectType defines the super type for all OPC UA ObjectTypes that represent BACnet Binary object types in an OPC UA Address Space.

Figure 17 shows an overview for the BACnetBinaryType with its Properties and related ObjectTypes. It is formally defined in Table 17.

7.8.2 ObjectType definition

The BACnetBinaryType ObjectType is formally defined in Table 17.

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

7.8.3 ObjectType Description

7.8.3.1 Variable Present_Value

This OPC UA Variable, of DataType 0:Boolean, represents the logical state of the BACnet Binary Input object. The logical state of the Input shall be either Inactive or Active.

This OPC UA TwoStateDiscreteType Variable represents the BACnet properties Present_Value, Inactive_Text and Active_Text. The OPC UA VariableType TwoStateDiscreteType is defined in OPC 10000-8. It defines the OPC UA Properties TrueState and FalseState.

The following list provides the BACnet property and the mapping to the corresponding data member in the OPC UA TwoStateDiscrete item.

Present_Value represented by Value Attribute of the Variable.

Active_Text represented by the TrueState Property of the Variable.

Inactive_Text represented by the FalseState Property of the Variable.

7.8.3.2 Variable Out_Of_Service

This OPC UA Property, of DataType 0:Boolean, represents the BACnet property Out_Of_Service.

It is an indication of whether or not the physical input that the object represents is not in service. While the Out_Of_Service property is True, the Present_Value and Reliability properties may be changed to any value as a means of simulation and/or testing.

7.8.3.3 Variable Status_Flags

This OPC UA Property, 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.

7.8.3.4 Object ChangeOfState

The ChangeOfState Object contains BACnet properties related to counting the change of state of BACnetBinaryType Objects. The BACnetChangeOfStateCountType is defined in 8.1. The Object is optional and is not present if change of state counting is not activated for the BACnet object.

7.8.3.5 Object ElapsedActiveTime

The ElapsedActiveTime Object contains BACnet properties related to the elapsed active time of BACnetBinaryType Objects. The BACnetElapsedActiveTimeType is defined in 8.7. The Object is optional and is not present if this feature is not available for the BACnet object.

7.8.3.6 Object EventReporting

The EventReporting Object contains status and configuration information for the event reporting of BACnetBinaryType Objects. 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.

7.8.3.7 Object FaultEvaluation

The FaultEvaluation Object contains status and configuration information for the fault evaluation of the BACnetBinaryType. 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.

7.9 BACnetBinaryInputType

7.9.1 General

This OPC UA ObjectType represents the BACnet object type Binary Input. A binary input converts one or more discrete input signals into a value that can be processed by a computer system.

Figure 18 shows an overview for the BACnetBinaryInputType with its Properties and related ObjectTypes. It is formally defined in Table 18.

7.9.2 ObjectType definition

The BACnetBinaryInputType ObjectType is formally defined in Table 18.

The BACnetBinaryInputType ObjectType is a concrete type and can be used directly.

The components of the BACnetBinaryInputType have additional subcomponents which are defined in Table 19.

7.9.3 ObjectType Description

7.9.3.1 EventReporting Object override

The instance declaration Object EventReporting overrides definitions of the BACnetEventReportingType.

The EventAlgorithm component is changed to TypeDefinition BACnetChangeOfStateAlgorithmType and ModellingRule Mandatory if used in the BACnetBinaryInputType. The BACnetChangeOfStateAlgorithmType is defined in 8.10.

On the EventAlgorithm instance of the BACnetChangeOfStateAlgorithmType, the DataType of the Alarm_Values Property is changed to 0:Boolean.

The BACnet property Alarm_Value of the BACnet object type Binary Input is mapped to the AlarmValues Property of the BACnetChangeOfStateAlgorithmType.

7.9.3.2 Variable Device_Type

This OPC UA Property, of DataType String, represents the BACnet property Device_Type.

It is a text description of the physical device connected to the binary input.

7.9.3.3 Variable Polarity

This OPC UA Property, of DataType BACnetPolarity, represents the BACnet property Polarity. The BACnetPolarity DataType is defined in 10.4.22.

It indicates the relationship between the physical state of the Input and the logical state represented by the Present_Value property.

7.10 BACnetBinaryOutputType

7.10.1 General

This OPC UA ObjectType represents the BACnet object type Binary Output. A binary output converts a value into one or more discrete output signals.

Figure 19 shows an overview for the BACnetBinaryOutputType with its Properties and related ObjectTypes. It is formally defined in Table 20.

7.10.2 ObjectType definition

The BACnetBinaryOutputType ObjectType is formally defined in Table 20.

The BACnetBinaryOutputType ObjectType is a concrete type and can be used directly.

The components of the BACnetBinaryOutputType have additional subcomponents which are defined in Table 21.

7.10.3 ObjectType Description

7.10.3.1 EventReporting Object override

The instance declaration Object EventReporting overrides definitions of the BACnetEventReportingType.

The EventAlgorithm component is changed to TypeDefinition BACnetCommandFailureAlgorithmType and ModellingRule Mandatory if used in the BACnetBinaryOutputType. The BACnetCommandFailureAlgorithmType is defined in 8.10.

7.10.3.2 Variable Device_Type

This OPC UA Property, of DataType String, represents the BACnet property Device_Type.

It is a text description of the physical device connected to the binary output.

7.10.3.3 Variable Polarity

This OPC UA Property, of DataType BACnetPolarity, represents the BACnet property Polarity. The BACnetPolarity DataType is defined in 10.4.22.

It indicates the relationship between the physical state of the Ouput and the logical state represented by the Present_Value property.

7.10.3.4 Variable Priority_Array

This OPC UA Property, of DataType BACnetPriorityValue [16], represents the BACnet property Priority_Array. The BACnetPriorityValue DataType is defined in 10.6.4.

It is an array that contains prioritized commands that are in effect for this object. See 3.2.1 for details on command prioritization.

7.10.3.5 Variable Relinquish_Default

This OPC UA Property, of DataType 0:Boolean, represents the BACnet property Relinquish_Default.

It is the default value to be used for the Present_Value when all command priority values in the Priority_Array have a NULL value. See 3.2.1 for details on command prioritization.

7.10.3.6 Variable Minimum_Off_Time

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

It represents the minimum number of seconds that the Present_Value shall remain in the Inactive state after a write to the Present_Value property causes that property to assume the Inactive state.

7.10.3.7 Variable Minimum_On_Time

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

It represents the minimum number of seconds that the Present_Value shall remain in the Active state after a write to the Present_Value property causes the property to assume the Active state.

7.10.3.8 Variable Feedback_Value

This OPC UA Property, of type 0:Boolean, is an indication of the actual value of the entity controlled by Present_Value.

7.11 BACnetBinaryValueType

7.11.1 General

This OPC UA ObjectType represents a BACnet Binary Value object type. A binary value is a control system parameter that resides in the memory of the BACnet Device and may be one of only two states.

Figure 20 shows an overview for the BACnetBinaryValueType with its Properties and related ObjectTypes. It is formally defined in Table 22.

7.11.2 ObjectType definition

The BACnetBinaryValueType ObjectType is formally defined in Table 22.

The BACnetBinaryValueType ObjectType is a concrete type and can be used directly.

The components of the BACnetBinaryValueType have additional subcomponents which are defined in Table 23.

7.11.3 ObjectType Description

7.11.3.1 EventReporting Object override

The instance declaration Object EventReporting overrides definitions of the BACnetEventReportingType.

The EventAlgorithm component is changed to TypeDefinition BACnetChangeOfStateAlgorithmType and ModellingRule Mandatory if used in the BACnetBinaryValueType. The BACnetChangeOfStateAlgorithmType is defined in 8.10.

On the EventAlgorithm instance of the BACnetChangeOfStateAlgorithmType, the DataType of the Alarm_Values Property is changed to 0:Boolean.

The BACnet property Alarm_Value of the BACnet object type Binary Value is mapped to the AlarmValues Property of the BACnetChangeOfStateAlgorithmType.

7.11.3.2 Variable Priority_Array

This OPC UA Property, of DataType BACnetPriorityValue [16], represents the BACnet property Priority_Array. The BACnetPriorityValue DataType is defined in 10.6.4.

It is an array that contains prioritized commands that are in effect for this object. See 3.2.1 for details on command prioritization.

7.11.3.3 Variable Relinquish_Default

This OPC UA Property, of DataType 0:Boolean, represents the BACnet property Relinquish_Default.

It is the default value to be used for the Present_Value when all command priority values in the Priority_Array have a NULL value. See 3.2.1 for details on command prioritization.

7.11.3.4 Variable Minimum_Off_Time

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

It represents the minimum number of seconds that the Present_Value shall remain in the Inactive state after a write to the Present_Value property causes that property to assume the Inactive state.

7.11.3.5 Variable Minimum_On_Time

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

It represents the minimum number of seconds that the Present_Value shall remain in the Active state after a write to the Present_Value property causes the property to assume the Active state.

7.12 BACnetMultiStateType

7.12.1 General

This OPC UA ObjectType defines the super type for all OPC UA ObjectTypes that represent BACnet MultiState object types in an OPC UA Address Space.

Figure 21 shows an overview for the BACnetMultiStateType with its Properties and related ObjectTypes. It is formally defined in Table 24.

7.12.2 ObjectType definition

The BACnetMultiStateType ObjectType is formally defined in Table 24.

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

7.12.3 ObjectType Description

7.12.3.1 Variable Present_Value

This OPC UA Property, of DataType 0:UInteger, reflects the logical state of the input.

This OPC UA MultiStateDiscreteType Variable represents the BACnet properties Present_Value, State_Text and Number_Of_States. The OPC UA VariableType MultiStateDiscreteType is defined in OPC 10000-8. It defines the OPC UA Property EnumStrings.

The following list provides the BACnet property and the mapping to the corresponding data member in the OPC UA multistate discrete item.

Present_Value represented by Value Attribute of the Variable.

State_Text and Number_Of_States represented by the EnumStrings Property of the Variable. If the optional BACnet property State_Text is not present, the EnumStrings property is filled with State_1 to State_N strings where the N and the number of strings are defined by Number_Of_States.

7.12.3.2 Variable Out_Of_Service

This OPC UA Property, of DataType 0:Boolean, represents the BACnet property Out_Of_Service.

It is an indication of whether or not the physical input that the object represents is not in service. While the Out_Of_Service property is True, the Present_Value and Reliability properties may be changed to any value as a means of simulation and/or testing.

7.12.3.3 Variable Status_Flags

This OPC UA Property, 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 a BACnetMultiStateType. The flags are IN_ALARM, FAULT, OVERRIDDEN, and OUT_OF_SERVICE.

7.12.3.4 Object EventReporting

The EventReporting Object contains status and configuration information for the event reporting of BACnetMultiStateType Objects. The BACnetEventReportingType is defined in 0. The Object is optional and is not present if event generation is not activated for the BACnet object.

7.12.3.5 Object FaultEvaluation

The FaultEvaluation Object contains status and configuration information for the fault evaluation of the BACnetMultiStateType. 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.

7.13 BACnetMultiStateInputType

7.13.1 General

This OPC UA ObjectType represents the BACnet object type MultiState Input. A multi-state input includes a Present_Value variable whose value represents a state set by a locally defined algorithm.

Figure 22 shows an overview for the BACnetMultiStateInputType with its Properties and related ObjectTypes. It is formally defined in Table 25.

7.13.2 ObjectType definition

The BACnetMultiStateInputType ObjectType is formally defined in Table 25.

The BACnetMultiStateInputType ObjectType is a concrete type and can be used directly.

The components of the BACnetMultiStateInputType have additional subcomponents which are defined in Table 26.

7.13.3 ObjectType Description

7.13.3.1 EventReporting Object override

The instance declaration Object EventReporting overrides definitions of the BACnetEventReportingType.

The EventAlgorithm component is changed to TypeDefinition BACnetChangeOfStateAlgorithmType and ModellingRule Mandatory if used in the BACnetMultiStateInputType. The BACnetChangeOfStateAlgorithmType is defined in 8.10.

On the EventAlgorithm instance of the BACnetChangeOfStateAlgorithmType, the DataType of the Alarm_Values Property is changed to 0:UInteger array.

The BACnet property Alarm_Values of the BACnet object type Multi State Input is mapped to the AlarmValues Property of the BACnetChangeOfStateAlgorithmType.

7.13.3.2 FaultEvaluation Object override

The instance declaration Object FaultEvaluation overrides definitions of the BACnetFaultEvaluationType.

The FaultAlgorithm component is changed to TypeDefinition BACnetFaultStateAlgorithmType if used in the BACnetMultiStateInputType. The BACnetFaultStateAlgorithmType is defined in 8.25.

On the FaultAlgorithm instance of the BACnetFaultStateAlgorithmType, DataType of the Fault_Values Property is changed to 0:UInteger array.

7.13.3.3 Variable Device_Type

This OPC UA Property, of DataType String, represents the BACnet property Device_Type.

It provides a text description of the physical device connected to the multi-state input.

7.14 BACnetMultiStateOutputType

7.14.1 General

This OPC UA ObjectType represents the BACnet object type MultiState Output. A multi-state output includes a Present_Value variable whose value represents the desired state of a physical output. The states and algorithms used to generate them are locally defined.

Figure 23 shows an overview for the BACnetMultiStateOutputType with its Properties and related ObjectTypes. It is formally defined in Table 27.

7.14.2 ObjectType definition

The BACnetMultiStateOutputType ObjectType is formally defined in Table 27.

The BACnetMultiStateOutputType ObjectType is a concrete type and can be used directly.

The components of the BACnetMultiStateOutputType have additional subcomponents which are defined in Table 28.

7.14.3 ObjectType Description

7.14.3.1 EventReporting Object override

The instance declaration Object EventReporting overrides definitions of the BACnetEventReportingType.

The EventAlgorithm component is changed to TypeDefinition BACnetCommandFailureAlgorithmType and ModellingRule Mandatory if used in the BACnetMultiStateOutputType. The BACnetCommandFailureAlgorithmType is defined in 8.10.

7.14.3.2 Variable Device_Type

This OPC UA Property, of DataType String, represents the BACnet property Device_Type.

It is a text description of the physical device connected to the multi-state output.

7.14.3.3 Variable Priority_Array

This OPC UA Property, of DataType BACnetPriorityValue [16], represents the BACnet property Priority_Array. The BACnetPriorityValue DataType is defined in 10.6.4.

It is an array that contains prioritized commands that are in effect for this object. See 3.2.1 for details on command prioritization.

7.14.3.4 Variable Relinquish_Default

This OPC UA Property, of DataType 0:UInteger, represents the BACnet property Relinquish_Default.

It is the default value to be used for the Present_Value when all command priority values in the Priority_Array have a NULL value. See 3.2.1 for details on command prioritization.

7.14.3.5 Variable Feedback_Value

This OPC UA Property, of type 0:UInteger, is an indication of the actual value of the entity controlled by Present_Value.

7.15 BACnetMultiStateValueType

7.15.1 General

This OPC UA ObjectType represents a BACnet Multi-state Value object type. A multi-state value is a control system parameter that resides in the memory of the BACnet Device and includes a Present_Value variable whose value represents the object state. The states and algorithms used to generate them are locally defined.

Figure 24 shows an overview for the BACnetMultiStateValueType with its Properties and related ObjectTypes. It is formally defined in Table 29.

7.15.2 ObjectType definition