1 Scope

For the communication between different machines, manufacturer independent information models are required. For woodworking machinery, these information models are based on OPC UA, a communication framework developed and provided by the OPC Foundation. While OPC UA provides the technology for the transfer of information, the definition which information is transferred in which form is defined in Companion Specifications.

This documentation defines a Companion Specification for general information regarding woodworking machines. The intention is that ObjectTypes which can be used for several machines and applications are defined only once.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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.

OPC 10000-1, OPC Unified Architecture - Part 1: Overview and Concepts – V1.05.02

OPC 10000-1

OPC 10000-2, OPC Unified Architecture - Part 2: Security Model – V1.05.02

OPC 10000-2

OPC 10000-3, OPC Unified Architecture - Part 3: Address Space Model – V1.05.02

OPC 10000-3

OPC 10000-4, OPC Unified Architecture - Part 4: Services – V1.05.00

OPC 10000-4

OPC 10000-5, OPC Unified Architecture - Part 5: Information Model – V1.05.02

OPC 10000-5

OPC 10000-6, OPC Unified Architecture - Part 6: Mappings – V1.05.01

OPC 10000-6

OPC 10000-7, OPC Unified Architecture - Part 7: Profiles – V1.05.02

OPC 10000-7

OPC 10000-100, OPC Unified Architecture - Part 100: Devices – V1.04

OPC 10000-100

OPC 40001-1, OPC UA for Machinery - Part 1: Basic Building Blocks – V1.02.0

http://www.opcfoundation.org/UA/Machinery/

OPC 40001-3, OPC 40001-3 Machinery Job Mgmt – V1.0.1

https://opcfoundation.org/documents/40001-3/

3 Terms, definitions and conventions

3.1 Overview

It is assumed that basic concepts of OPC UA information modelling are understood in this specification. This specification will use these concepts to describe the Woodworking Information Model. For the purposes of this document, the terms and definitions given in OPC 10000-1, OPC 10000-3, OPC 10000-4, OPC 10000-5, OPC 10000-7, OPC 10000-100, OPC 40001-1 and OPC 40001-3 as well as the following apply.

Note that OPC UA terms and terms defined in this specification are italicized in the specification.

3.2 OPC UA for Woodworking terms

3.2.1 Untitled

Automatic mode

operational mode in which the machine operates in automatically without operator commands.

3.2.2 Untitled

Axis

mechanical joint of a manipulator that performs a linear or a rotational movement

3.2.3 Untitled

Maintenance

action for the achievement of machine-preserving measures

3.2.4 Untitled

Manual activity

activity to be performed manually by the operator

3.2.5 Untitled

Operator

person designated to start, monitor and stop the intended operation of a machine.

3.2.6 Untitled

Run

the single, complete execution of a recipe

3.2.7 Untitled

Tool

exchangeable components used in a machine to execute the production process

Note: They may for example be drills, ball milling heads, cutting inserts, pinching tools and so forth. May be a non-contact tool, for example a processing laser.

3.2.8 Untitled

Tool change

Tool change in context of this interface is the action of inserting a tool into the machine. There are two reasons this is done or necessary: 1) tool life of one group of tools has expired and machining cannot continue until a new tool with sufficient tool life for the next operation is inserted (causing a tool change) 2) a tool for a given job is not available (or defined as "hand tool" and) must be provided.

3.3 Abbreviated terms

3.4 Conventions used in this document

3.4.1 Conventions for Node descriptions

3.4.1.1 Node definitions

Node definitions are specified using tables (see Table 2).

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.

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. Examples are given in Table 1.

The TypeDefinition is specified for Objects and Variables.

The TypeDefinition column specifies a symbolic name for a NodeId, i.e. the specified Node points with a HasTypeDefinition Reference to the corresponding Node.

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

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

Note that if a symbolic name of a different namespace is used, it is prefixed by the NamespaceIndex (see 3.4.2.2).

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 part of this document points to their definition. Table 2 illustrates the table. If no components are provided, the DataType, TypeDefinition and ModellingRule columns may be omitted and only a Comment column is introduced to point to the Node definition.

Each Type Node or well-known Instance Node defined shall have one or more ConformanceUnits defined in 8.1 that require the Node to be in the AddressSpace.

The relations between Nodes and ConformanceUnits are defined at the end of the tables defining Nodes, one row per ConformanceUnit. The ConformanceUnits are reflected in the Category element for the Node definition in the UANodeSet (see OPC 10000-6).

The list of ConformanceUnits in the UANodeSet allows Servers to optimize resource consumption by using a list of supported ConformanceUnits to select a subset of the Nodes in an Information Model.

When a Node is selected in this way, all dependencies implied by the References are also selected.

Dependencies exist if the Node is the source of HasTypeDefinition, HasInterface, HasAddIn or any HierarchicalReference. Dependencies also exist if the Node is the target of a HasSubtype Reference. For Variables and VariableTypes, the value of the DataType Attribute is a dependency. For DataType Nodes, any DataTypes referenced in the DataTypeDefinition Attribute are also dependencies.

For additional details see OPC 10000-5.

Components of Nodes can be complex that is containing components by themselves. The TypeDefinition, NodeClass and DataType can be derived from the type definitions, and the symbolic name can be created as defined in 3.4.3.1. Therefore, those containing components are not explicitly specified; they are implicitly specified by the type definitions.

The Other column defines additional characteristics of the Node. Examples of characteristics that can appear in this column are show in Table 3.

If multiple characteristics are defined, they are separated by commas. The name or the short name may be used.

3.4.1.2 Additional References

To provide information about additional References, the format as shown in Table 4 is used.

References can be to any other Node.

3.4.1.3 Additional sub-components

To provide information about sub-components, the format as shown in Table 5 is used.

3.4.1.4 Additional Attribute values

The type definition table provides columns to specify the values for required Node Attributes for InstanceDeclarations. To provide information about additional Attributes, the format as shown in Table 6 is used.

There can be multiple columns to define more than one Attribute.

3.4.2 NodeIds and BrowseNames

3.4.2.1 NodeIds

The NodeIds of all Nodes described in this standard 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 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 NamespaceUri for all NodeIds defined in this document is defined in Annex A. The NamespaceIndex for this NamespaceUri is vendor-specific and depends on the position of the NamespaceUri in the server namespace table.

Note that this document not only defines concrete Nodes, but also requires that some Nodes shall be generated, for example one for each Session running on the Server. 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 in this document, because they are not defined by this document but generated by the Server.

3.4.2.2 BrowseNames

The text part of the BrowseNames for all Nodes defined in this document is specified in the tables defining the Nodes. The NamespaceUri for all BrowseNames defined in this document is defined in 9.2.

For InstanceDeclarations of NodeClass Object and Variable that are placeholders (OptionalPlaceholder and MandatoryPlaceholder ModellingRule), the BrowseName and the DisplayName are enclosed in angle brackets (<>) as recommended in OPC 10000-3.

If the BrowseName is not defined by this document, a namespace index prefix is added to the BrowseName (e.g., prefix '0' leading to ‘0:EngineeringUnits’ or prefix '2' leading to ‘2:DeviceRevision’). This is typically necessary if a Property of another specification is overwritten or used in the OPC UA types defined in this document. Table 53 provides a list of namespaces and their indexes as used in this document.

3.4.3 Common Attributes

3.4.3.1 General

The Attributes of Nodes, their DataTypes and descriptions are defined in OPC 10000-3. Attributes not marked as optional are mandatory and shall be provided by a Server. The following tables define if the Attribute value is defined by this specification or if it is server-specific.

For all Nodes specified in this specification, the Attributes named in Table 7 shall be set as specified in the table.

3.4.3.2 Objects

For all Objects specified in this specification, the Attributes named in Table 8 shall be set as specified in the table. The definitions for the Attributes can be found in OPC 10000-3.

3.4.3.3 Variables

For all Variables specified in this specification, the Attributes named in Table 9 shall be set as specified in the table. The definitions for the Attributes can be found in OPC 10000-3.

3.4.3.4 VariableTypes

For all VariableTypes specified in this specification, the Attributes named in Table 10 shall be set as specified in the table. The definitions for the Attributes can be found in OPC 10000-3.

3.4.3.5 Methods

For all Methods specified in this specification, the Attributes named in Table 11 shall be set as specified in the table. The definitions for the Attributes can be found in OPC 10000-3.

3.4.4 Structures

OPC 10000-3 differentiates between different kinds of Structures. The following conventions explain, how these Structures shall be defined.

The first kind are Structures without optional fields where none of the fields allows subtype (except fields with abstract DataTypes). Its definition is in Table 12.

The second kind are Structures with optional fields where none of the fields allows subtypes (except fields with abstract DataTypes). Its definition is in Table 13.

Structures with fields that are optional have an “Optional” column. Fields that are optional have true set, otherwise False.

The third kind are Structures without optional fields where one or more of the fields allow subtypes. Its definition is in Table 14.

Structures with fields that allow subtypes have an “Allow Subtypes” column. Fields that allow subtypes have true set, otherwise False. Fields with abstract DataTypes can always be subtyped.

4 General information to Woodworking and OPC UA

4.1 Introduction to Woodworking

EUMABOIS is the pan European industrial federation grouping 13 national associations which represent the major European manufacturers of machines, plants, tooling and ancillary equipment for the forestry and woodworking industries.

Encompassing some 850 industrial companies with a total turnover of 6 billion euro. The European industry can count on a work force of more than 35,000 employees. EUMABOIS members produce specialized machinery, cutting tools and auxiliary equipment for the forestry and primary timber processing sectors, incorporating plants for sawing, drying, veneer production, plywood and all timber-based boards and panels, e.g. chipboard, MDF, OSB, LVL panels.

EUMABOIS members manufacture standard and specialized machinery, plants and tooling for secondary processing for the production of all types of solid wood and panel products including furniture, chair frames, doors and windows.

Members also design, build and supply state of the art numerical control systems, sensors for robots and flexible manufacturing systems (FMS). Technologies that facilitate environmental protection and occupational safety within the woodworking industry and a comprehensive range of services complete the unique offer of the European manufacturers.

The mission of EUMABOIS is to facilitate a business environment (legislation, innovation, technology, environment, skilled workforce, financing, supply chain and infrastructure) to market the most competitive manufacturing solutions worldwide.

4.2 Introduction to OPC Unified Architecture

4.2.1 What is OPC UA?

OPC UA is an open and royalty free set of standards designed as a universal communication protocol. While there are numerous communication solutions available, OPC UA has key advantages:

A state of art security model (see OPC 10000-2).

A fault tolerant communication protocol.

An information modelling framework that allows application developers to represent their data in a way that makes sense to them.

OPC UA has a broad scope which delivers for economies of scale for application developers. This means that a larger number of high-quality applications at a reasonable cost are available. When combined with semantic models such as Woodworking, OPC UA makes it easier for end users to access data via generic commercial applications.

The OPC UA model is scalable from small devices to ERP systems. OPC UA Servers process information locally and then provide that data in a consistent format to any application requesting data - ERP, MES, PMS, Maintenance Systems, HMI, Smartphone or a standard Browser, for examples. For a more complete overview see OPC 10000-1.

4.2.2 Basics of OPC UA

As an open standard, OPC UA is based on standard internet technologies, like TCP/IP, HTTP, Web Sockets.

As an extensible standard, OPC UA provides a set of Services (see OPC 10000-4) and a basic information model framework. This framework provides an easy manner for creating and exposing vendor defined information in a standard way. More importantly all OPC UA Clients are expected to be able to discover and use vendor-defined information. This means OPC UA users can benefit from the economies of scale that come with generic visualization and historian applications. This specification is an example of an OPC UA Information Model designed to meet the needs of developers and users.

OPC UA Clients can be any consumer of data from another device on the network to browser based thin clients and ERP systems. The full scope of OPC UA applications is shown in Figure 1.

OPC UA provides a robust and reliable communication infrastructure having mechanisms for handling lost messages, failover, heartbeat, etc. With its binary encoded data, it offers a high-performing data exchange solution. Security is built into OPC UA as security requirements become more and more important especially since environments are connected to the office network or the internet and attackers are starting to focus on automation systems.

4.2.3 Information modelling in OPC UA

4.2.3.1 Concepts

OPC UA provides a framework that can be used to represent complex information as Objects in an AddressSpace which can be accessed with standard services. These Objects consist of Nodes connected by References. Different classes of Nodes convey different semantics. For example, a Variable Node represents a value that can be read or written. The Variable Node has an associated DataType that can define the actual value, such as a string, float, structure etc. It can also describe the Variable value as a variant. A Method Node represents a function that can be called. Every Node has a number of Attributes including a unique identifier called a NodeId and non-localized name called as BrowseName. An Object representing a ‘Reservation’ is shown in Figure 2.

Object and Variable Nodes represent instances and they always reference a TypeDefinition (ObjectType or VariableType) Node which describes their semantics and structure. Figure 3 illustrates the relationship between an instance and its TypeDefinition.

The type Nodes are templates that define all of the children that can be present in an instance of the type. In the example in Figure 3 the PersonType ObjectType defines two children: First Name and Last Name. All instances of PersonType are expected to have the same children with the same BrowseNames. Within a type the BrowseNames uniquely identify the children. This means Client applications can be designed to search for children based on the BrowseNames from the type instead of NodeIds. This eliminates the need for manual reconfiguration of systems if a Client uses types that multiple Servers implement.

OPC UA also supports the concept of sub-typing. This allows a modeller to take an existing type and extend it. There are rules regarding sub-typing defined in OPC 10000-3, but in general they allow the extension of a given type or the restriction of a DataType. For example, the modeller may decide that the existing ObjectType in some cases needs an additional Variable. The modeller can create a subtype of the ObjectType and add the Variable. A Client that is expecting the parent type can treat the new type as if it was of the parent type. Regarding DataTypes, subtypes can only restrict. If a Variable is defined to have a numeric value, a sub type could restrict it to a float.

References allow Nodes to be connected in ways that describe their relationships. All References have a ReferenceType that specifies the semantics of the relationship. References can be hierarchical or non-hierarchical. Hierarchical references are used to create the structure of Objects and Variables. Non-hierarchical are used to create arbitrary associations. Applications can define their own ReferenceType by creating subtypes of an existing ReferenceType. Subtypes inherit the semantics of the parent but may add additional restrictions. Figure 4 depicts several References, connecting different Objects.

The figures above use a notation that was developed for the OPC UA specification. The notation is summarized in Figure 5. UML representations can also be used; however, the OPC UA notation is less ambiguous because there is a direct mapping from the elements in the figures to Nodes in the AddressSpace of an OPC UA Server.

A complete description of the different types of Nodes and References can be found in OPC 10000-3 and the base structure is described in OPC 10000-5.

OPC UA specification defines a very wide range of functionality in its basic information model. It is not required that all Clients or Servers support all functionality in the OPC UA specifications. OPC UA includes the concept of Profiles, which segment the functionality into testable certifiable units. This allows the definition of functional subsets (that are expected to be implemented) within a companion specification. The Profiles do not restrict functionality, but generate requirements for a minimum set of functionality (see OPC 10000-7).

4.2.3.2 Namespaces

OPC UA allows information from many different sources to be combined into a single coherent AddressSpace. Namespaces are used to make this possible by eliminating naming and id conflicts between information from different sources. Each namespace in OPC UA has a globally unique string called a NamespaceUri which identifies a naming authority and a locally unique integer called a NamespaceIndex, which is an index into the Server's table of NamespaceUris. The NamespaceIndex is unique only within the context of a Session between an OPC UA Client and an OPC UA Server- the NamespaceIndex can change between Sessions and still identify the same item even though the NamespaceUri's location in the table has changed. The Services defined for OPC UA use the NamespaceIndex to specify the Namespace for qualified values.

There are two types of structured values in OPC UA that are qualified with NamespaceIndexes: NodeIds and QualifiedNames. NodeIds are locally unique (and sometimes globally unique) identifiers for Nodes. The same globally unique NodeId can be used as the identifier in a node in many Servers – the node's instance data may vary but its semantic meaning is the same regardless of the Server it appears in. This means Clients can have built-in knowledge of what the data means in these Nodes. OPC UA Information Models generally define globally unique NodeIds for the TypeDefinitions defined by the Information Model.

QualifiedNames are non-localized names qualified with a Namespace. They are used for the BrowseNames of Nodes and allow the same names to be used by different information models without conflict. TypeDefinitions are not allowed to have children with duplicate BrowseNames; however, instances do not have that restriction.

4.2.3.3 Companion Specifications

An OPC UA companion specification for an industry specific vertical market describes an Information Model by defining ObjectTypes, VariableTypes, DataTypes and ReferenceTypes that represent the concepts used in the vertical market, and potentially also well-defined Objects as entry points into the AddressSpace.

5 Use cases

5.1 Use case 1: Identification of Machines of different Manufacturers

The machines of different manufacturers shall be identifiable in a standardized manner. To realize this, a number of basic and static information like manufacturer name and model number are offered on the interface.

Links to related chapters:

7.1 Finding Woodworking Machines in a Server

7.2 WwMachineType ObjectType Definition

5.2 Use case 2: Overview of Machine States

The machines of different manufacturers offer their states in a standardized manner.

Links to related chapters:

7.3 IWwStateType InterfaceType Definition

7.4 IWwSubUnitsType InterfaceType Definition

7.5 IWwBaseStateType InterfaceType Definition

7.6 IWwUnitOverviewType InterfaceType Definition

7.7 WwUnitStateEnumeration

7.8 WwUnitModeEnumeration

7.9 IWwUnitFlagsType InterfaceType Definition

5.3 Use case 3: Overview of Machine Messages

The machine is expected to offer all current messages such as alarms, warnings and information over the interface. These errors and warnings shall be mapped to OPC UA event types accordingly.

Links to related chapters:

7.11 IWwEventMessageType InterfaceType Definition

7.12 WwEventCategoryEnumeration

7.13 WwMessageArgumentDataType

7.14 WwMessageArgumentValueDataType

7.15 WwBaseEventType ObjectType Definition

7.16 WwConditionType ObjectType Definition

7.17 WwAcknowledgeableConditionType ObjectType Definition

7.18 WwAlarmConditionType ObjectType Definition

7.19 WwEventsDispatcherType ObjectType

5.4 Use case 4: Providing Information for KPI calculations

To facilitate the calculation of different KPIs like for example OEE, the interface offers different item values with their changing times. These times allow to calculate the durations of different machine modes.

All of these relevant times are transferred with OPC UA mechanisms. Each state change is sent to the OPC UA Client, and the timestamp can be used to calculate the time durations needed for KPI compilation.

Link to related chapter:

7.10 IWwUnitValuesType InterfaceType Definition

5.5 Use case 5: Overview of Runtimes for a Job

In order to calculate cycle times and prognoses for production by an external system, the interface provides the time data of start, end, interruption and abortion of machining processes and programs on the machine.

Link to related chapter:

7.20 Job-Order-Input and Job-Order-Response Information

5.6 Use case 6: Overview of the Workpiece in a Job

Using the interface, an overview of the target and actual manufactured parts is possible. Additionally, it is possible to see which workpiece belong to which internal or customer order. If there is an irregularity in the process, which might affect the workpiece quality, the workpiece representation on the interface can be marked accordingly.

Link to related chapter:

7.20 Job-Order-Input and Job-Order-Response Information

5.7 Use case 7: Job Handling

A production manager wants to transfer and handle all necessary job data for a machine, i.e. transfer, modify, delete etc.

Link to related chapter:

7.20 Job-Order-Input and Job-Order-Response Information

5.8 Use case 8: Provide OPC UA for Machinery Use Cases

The Woodworking interface makes use of OPC 40001-1. It provides the MachineryBuildingBlocks folder, directly referencing all Machinery Building Blocks used by the Woodworking interface instance. In addition, the Woodworking interface incorporates OPC 40001-3. This specification provides the use cases for job management.

Link to related chapter:

7.2 WwMachineType ObjectType Definition

6 Woodworking Information Model overview

7 OPC UA Types and Interfaces

7.1 Finding Woodworking Machines in a Server

All instances of WwMachineType in a Server shall be referenced from the 3:Machines Object as defined in OPC 40001-1. This provides the capability to easily find all woodworking machines managed in a Server. The 3:Machines Object may contain other Nodes than instances of WwMachineType.

Each <Machine> Object represents an instance of a machine. In the simplest case, there is only one machine. The BrowseName of <Machine> should be unique within the Server. For woodworking machines it could be the 2:ProductInstanceUri of the 2:Identification Object of the 2:IVendorNameplateType.

7.2 WwMachineType ObjectType Definition