It is assumed that basic concepts of OPC UA information modelling are understood in this document. This document will use these concepts to describe the Machine Tools 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 10000-9, OPC 10000-100, OPC 10000-200, OPC 40001-1as well as the following apply.

Note that OPC UA terms and terms defined in this document are italicisedin the document.

defined message indicating noteworthy information for the operator and for historic dataAn alert can have three subcategories: Error - indicating a state that blocks operation of the process.Warning - indicating a state that requires attention, it can prevent operation in indicated way, however it is generally not blocking operation of the process.Message - display of information the machine tool builder deemed necessary to display, neither blocking or reducing operational capability.

runtime component of the CNC which executes an NC programThis execution may happen in Block Sequence mode (execution of the next NC command starts as soon as the previous has completed), or Single Block Mode (NC channels stops and waits for a NC Start signal to resume executing the next NC program block). A channel contains an assigned set of axes which can be moved in a synchronised interpolated manner. Auxiliary axes may also be assigned to a channel which will usually be commanded in a synchronized uninterpolated manner. An active NC channel runs current NC programs which relate to the workpiece etc. Depending on the machine there may be several active NC channels running simultaneously.

hybrid hardware/software systems that are used for controlling machines

EXAMPLE: Distributed control systems (DCS), programmable logic controllers (PLC), numerical controller (NC), and supervisory control and data acquisition (SCADA) systems.

[SOURCE: ISO 16100-1:2009, 3.7]

mechanical device which is fixed (i.e. not mobile) and powered (typically by electricity and compressed air), typically used to process workpieces by selective removal/addition of material or mechanical deformation

[SOURCE: ISO 14955-1:2017, 3.16, modified: Note to entry deleted]

manual action of inserting a tool into the machine as opposed to an Automatic Tool ChangeThere are two common 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" meaning it needs to be inserted/changed manually at the time it is needed) and shall be provisioned.

unit of different tools, usually used in order to have several tools available in-process without requiring explicit tool-changesTypical applications are in turning, when one indexed position of the tool revolver holds several outer-diameter cutting inserts and boring tools, such that a tool change process can quickly complete by merely readjusting the CNC setpoint position for the tool compensation.

workpiece of the machine which is worked on with the machine’s technologyThis may be for the purpose of machining, measuring or others, depending on the machine type.

list of all job elements a specific machine knows aboutEXAMPLE: All jobs which were transferred to the machine in some way.

also: production job; concrete implementation of one or more programs or recipes by means of a given orderprovides one to many production programs and the instruction to produce one to many parts; offers the possibility to aggregate the manufacturing of multiple parts or the manufacturing of a part through multiple programs

also: production program; list of operations that the controller performs in sequence;usually a machine-readable file, such as an NC program, which is needed for the controller to fulfil the job; NC programs may also carry a hierarchy of further sub-(NC)programs

tool with equivalent (identical) process capabilities (size and functionality) to an existing tool; used by the controller if the designated tool is locked due to wear, done automatically and/or after user interaction

visual machine state indicator; consists of one or more lamps stacked on top of one another, each having a specific, in most cases different colourThe combination of on/off/blinking lights in the stacklight corresponds to a machine state. The ordering of the colours is counted from the base of the stacklight unit.

exchangeable component used in a machine tool to execute the machining processEXAMPLE: May be drills, ball milling heads, cutting inserts, pinching tools and so forth, or even a non-contact tool like a processing laser.

umbrella term for all media (pressurized air, coolant, lubrication, etc.) and consumables (filters, space in chip carts, etc.) necessary for running the machine.Tools as consumables are excluded from this definition as tools are in their own class of complexity and therefore defined separately.

CNCComputerized Numerical Control

EDMElectrical Discharge Machining

ERPEnterprise Resource Planning

HMIHuman Machine Interface

KPIKey Performance Indicator

MESManufacturing Execution System

MOMode of Operation

NCNumerical Control

OEEOverall Equipment Effectiveness

SCADASupervisory Control and Data Acquisition

VDWVerein Deutscher Werkzeugmaschinenfabriken e.V. (German Machine Tool Builders’ Association)

Nodedefinitions are specified using tables (see Table 2).

Attributesare defined by providing the Attributename and a value, or a description of the value.

Referencesare defined by providing the ReferenceTypename, the BrowseNameof the TargetNodeand its NodeClass.

  • If the TargetNodeis a component of the Nodebeing defined in the table the Attributesof the composed Nodeare defined in the same row of the table.
  • The DataTypeis 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 ArrayDimensionsis 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 ArrayDimensionscan be omitted. If no brackets are provided, it identifies a scalar DataTypeand the ValueRankis set to the corresponding value (see OPC 10000-3). In addition, ArrayDimensionsis 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 ValueRankis set to the corresponding value (see OPC 10000-3) and the ArrayDimensionsis set to null or is omitted. Examples are given in Table 1.

Table 1– Examples of DataTypes









omitted or null

A scalar Int32.




omitted or {0}

Single-dimensional array of Int32 with an unknown size.




omitted or {0,0}

Two-dimensional array of Int32 with unknown sizes for both dimensions.





Two-dimensional array of Int32 with a size of 3 for the first dimension and an unknown size for the second dimension.





Two-dimensional array of Int32 with a size of 5 for the first dimension and a size of 3 for the second dimension.




omitted or null

An Int32 where it is unknown if it is scalar or array with any number of dimensions.




omitted or null

An Int32 where it is either a single-dimensional array or a scalar.

If the NodeIdof a DataTypeis provided, the symbolic name of the Noderepresenting the DataTypeshall be used.

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

Nodesof all other NodeClassescannot be defined in the same table; therefore, only the used ReferenceType, their NodeClassand their BrowseNameare specified. A reference to another part of this document points to their definition.

Table 2illustrates the table. 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 Nodedefinition.

Table 2– Type Definition Table



Attribute name

Attribute value. If it is an optional Attribute that is not set “--“ is used.








NodeClassof the TargetNode.

BrowseNameof the target Node. If the Referenceis to be instantiated by the server, then the value of the target Node’s BrowseName is “--“.

DataType of the referenced Node, only applicable for Variables.

TypeDefinitionof the referenced Node, only applicable for Variablesand Objects.

Additional characteristics of the TargetNodesuch as the ModellingRuleor AccessLevel.

NOTE Notes referencing footnotes of the table content.

Components of Nodescan be complex that is containing components by themselves. The TypeDefinition, NodeClassand DataType can be derived from the type definitions, and the symbolic name can be created as defined in 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.

Table 3– Examples of Other Characteristics


Short Name




The Nodehas the Mandatory ModellingRule.



The Nodehas the Optional ModellingRule.



The Nodehas the MandatoryPlaceholder ModellingRule.



The Nodehas the OptionalPlaceholder ModellingRule.



The Node AccessLevelhas the CurrentReadbit set but not the CurrentWritebit.



The Node AccessLevelhas the CurrentReadand CurrentWritebits set.



The Node AccessLevel has the CurrentWritebit set but not the CurrentReadbit.

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

The NodeIdsof all Nodesdescribed in this standard are only symbolic names. Annex Adefines the actual NodeIds.

The symbolic name of each Nodedefined in this document is its BrowseName, or, when it is part of another Node, the BrowseNameof the other Node, a “.”, and the BrowseNameof itself. In this case “part of” means that the whole has a HasPropertyor HasComponent Referenceto its part. Since all Nodesnot being part of another Nodehave a unique name in this document, the symbolic name is unique.

The NamespaceUrifor all NodeIdsdefined in this document is defined in Annex A. The NamespaceIndexfor this NamespaceUriis vendor-specific and depends on the position of the NamespaceUriin the server namespace table.

Note that this document not only defines concrete Nodes, but also requires that some Nodesshall be generated, for example one for each Sessionrunning on the Server. The NodeIdsof those Nodesare Server-specific, including the namespace. But the NamespaceIndexof those Nodescannot be the NamespaceIndexused for the Nodesdefined in this document, because they are not defined by this document but generated by the Server.

The text part of the BrowseNamesfor all Nodesdefined in this document is specified in the tables defining the Nodes. The NamespaceUrifor all BrowseNamesdefined in this document is defined in Annex A.

If the BrowseNameis not defined by this document, a namespace index prefix like ‘0:EngineeringUnits’ or ‘2:DeviceRevision’ is added to the BrowseName. This is typically necessary if a Propertyof another specification is overwritten or used in the OPC UA types defined in this document. Table 117provides a list of namespaces and their indexes as used in this document.

The Attributesof Nodes, their DataTypesand 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 Attributevalue is defined by this document or if it is server-specific.

For all Nodesspecified in this document, the Attributesnamed in Table 4shall be set as specified in the table.

Table 4– Common Node Attributes




The DisplayNameis a LocalizedText. Each server shall provide the DisplayNameidentical to the BrowseNameof the Nodefor the LocaleId“en”. Whether the server provides translated names for other LocaleIdsare server-specific.


Optionally a server-specific description is provided.


Shall reflect the NodeClassof the Node.


The NodeIdis described by BrowseNamesas defined in


Optionally the WriteMask Attributecan be provided. If the WriteMask Attributeis provided, it shall set all non-server-specific Attributesto not writable. For example, the Description Attributemay be set to writable since a Servermay provide a server-specific description for the Node. The NodeIdshall not be writable, because it is defined for each Nodein this document.


Optionally the UserWriteMask Attributecan be provided. The same rules as for the WriteMask Attributeapply.


Optionally server-specific role permissions can be provided.


Optionally the role permissions of the current Session can be provided. The value is server-specific and depends on the RolePermissions Attribute(if provided) and the current Session.


Optionally server-specific access restrictions can be provided.

For all Objectsspecified in this document, the Attributesnamed in Table 5shall be set as specified in the Table 5. The definitions for the Attributescan be found in OPC 10000-3.

Table 5– Common Object Attributes




Whether the Nodecan be used to subscribe to Eventsor not is server-specific.

For all Variablesspecified in this document, the Attributesnamed in Table 6shall be set as specified in the table. The definitions for the Attributescan be found in OPC 10000-3.

Table 6– Common Variable Attributes




Optionally, a server-specific minimum sampling interval is provided.


The access level for Variablesused for type definitions is server-specific, for all other Variablesdefined in this document, the access level shall allow reading; other settings are server-specific.


The value for the UserAccessLevel Attributeis server-specific. It is assumed that all Variablescan be accessed by at least one user.


For Variablesused as InstanceDeclarations,the value is server-specific; otherwise it shall represent the value described in the text.


If the ValueRankdoes not identify an array of a specific dimension (i.e. ValueRank<= 0) the ArrayDimensionscan either be set to null or the Attributeis missing. This behaviour is server-specific.

If the ValueRankspecifies an array of a specific dimension (i.e. ValueRank> 0) then the ArrayDimensions Attributeshall be specified in the table defining the Variable.


The value for the Historizing Attributeis server-specific.


If the AccessLevelEx Attributeis provided, it shall have the bits 8, 9, and 10 set to 0, meaning that read and write operations on an individual Variableare atomic, and arrays can be partly written.

For all VariableTypesspecified in this document, the Attributesnamed in Table 7shall be set as specified in the table. The definitions for the Attributescan be found in OPC 10000-3.

Table 7– Common VariableType Attributes




Optionally a server-specific default value can be provided.


If the ValueRankdoes not identify an array of a specific dimension (i.e. ValueRank<= 0) the ArrayDimensionscan either be set to null or the Attributeis missing. This behaviour is server-specific.

If the ValueRankspecifies an array of a specific dimension (i.e. ValueRank> 0) then the ArrayDimensions Attributeshall be specified in the table defining the VariableType.

For all Methodsspecified in this document, the Attributesnamed in Table 8shall be set as specified in the table. The definitions for the Attributescan be found in OPC 10000-3.

Table 8– Common Method Attributes




All Methodsdefined in this document shall be executable (Executable Attributeset to “True”), unless it is defined differently in the Methoddefinition.


The value of the UserExecutable Attributeis server-specific. It is assumed that all Methodscan be executed by at least one user.