1 Scope

This document provides information-modelling concepts and object libraries that can be applied to model a complete production workcentre or line. It covers machine configurations, product flows, production, set-up, service, live status as well as historical information. It applies to primary and secondary production, including conventional and heat-not-burn products.

This document aims at harmonizing data exchange and interoperability requirements for the common benefit of both cigarette manufacturers and OEMs.

OPC Foundation

OPC is the interoperability standard for the secure and reliable exchange of data and information in the industrial automation space and in other industries. It is platform independent and ensures the seamless flow of information among devices from multiple vendors. The OPC Foundation is responsible for the development and maintenance of this standard.

OPC UA is a platform independent service-oriented architecture that integrates all the functionality of the individual OPC Classic specifications into one extensible framework. This multi-layered approach accomplishes the original design specification goals of:

Platform independence: from an embedded microcontroller to cloud-based infrastructure

Secure: encryption, authentication, authorization and auditing

Extensible: ability to add new features including transports without affecting existing applications

Comprehensive information modelling capabilities: for defining any model from simple to complex

TMC Working Group

The Tobacco Machine Communication (TMC) Working Group was formed to help secondary machine manufacturers design their machines to meet the harmonised requirements of its clients, both in terms of machine-to-machine communication and in terms of machine-to-manufacturing system communication.

At the time of writing the TMC Working Group consists of the following members:

British American Tobacco

Imperial Tobacco Group

JT International

Philip Morris International

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.

For OPC UA referenced documents, 1.04.7 is the minimum required version for the following OPC Unified Architecture parts.

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

OPC 10000-100, OPC Unified Architecture - Part 100: Devices

OPC 10000-100

OPC 30050, OPC Unified Architecture – Common Object Model: PackML

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

3 Terms, abbreviated terms and conventions

3.1 Overview

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 Tobacco Machine Communication 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 10000-8, OPC 10000-16, OPC 10000-100, OPC 30050, as well as the following apply.

Additionally, the terms and definitions given in ISA 95 and ISA 88 apply.

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

3.2 OPC UA for Tobacco Machine Communication terms

3.2.1 Untitled

A mechanical artifact that performs one or more elementary process steps in processing tobacco or manufacturing cigarettes, e.g. hopper, rod maker, etc.

3.2.2 Untitled

A set of machine modules connected to each other so that the finished product can be progressively assembled while materials flow through.

3.2.3 Untitled

An organisation that runs one or more workcentres to produce cigarettes.

3.2.4 Untitled

Original Equipment Manufacturer: a manufacturer of machine modules.

3.2.5 Untitled

A period of time when a Machine Module is not available for production, e.g. because of a malfunction.

3.2.6 Untitled

A message that is reported by the control system of a machine module when a malfunction occurs.

3.2.7 Untitled

The root cause that caused a malfunction and the consequent downtime.

3.2.8 Untitled

An automatic mode of operation for a machine module that reduces the energy consumption.

3.2.9 Untitled

A token of information that affects the operation of a machine module.

3.2.10 Untitled

The process that verifies that a machine module can operate under a certain set of parameters.

3.2.11 Untitled

The system that the OPC UA Server is interfacing to higher-level systems like SCADA, MES.

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 Other columns may be omitted and only a Comment column is introduced to point to the Node definition.

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 14.2.

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 260 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 document or if it is server-specific.

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

3.4.3.3 Variables

For all Variables specified in this document, 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 document, 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 document, 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.

The implementation of methods shall be such that, if the execution fails, the state of the underlying system will be rolled back to what it was before the execution of the method started. In other words, no partial execution is allowed for methods.

3.4.4 Conventions for Tobacco Machine Communication

3.4.4.1 Types and Instances

Instances of a type <Some>Type will be simply called <Some> singular or <Some>s plural according to the need. Please, note the Italic.

This short-hand form makes the text more readable while preserving disambiguation, as one can simply add the suffix Type to identify the type as defined in the present document.

For example, MachineModules identify instances of type MachineModuleType, MaterialLoadingPoints are instances of type MaterialLoadingPointType and so on and so forth.

4 General information to Tobacco Machine Communication and OPC UA

4.1 Introduction to Tobacco Machine Communication

In most tobacco factories the machine communication landscape, both in primary and in secondary, is highly fragmented, both for machine-to-machine and machine-to-higher systems data streams.

The fragmentation is evident on many levels: physical media, protocols, data formats, sometimes proprietary, have added up over time with the machines. Unnecessarily high integration efforts result.

Moreover, extracting manufacturing insights from the machine data is a valuable opportunity that is severely limited by the fragmentation.

The Tobacco Machine Communication specification aims at harmonizing data exchange and interoperability requirements for the common benefit of both tobacco manufacturers and OEMs.

The Tobacco Machine Communication specification provides information-modelling concepts and object libraries that can be applied to model a complete production workcentre or line. It covers machine configurations, product flows, production, set-up, service, live status as well as historical information. Its scope encompasses both primary and secondary production, including conventional and heat-not-born products.

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 the Tobacco Machine Communication, 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 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

This OPC UA companion specification provides support for multiple use cases connected to production machines running both in primary and secondary. Key use cases follow below:

Manage machine’s Overall Equipment Effectiveness, including identifying downtime and its root causes both for machines and for complex lines where it is important to identify which machine is the root cause. To this end, TMC uses TMCStateMachineType, an enhanced PackML state machine, stop reasons and root causes for downtime.

Manage production yield, meaning that high-quality machine or line output data is provided altogether with consumption and dispensing information on the input end and material waste and rejections to compute the line mass balance.
To this end, TMC has its backbone in MaterialLoadingPointType, MaterialOutputPointType and MaterialRejectionPointType.

Manage defects, identifying material rejections and their causes, including defect detections and the root cause reasons for detections. To this end, TMC provides a multi-layered model consisting of DefectDetectionSensorType, SensorFunctionType and DefectReasonType.

Enforce MES-integrated production orders for workcentres, including the dispatching of recipe datasets and material lists, which are constantly monitored during execution for changes and material integrity. To this end, TMC provides core constructs such as DatasetType, MaterialListType and ProductionOrderType.

Enforce MES-integrated production orders for process cells, including the orderly execution of a production order among workcentres (units) connected in any non-loopy process cell layout. To this end, TMC provides the ProductionOrderOrchestrationLayerType, as well as MachineModuleProductionStateMachineType to enforce and monitor execution.

Feed a companywide IIoT data stack, including pervasive, structured, high-quality data collection with aggregation directly at the data source for fast changing signals. To this end ProcessItemType is the core construct in conjunction with multiple pre-defined data points for machine, production data and events.

Implement remote control loops, meaning external smart applications, e.g. AI powered, can increase the production quality by controlling remotely existing machines. To this end, TMC provides ProcessControlLoopType with the necessary watchdogs and remote alarming.

Connect centralised SCADA systems above the machine HMI, including visualization and control functionality in a standardised and uniform way according to the ISA 88 physical structure model. To this end, TMC provides EquipmentModuleType, ControlModuleType with the relevant status and alarming functions.

Support smart visualisation applications above the machine HMI, including visualization resources so that a smart visualisation system can programmatically build visualisation and control functions. To this end, TMC provides the UIInformationType.

6 Tobacco Machine Communication Information Model overview

The main construct is the MachineModuleType ObjectType which is derived from an OPC 10000-100 DeviceType containing additional Information, including MachineModuleHistoricalRecord (8.2), MachineModuleConfiguration (8.3), MachineModuleLiveStatus (8.4), MachineModuleProduction (8.5), MachineModuleSpecification (8.6) and MachineModuleSetup (8.7).

MachineModules describe the production flow by means of their MaterialLoadingPoints (8.8), MaterialOutputPoints (8.9), MaterialStorageBuffers (8.10) where product is stored during production and MaterialRejectionPoints (8.11). MaterialRejectionPoints are triggered by DefectDetectionSensors (8.12) which contain SensorFunctions (8.13) and DefectReasons (8.14).

Connecting the MaterialOutputPoints of MachineModules to the MaterialLoadingPoints of the downstream MachineModule provides the production graph.

As far as production is concerned, a MachineModule is functionally equivalent to a Unit in ISA 95/88 language. A collection of MachineModules and their production graph make a Process Cell as defined in ISA 95/88.

Production in a non-loopy Process Cell, i.e. no connections looping back in the production graph, is orchestrated by means of the ProductionOrderOrchestrationLayer (8.38).

A MachineModule may contain one or more EquipmentModules (8.15) or ControlModules (8.19). In turn EquipmentModules may contain one or more ControlModules. Typical ControlModules such as AnalogInputs (8.25), DigitalInputs (8.26), Motors (8.27), Sensors (8.28) and Valves (8.29) are also provided.

Most TMC objects are described by a suitable state machine, TMCMachineStateMachine (8.43) and production state machines (8.39 and 8.40), that inherit from the OMAC PackML standardization effort adding guards to the transitions.

ProcessControlLoops (8.46) may also be included in MachineModules or used alone to expose a control loop in control of the underlying system or remotely controlled.

7 TMC Guideline

7.1 Naming Convention

One of the key goals of OPC UA is to communicate information, not just data. In order to do so, it is important that meaningful metadata is attached, starting with object names.

The names of objects are intended to tell objects apart and straightforwardly clarify what the object is, i.e. they must be human readable avoiding serials, UIDs, uncommon acronyms and other prefixes and suffixes that limit the human understanding whenever possible.

Developers shall name objects according to the following rules and principles:

CamelCase: the CamelCase capitalisation practice will be used for all names. Moreover, the developer shall comply with the whitepaper OPC11030 UA Modeling Best Practices.

Names shall be unique at their hierarchy level: no two servers provided by the same OEM shall have the same name twice, no two machine modules in the same server shall have the same name twice, no two loading points in the same machine module will have the same name twice and so on.

For instance, applying the principles above, it is acceptable to name a server adding a suffix to the machine name with a machine serial or UID e.g. Maker123, Maker 456 because no other alternative ensuring uniqueness is given. Prefixing makes the name less readable and shall be avoided.

Like function, like name: functionally equivalent objects will carry the same name. For example, each instance of a paper loading point in different machine modules will be named PaperLoadingPoint.

If a machine contains multiple objects with the same name, then the name will be completed with a suffix that allows to distinguish the objects with the same function. To continue the previous example, PaperLoadingPoint1 and PaperLoadingPoint2 are acceptable. Please, note that two paper loading points, for tipping paper and cigarette paper, will not be specialised by a suffix but a functional prefix is required i.e. TippingPaperLoadingPoint, CigarettePaperLoadingPoint because their function is different.

Name for brevity: names shall not contain redundant information and in particular information that is carried by the name of a parent object. Thus the name of a component of the SomeMachineModule shall not contain SomeMachineModule or any other string (serial, UID or similar) identifying the machine module, because the information is already captured by the name of the parent object given the inherently hierarchical structure of the TMC nodeset.

The description property and display name that belong to each object/variable instance contained in a TMC server will provide a short phrase in plain English that explains what the instance is and that an average user familiar with the domain can understand.

7.2 Historization and Persistency

The value of Nodes with readable history (marked as HR in the Other column) shall be persisted for a period of 8 hours, meaning the last 8 (eight) hours of data will be available.

The server shall implement historization of events for all events, accessible by client via the OPC UA service history read. The historization internal storage shall be sized to persist at least 1 (one) hour of events generated at the average server generation rate.

The Value of Nodes with NodeClass Variable shall be persisted in the control system in such a way that, in case of a hardware failure or replacement, the TMC server values will not be reset.

7.3 NodeIds

Nodes are unambiguously identified using a constructed identifier called the NodeId. A Server shall persist the NodeId of a Node, that is, it shall not generate new NodeIds when rebooting. In case of an update, a Server shall not generate new NodeIds for Nodes that have not been added with the update.

8 OPC UA ObjectTypes

8.1 MachineModuleType ObjectType

8.1.1 Overview