1 Scope

This document specifies an OPC UA Information Model to create a device standard for analytical and laboratory instruments. This document provides a manufacturer-independent open standard, which comprehensively addresses the requirements of various branches, disciplines, and business processes, and is sustainable and adaptable to future requirements in the field of digitalization and automation.

This specification has been developed as a collaborative effort among OPC Foundation, Spectaris, and VDMA. More details on these organizations are provided below.

"Part 1: LADS Base System" is the first in a series of planned documents that will collectively form the Laboratory and Analytical Device Standard (LADS). While the exact structure and content of future parts are yet to be fully defined, they are anticipated to cover additional aspects of laboratory and analytical device standardization. Potential topics for future parts could include:

Dictionary References - This part would focus on referencing to dictionaries and ontologies (e.g., Allotrope Taxonomies Domain Model) so that the semantics of the OPC UA information are preserved throughout the data lifecycle and between the different levels.

Publish-Subscribe (PubSub) - This part would detail the use of the OPC UA PubSub communication model within the context of laboratory and analytical devices.

Alias Names - This part would establish standardized (handling of) alias names for common elements.

Samples and Consumables - This part would define how samples and consumables are represented and managed within the information model.

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.

SPECTARIS

SPECTARIS is the German industry association for the high-tech midsized business sector and a representative body in the areas of medical technology, consumer optics, analytical, bio and laboratory technology, as well as photonics. Innovation and growth characterize the different industry sectors and their 330,000-strong workforce. Technologies developed here are used in almost all branches of industry, making them an essential motor for the German economy.

SPECTARIS pools the interests of around 400 member companies from Germany, associated into four different sector-specific branches. Through its political activities, campaigns, services and technical support, the association helps its members in overcoming business barriers and opens up new markets.

Machinery and Equipment Manufacturers Association (VDMA)

The VDMA represents over 3,200 predominantly small and medium-sized member companies in the engineering industry, making it one of the largest and most important industrial associations in Europe. The VDMA covers the entire process chain of mechanical engineering - everything from components and plant manufacturers, system suppliers and system integrators through to service providers.

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

http://www.opcfoundation.org/documents/10000-1/

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

http://www.opcfoundation.org/documents/10000-2/

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

http://www.opcfoundation.org/documents/10000-3/

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

http://www.opcfoundation.org/documents/10000-4/

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

http://www.opcfoundation.org/documents/10000-5/

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

http://www.opcfoundation.org/documents/10000-6/

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

http://www.opcfoundation.org/documents/10000-7/

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

http://www.opcfoundation.org/documents/10000-8/

OPC 10000-16, OPC Unified Architecture - Part 16: State Machines

http://www.opcfoundation.org/documents/10000-16/

OPC 10000-19, OPC Unified Architecture - Part 19: Dictionary References

http://www.opcfoundation.org/documents/10000-19/

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

http://www.opcfoundation.org/documents/10000-100/

OPC 10000-110, OPC Unified Architecture - Part 110: Asset Management Basics

http://www.opcfoundation.org/documents/10000-110/

OPC 40001-1, OPC UA for Machinery - Part 1: Basic Building Blocks

http://www.opcfoundation.org/documents/40001-1/

3 Terms, abbreviations, and conventions

3.1 Overview

It is assumed that the basic concepts of OPC UA information modelling are understood in this document. This specification will use these concepts to describe the OPC UA LADS Information Model. For the purposes of this document, the terms and definitions given in OPC 10000-1, OPC 10000-2, OPC 10000-3, OPC 10000-4, OPC 10000-5, OPC 10000-6, OPC 10000-7, OPC 10000-8, OPC 10000-100, OPC 40001-1 as well as the following apply.

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

3.2 OPC UA LADS Terms

3.2.1 Device

Analytical or laboratory device, also known as an instrument.

3.2.2 Lab(oratory) Device

Instrument used in a laboratory to carry out specific tasks and generate the results of an analysis.

3.2.3 Analytical Device

Instrument to study scientific data and provide analytical results.

3.2.4 Component

Component of a device. (See OPC 10000-100.)

3.2.5 Remote

Non-local location in the lab network or the Internet.

3.2.6 Functional Unit

Aggregation of functions to achieve a specific outcome. (Typically utilized by only one user at a time, it exposes its current state via a state machine and might optionally include a Program Manager.)

3.2.7 Function

Action to achieve a specific outcome, organized by a Functional Unit. (Typical functions include but are not limited to sensors, controllers, actuators, timers, etc. They may utilize one or more tangible components.)

3.2.8 Program Manager

Organization of objects to manage program templates, run programs, and manage results.

3.2.9 Program Template

General configuration of settings or formats to be used as a basis for further definition of individual programs.

3.2.10 Actuator

Asset that causes a machine or other device to operate.

3.2.11 Controller

Asset that directs or regulates something.

3.2.12 Sensor

Asset that detects or measures a physical property.

3.2.13 Timer

Asset that measures or records the amount of time taken by a process or activity.

3.2.14 Alarm

Acoustic or electronic warning that is issued to signal an abnormal condition.

3.2.15 Notification

Alert issued to notify a user of an event or condition.

3.2.16 Supervisory System

System that oversees and coordinates operations of lower-level subsystems or processes.

3.2.17 SupervisoryTaskId

Unique identifier for a task within the supervisory system.

3.2.17.1 Untitled

3.2.18 DeviceProgramRunId

Unique identifier for a specific program execution on a device.

3.2.18.1 Untitled

3.2.19 SupervisoryJobId

Unique identifier for a job.

3.2.19.1 Untitled

3.2.19.2 Untitled

3.3 Abbreviations

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}”, the ValueRank is set to the corresponding value (see OPC 10000-3), and ArrayDimensions is set to null or 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 different 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. This is illustrated in Table 2. 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.

Each Type Node or well-known Instance Node defined shall have one or more ConformanceUnits defined in 9.1 that require the Node to be in the AddressSpace.

The relations between Nodes and ConformanceUnits are defined at the end of the tables defining the Nodes, with 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 a 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.

Table 2 provides an example of the table format. 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.

Components of Nodes can be complex; that is, containing components 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 Nodes 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 shown 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 made 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, followed by “.” and its own BrowseName. In this case, “part of” means that the whole has a HasProperty or HasComponent Reference to its part. Since all Nodes which are not 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 for some Nodes to be generated; for example, one for each Session running on the Server. The NodeIds of those Nodes are Server specific, including the Namespace. However, the NamespaceIndex of those Nodes cannot be the NamespaceIndex used for the Nodes defined in this document, as they are not defined by this document but are 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 10.2.

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

If a 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 146 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 whether 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. 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.

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 is Structures without optional fields, where none of the fields allow subtypes (except fields with abstract DataTypes). This is defined in Table 12.

The second kind is Structures with optional fields, where none of the fields allow subtypes (except fields with abstract DataTypes). This is defined 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 is Structures without optional fields, where one or more of the fields allow subtypes. This is defined 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 have subtypes.

4 General information on LADS and OPC UA

4.1 Introduction to LADS

4.1.1 Overview

LADS, an acronym for Laboratory and Analytical Device Standard, is a manufacturer-independent, open standard for analytical and laboratory equipment. It comprehensively encapsulates various customer industries and their respective workflows, providing a sustainable application that also caters to the future demands of digitalization and automation. LADS is built upon OPC UA, an open communication platform developed and promoted by the international non-profit OPC Foundation. OPC UA facilitates cross-vendor communication and interoperability in industrial automation processes.

The benefits of the LADS standard are listed below:

Manufacturer-independent standard

Open standard, capable of integrating instruments in different workflows

Plug and play interoperability of Lab and Analytical Devices

Covers a wide range of different Lab and Analytical devices through device-type-agnostic design principles

Future versions may allow machine-readable semantic contextualization of LADS patterns by linking nodes within the information model to suitable taxonomies and ontologies (utilizing Dictionary References OPC 10000-19)

4.1.2 Introduction to the structure of a LADS Device

The Laboratory and Analytical Device Standard (LADS) Companion Specification provides a comprehensive framework for modelling and managing analytical and laboratory equipment. It does this by defining two primary views: the Hardware View and the Functional View.

4.1.2.1 Hardware View – Devices & Components

The Hardware View focuses on the physical aspects of the devices and their components. This view is essential for various use cases related to asset management, including enhanced serviceability.

Key features of the Hardware View are introduced in the following subsections.

4.1.2.1.1 Devices

These are modelled with properties such as nameplates, installation dates, condition monitoring, and calibration & validation status.

4.1.2.1.2 Components

Hardware components like the Lid, Rotor, Drive, and Compressor are modelled in a sub-tree. Each component exposes its individual nameplate and maintenance-related information, similar to the device itself, and can also have components itself.

4.1.2.1.3 Tasks

Recurrent tasks that affect either the entire device or individual components (such as inspection, maintenance, calibration, validation, cleaning, etc.) can be organized via LADS.

4.1.2.1.4 Example of a Hardware View of a centrifuge

Figure 1 shows a centrifuge, including various components and the corresponding component data.

4.1.2.2 Functional View

The Functional View deals with data relevant for the operation, automation, and orchestration of an instrument.

Key aspects of the Functional View are introduced in the following subsections.

4.1.2.2.1 Functions

Actions to achieve a specific outcome. (Typical functions include but are not limited to sensors, controllers, actuators, timers, etc. They may utilize one or more tangible components.)

The complete list of Functions can be found in section 7.4

Figure 2 shows a centrifuge, including various components and the corresponding component data.

4.1.2.2.2 Programs

Many laboratory and analytical devices allow the user to define and run programs, also called methods. The Program Manager organizes program templates, runs programs, and manages the result data generated during a run, providing device-level orchestration.

4.1.2.2.3 Functional Units

Functional Units are aggregations of functions designed to achieve a specific outcome. Typically, a Functional Unit is utilized by only one user at a time and exposes its current state. It may optionally include a Program Manager. A Functional Unit can be seen as a virtual device within a LADS Device, grouping together several (potentially redundant) functions. This concept is particularly useful when a LADS Device contains multiple functions that can be grouped as virtual devices or behave as separate devices. In such cases, a LADS Device can be divided into multiple Functional Units, with each Functional Unit representing a virtual device.

For instance, consider a bioreactor vessel with two separate interfaces (see Figure 3). Each container has its own functions, such as a temperature sensor and a motor, and its own program. This setup allows the bioreactor to be split into two Functional Units, each representing a separate container with its own program and set of functions.

4.1.3 Introduction to the state machines and Device status variables used

4.1.3.1 Overview

This section provides an overview of the state machines and device status variables used in the LADS Companion Specification. It explains the relationship between various state machines and status variables in the context of a LADS Device, its Components, and Functional Units.

The relationship between these state machines and status variables is crucial for understanding the operation and management of a LADS Device. The state of the LADS Device state machine and the FunctionalUnit state machines come first and form the basis for the MachineryItemState. The MachineryOperationMode provides additional context about the type of Tasks being performed. The DeviceHealth and DeviceHealthAlarms provide information about the device's condition and any Alarms that may have been triggered.

Refer to Annex B for proposed mappings between the DeviceStateMachine, the FunctionalUnit state machines, the MachineryItemState and the DeviceHealth.

4.1.3.2 Device State Machines

The DeviceStateMachine provides a domain-specific view of the device's state. It reflects the condition of the Device itself.

4.1.3.3 MachineryItemState

The MachineryItemState provides a harmonized state machine across various domains, particularly in mechanical engineering. It serves as a semantic stack light, providing a high-level system with a quick overview of the device's operational status.

4.1.3.4 MachineryOperationMode

The MachineryOperationMode indicates the type of Tasks being performed by the Device. It may not be known by the MachineryItem itself and might need to be provided by an external source, like an MES system or the operator.

4.1.3.5 FunctionalUnit State Machines

Each FunctionalUnit within a LADS Device has an independent FunctionalUnit state machine. For instance, a device with three FunctionalUnits will have three separate FunctionalUnit state machines. These state machines are process oriented and can operate independently. They may also include sub-state machines for the running state. These state machines come first, and their states form the basis for the MachineryItemState.

4.1.3.6 ControlFunction state machines

ControlFunctions also have a FunctionStateMachine, similar to the FunctionalUnitStateMachine. This state machine provides a detailed view of the operational state of the ControlFunctions.

4.1.3.7 DeviceHealth and ComponentDeviceHealth

The DeviceHealth and DeviceHealthAlarms provide information about the device's condition and any Alarms that may have been triggered. They are optional and can be implemented at both the Device and Component levels. The DeviceHealth status variable provides a quick overview of the device's health status, while the DeviceHealthAlarms variable provides detailed information about any specific Alarms that may have been triggered.

4.1.4 Program and result lifetime of a LADS Device

The lifetime of a program, from uploading a program template to the creation of the result, including additional information about the ActiveProgramType and the RunningStateMachineType, is as follows:

Uploading Program Template: The client uploads the ProgramTemplate to the ProgramTemplateSet of the ProgramManager using the Upload Method.

Starting the Program Execution: The program can be started either externally by a Client application using the Start or StartProgram Method or internally by the Device itself based on internal/process reasons.

Program Execution: The program execution progresses through various states defined in the FunctionalStateMachineType. During program execution, the ActiveProgramType provides information about the current state and runtime of the program. The CurrentPauseTime and CurrentRuntime properties indicate the current pause time and runtime of the program run, respectively. The CurrentStepName and CurrentStepNumber properties provide information about the current step being executed. The EstimatedRuntime, EstimatedStepNumbers, and EstimatedStepRuntime properties provide estimated information about the program's total runtime and steps.

Creating Results: As the program is executed, the FunctionalUnit generates data and results during the run. These results are collected in a result object which is managed in the ResultSet, which includes information about the program's initiator, the template used with additional parameters, samples, and contextual information to link and trace the results. The result object can provide the results either as files in the FileSet or as OPC UA variables in the VariableSet.

Program Completion: The program execution continues until it reaches the completion state (e.g., complete state) in the RunningStateMachineType. Once the program is complete, the results in the ResultSet are considered complete and are available for further processing and analysis.

Please note that the program's lifetime and states may vary based on the specific implementation and context of the OPC UA Companion Specification being used. The provided overview is a general outline of the program's lifetime and the high-level information about the ActiveProgramType and ResultSet based on the description provided.

This is illustrated in Figure 4

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-the-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 economies of scale for application developers. This means that a larger number of high-quality applications are available at a reasonable cost. When combined with semantic models such as LADS, 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 example. 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 means 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 visualisation 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 5.

OPC UA provides a robust and reliable communication infrastructure with 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 a BrowseName. An Object representing a “Reservation” is shown in Figure 6.

Object and Variable Nodes represent instances and always reference a TypeDefinition (ObjectType or VariableType) Node which describes their semantics and structure. Figure 7 illustrates the relationship between an instance and its TypeDefinition.

Type Nodes are templates that define all the children that can be present in an instance of the type. In the example in Figure 7 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 are implemented on multiple Servers.

OPC UA also supports the concept of subtyping. This allows a modeller to take an existing type and extend it. Rules regarding subtyping are 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 needs an additional Variable in some cases. 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 were of the parent type. Regarding DataTypes, subtypes can only restrict. If a Variable is defined to have a numeric value, a subtype 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 references 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 8 depicts several References connecting different Objects.

The figures above use a notation that was developed for the OPC UA specification. This notation is summarized in Figure 9. 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.

The OPC UA specification defines a very wide range of functionalities in its basic information model. It is not required that all Clients or Servers support all functionalities 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. Profiles do not restrict functionality, but they generate requirements for a minimum set of functionalities (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 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, as well as potentially well-defined Objects as entry points into the AddressSpace.

5 Use cases

This section introduces the use cases addressed by the LADS specification.

5.1 Automation

5.1.1 Remote monitoring, Alarms, Notifications

Description

Remote monitoring, Alarms and Events form the foundation of any basic automation functionality. If no information is available regarding the current values of function states, operation modes, process variables, set-points, parameters, etc. it is not possible to make decisions and take action. For selected values, such as Sensor or process values, the optional provision of time-series history services is recommended.

Remote monitoring entails the capability to measure a physical/chemical/biological property. It comprises of a “raw” measurement value provided by the sensing element, a calibration function, optional signal processing/filtering and the final Sensor value which represents a real-world physical/chemical/biological property.

The remote monitoring of a property may be augmented by Alarm and Notification functionalities which update the user regarding the monitored property value matching determined conditions (e.g., out of limits).

History services are supported to retrieve historic information on the observed properties.

Addressed in Sections: 7.1

5.1.2 Function-based remote control

Description

Function-based remote control enables a user to remotely perform an action, change parameters or setpoints, or start and stop Functions. It includes the remote invocation of Methods to perform Functions on a Device. For example, to start or stop device-specific Functions, open and close covers, as well as change parameters like Alarm limits, control and calibration values, or closed-loop control set-point values.

Addressed in Sections: 7.4 , 7.6 , 7.4.2

5.1.3 Program-based remote control

Description

Program-based remote control covers the orchestration of one or more instruments along a lab or analytical workflow. It enables a supervising system (e.g., LIMS) to manage and execute programs on a Device as part of a greater workflow. 

Furthermore, it covers the capability to retrieve the Program Templates on the Device, select a program to be executed, start a program run and monitor the program’s progress.

The combined program-management and result-management use-cases are the basis for orchestration of several instruments along workflows. 

Addressed in Section: 7.1.10

5.1.4 Results management

Description

A Device performing a specific Function may generate results. These results are typically consumed by one or more applications which may not run on the Device itself.

The generating Device exposes the results such that they can be retrieved by the application via OPC UA. The results data include the results themselves, but also metadata such as results templates, user information, timestamps, action identifiers, and sample Ids.

A Device can also provide the capability to observe intermediate/partial results, such that an application can monitor the execution of a Function on the Device.

There may be specific cases in which a consuming application may need to retrieve the results via an alternative interface. In these cases, the Device exposes the URI where the results reside and can be accessed via authenticated access. The possibility to retrieve intermediate/partial results via an alternative interface is outside the scope of this specification.

Addressed in Sections: 7.1.10 , 7.2.2 , 7.2.3

5.2 Service and asset management

5.2.1 Device and fleet management

Description

Devices typically come with a set of properties that identify them for discovery, management, and maintenance purposes. This set of properties is commonly summarized using the term “nameplate“. The information available includes (but it is not limited to) device name, identifiers, serial number, manufacturer, hardware and software versions, and product URI. A nameplate for a device is required to be recognized correctly in the server.

Furthermore, a Device is composed of different Components. Each of these Components can have a nameplate itself. The definition of Components is up to the implementer of the Device.

It should be possible to represent an individual Device as an OPC UA Server or aggregate multiple Devices into the same OPC UA Server. Therefore, an OPC UA Server can represent an arbitrary number of Devices. The following scenarios are envisioned to be covered by this specification:

Single Devices incorporating an OPC UA Server,

Gateway Devices representing a set of Devices, including OPC UA capable Devices as well as non-OPC UA capable Devices (e.g., a simple analogue Sensor or legacy device using a different communication protocol),

Devices serving both of the above roles.

Addressed in Section: 7.1

5.2.2 Condition monitoring and maintenance

Description

The condition of a Device or a Component of a device is useful for understanding its health status and performance, as well as possible maintenance actions needed. For these reasons, the following information is envisioned to be represented for a Device or Component:

Indicators of health status,

Indicators of operating time and number of actions performed since installation or maintenance,

Indicators of (estimated) remaining lifetime based on the device information provided by suppliers,

Device modes (e.g., operating, sleep, maintenance, off) and Methods to trigger changes.

For maintenance purposes, the possibility to trigger, record, and retrieve information related to maintenance activities is seen as valuable.

Maintenance activities can be recurrent, periodic, or ad-hoc. They can be vendor defined (e.g., yearly maintenance) or user defined (e.g., calibration). Maintenance activities may be initiated based on specific conditions related to the health and condition of a Device or a Component. History with dates and details of actions performed on a Device or a Component should be available.

Addressed in Sections: 0 7.1.1 , Error! Reference source not found.

5.2.3 Location

Description

The location of a Device is of interest for multiple purposes. These include:

Finding a Device position for asset management and service needs

Enabling autonomous robots to navigate within a lab facility or across multiple lab facilities

Sample location tracking (future).

A Device location can include different information, including:

Geographical

Address

Organizational

Indoor coordinates

GPS coordinates.

Addressed in Section: 7.1

6 LADS Information Model Overview

This Companion Specification is based on OPC 10000-100 (Devices), OPC 10000-110 (Asset Management Basics) and OPC 40001-1 (OPC UA for Machinery). These Companion Specifications create an entry point for Devices or machines in the AddressSpace. Instances of a LADSDeviceType shall either directly or indirectly referenced with a Hierarchical Reference to the DeviceSet and can be referenced from Machines with an Organizes Reference.

A LADSDeviceType may have both References (to DeviceSet and Machines), depending on the environment of the Device. Both References are needed if the LADSDeviceType is used in a production environment or in a laboratory close to production.

Figure 10 shows an example representation of a LADSDeviceType instance in the AddressSpace.

Figure 11 shows the type definition of the LADSDeviceType.

Figure 12 shows the type definition of the LadsComponentType.

Figure 13 shows the FunctionType inheritance in the LADS type space.

Figure 14 shows the FunctionalStateMachineType inheritance.

7 OPC UA ObjectTypes

7.1 Type for Devices, Components and FunctionalUnits

7.1.1 LADSDeviceType ObjectType Definition

The LADSDeviceType provides a base class for Laboratory and Analytical Devices. It is formally defined in Table 15.

Components is a generic set of identifiable sub-components of the Device as mandated by OPC 40001-1.

FunctionalUnitSet contains the Functional Units of this Device.

HierarchicalLocation provides the hierarchical location of the LADS Device. The structure within the string may expose several levels. How this is exposed, which delimiters are used, etc. is vendor specific. Examples of such strings are “FactoryA/BuildingC/Floor1” or “Area1-ProcessCell17-Unit4” (see OPC UA OPC 10000-110 for more details).

OperationalLocation provides the operational location of the LADS Device. The structure within the string may expose several levels. How this is exposed, which delimiters are used, etc. is vendor specific. Examples of such strings are “Warehouse1/Sheet3” or “StainlessSteelTote3” (see OPC UA OPC 10000-110 for more details).

Recommendations for both hierarchical and operational locations have been proposed:

For instances where the location definition encompasses multiple levels, these levels should be separated by the delimiter character "/". An instance of a location definition with multiple levels separated by the delimiting character "/" is "US-NY-NYC-Building101/Floor35/Room10.1".

For additional use cases not covered by the aforementioned properties, it is recommended to employ the additional location formats NmeaCoordinateString, LocalCoordinate, and WGS84Coordinate as delineated in the OPC UA for AutoId Devices Release 1.01.1 (2021-07-13) specification.

Identification provides properties to identify a Device.

Recommendations for the Identification:

If the device consists solely of software with no hardware, the SoftwareRevision should be provided, and the HardwareRevision should be omitted.

If the device consists solely of hardware with no software, the HardwareRevision should be provided, and the SoftwareRevision should be omitted.

If the device consists of both hardware and software, the HardwareRevision should be provided. The SoftwareRevision should be provided if there are no device components providing a SoftwareRevision. Otherwise, the SoftwareRevision may be provided to represent the overall revision of all software components.

If a ProductInstanceUri can be created, this property should be part of the Identification.

OperationCounters for monitoring the operation of a LADSDeviceType, including parameters of the OperationCounters interface and lifetime variables (see OPC UA for Devices for more information).

DeviceState StateMachine that controls and represents the Device’s current state.

Maintenance is a set containing all maintenance tasks of a Device.

The MachineryBuildingBlocks folder contains all machinery building blocks, especially the MachineryItemState, MachineryOperationMode, OperationCounter and Lifetime Counter.

Refer to Annex B for proposed mappings between the DeviceStateMachine, the FunctionalUnit state machines, the MachineryItemState and the DeviceHealth.

MachineryItemState indicates the current state of the device and is comparable with the LADS Device state machine.

MachineryOperationMode indicates the type of Tasks being performed by the Device.

OperationCounter provides information on how long a MachineryItem has been turned on and how long it performed an activity. It uses the 2:IOperationCounterType interface and the predefined functional group 2:OperationCounters defined in OPC 10000-100.

Lifetime Counter provides information about the past and estimated remaining lifetime of a MachineryItem, or other aspects of a MachineryItem such as a software license. It is based on the 2:LifetimeVariableType defined in OPC 10000-100.

Children of the LADSDeviceType have additional References, which are defined in Table 16.

7.1.2 LADSDeviceStateMachineType ObjectType Definition

7.1.2.1 Overview

The LADSDeviceStateMachineType state machine represents the Device’s current state. It is inspired by the AnalyserDeviceStateMachineType from the Analyzer Devices Specification.

The LADSDeviceStateMachine is depicted in Figure 15

The LADSDeviceStateMachineType is formally defined in Table 17.

There are four Device states, as follows:

Initialization: The Device is in its initializing sequence and cannot perform any other Task.

Operate: The Device is in Operating mode. The LADS Client uses this mode for normal operation: configuration, control, and data collection.

Sleep: The Device is still powered on and its OPC UA Server is still running, but it is not ready to perform any Tasks until it transitions to the Operate state. This state can be used to represent a PowerSave state where a Device may shut down some of its Components, such as the GUI. It can also be used to represent a Sleep state, where a Device is running with minimal services but ready to be triggered to transition into the Operate state.

Shutdown: The Device is in its power-down sequence and cannot perform any other Task. Optionally, there are devices that can be powered off via physical means, especially simpler ones. The electronics are turned off immediately; therefore, such devices do not transition into a Shutdown state.

Note: Shutdown is the state in which the LADS Device waits for the completion of the power down sequence. Its sub-states are out of scope of the LADS specification.

Children of the LADSDeviceStateMachineType have additional References, which are defined in Table 18.

The Component Variables of the LADSDeviceStateMachineType have additional Attributes, as defined in Table 19.

7.1.2.2 GotoOperate

The GotoOperate Method is used to set the Device into an operating mode. The signature of this Method is specified below. Table 20 specifies its representation in the AddressSpace.

Signature

	GotoOperate ()

7.1.2.3 GotoShutdown

The GotoShutdown Method is used to shut down the Device. The signature of this Method is specified below. Table 21 specifies its representation in the AddressSpace.

Signature

	GotoShutdown ()

7.1.2.4 GotoSleep

The GotoSleep Method is used to set the Device to Sleep. The signature of this Method is specified below. Table 22 specifies its representation in the AddressSpace.

Signature

	GotoSleep ()

7.1.3 LADSComponentType ObjectType Definition

Devices may be composed of tangible subcomponents. A Component is represented by the LADSComponentType. A Component itself may also have subcomponents. The LADSComponentType is formally defined in Table 23.

Components is a generic set of identifiable subcomponents of the device as mandated by OPC 40001-1.

Identification provides the properties to identify a device.

Recommendations for Identification:

• If the Component consists solely of software with no hardware, the SoftwareRevision should be provided and the HardwareRevision should be omitted.

• If the Component consists solely of hardware with no software, the HardwareRevision should be provided and the SoftwareRevision should be omitted.

• If the Component consists of both hardware and software, the HardwareRevision should be provided. The SoftwareRevision should be provided if there are no subcomponents providing a SoftwareRevision. Otherwise, the SoftwareRevision may be provided to represent the overall revision of all software components.

HierarchicalLocation provides the hierarchical location of the LADS Device. The structure inside the string may expose several levels. How this is exposed, which delimiters are used, etc. is vendor specific. Examples of such strings are “FactoryA/BuildingC/Floor1” or “Area1-ProcessCell17-Unit4” (see OPC 10000-110 for more Details).

OperationalLocation provides the operational location of the LADS Device. The structure within the string may expose several levels. How this is exposed, which delimiters are used, etc. is vendor specific. Examples of such strings are “Warehouse1/Sheet3” or “StainlessSteelTote3” (see OPC 10000-110 for more Details).

Recommendations for both hierarchical and operational locations have been proposed:

For instances where the location definition encompasses multiple levels, these levels should be separated by the delimiter character "/". An instance of a location definition with multiple levels separated by the delimiting character "/" is "US-NY-NYC-Building101/Floor35/Room10.1".

For additional use cases not covered by the aforementioned properties, it is recommended to employ the additional location formats NmeaCoordinateString, LocalCoordinate, and WGS84Coordinate as delineated in the OPC UA for AutoId Devices Release 1.01.1 (2021-07-13) specification.

DeviceHealth indicates the health status of a Device as defined by NAMUR Recommendation NE 107 (see OPC 10000-100 for more Details).

DeviceHealthAlarms groups all instances of Device health-related Alarms.

OperationCounters for monitoring the operation of a LADSDeviceType, including parameters of the OperationCounters interface and lifetime variables (see OPC 10000-100 for more information).

Maintenance is a set containing all maintenance tasks of a Device.

The MachineryBuildingBlocks folder contains all machinery building blocks, especially the OperationCounter, and Lifetime Counter.

OperationCounter provides information on how long a MachineryItem has been turned on and how long it performed an activity. It uses the 2:IOperationCounterType interface and the predefined functional group 2:OperationCounters defined in OPC 10000-100.

Lifetime Counter provides information about the past and estimated remaining lifetime of a MachineryItem, or other aspects of a MachineryItem such as a software license. It is based on the 2:LifetimeVariableType defined in OPC 10000-100.

Children of the LADSComponentsType have additional References, which are defined in Table 24.

7.1.4 FunctionalUnitType ObjectType Definition

The FunctionalUnitType represents a functional unit of a Laboratory or Analytical Device. It is formally defined in Table 25.

AssetId is a user-writeable alphanumeric character sequence that uniquely identifies a FunctionalUnit (see OPC UA 10000-100).

ComponentName is a user-writeable name provided by the integrator or user of the FunctionalUnit.

FunctionSet contains the Functions of the FunctionalUnit.

Program Manager manages the programs and results of the FunctionalUnit.

FunctionalUnitState the StateMachine that is used for this FunctionalUnit.

Operational Functional Group that organizes Properties and Methods for this FunctionalUnit.

SupportedPropertiesSet provides references to variables of sub-ordinate Functions of the FunctionalUnit whose values can be specified as input Arguments when calling the FunctionalUnit.FunctionalUnitState.Start() or ProgramManager.ActiveProgram.StateMachine.Start() Methods.

7.1.5 FunctionalStateMachineType ObjectType Definition

7.1.5.1 Overview

The FunctionalStateMachineType is the top level StateMachine for the LADS ActiveProgram, FunctionalUnit or Function. The basic idea behind this architecture is that the instances of the FunctionalStateMachineType, the ActiveProgramStateMachineType, the FunctionalUnitStateMachineType and the FunctionStateMachineType use the same states, Transitions and Methods, but add their own Start Methods with different Method Signatures to trigger the StoppedToRunning Transition from a Client.

The FunctionalStateMachineType defines the available states in a LADS system.

The FunctionalStateMachineType is formally defined in Table 26. StateTypes and TransitionTypes only exist in the type system, thus they do not have a modelling rule.

The FunctionalStateMachine is depicted in Figure 16.

The AvailableTransitions and AvailableStates Nodes are overwritten and made Mandatory in the FunctionalStateMachineType.

Abort is a Method to trigger a change of state to Aborting. This will affect all sub-states in a cleared state.

Aborted maintains unit/device status information relevant to the Abort condition. The unit/device can only exit the Aborted state after an explicit Clear command subsequent to manual intervention to correct and reset the detected unit/device faults.

Aborting represents a state that can be entered at any time in response to the Abort command or in the event of a unit/device fault. The aborting logic will bring the unit/device to a rapid safe stop. Operation of the emergency stop will cause the unit/device to be tripped by its safety system. It will also provide a signal to initiate the Aborting state.

Clear is a Method to trigger a change of state to Cleared.

Clearing is initiated by a state command to clear faults that may have occurred when Aborting that are present in the Aborted state.

Running is the state when the ActiveProgram, Function or FunctionalUnit is currently running/executing.

RunningStateMachine is a RunningStateMachineType that details the Running state.

Stop is a Method to trigger a change of state to Stopped. This will affect all sub-states in a Run state.

Stopped is the initial state for an ActiveProgram, FunctionalUnit or Function. It is an Idle state which means that the Function, FunctionalUnit or ActiveProgram is stopped and ready for activation. It can also be used to represent a non-running state, potentially caused by an error, where the Function, FunctionalUnit or ActiveProgram can invoke the Reset() Function before starting again.

Stopping indicates that the ActiveProgram, FunctionalUnit, or Function is in the process of stopping. This state usually occurs when the program execution is finished or stopped, either because it has ended or has been triggered by the Stop Method.

The Transitions of the FunctionalStateMachineType have additional References which are defined in Table 27. This StateMachine includes the transition from Unholding to Holding, Starting, Unsuspending, Suspended, and Suspending, all of which are extensions to the ISA-TR88.00.02-2015 specification.

The Component Variables of the FunctionalStateMachineType have additional Attributes, as defined in Table 28.

7.1.5.2 Abort

The Abort Method switches the state machine to the Aborting state. The current process will be aborted. The signature of this Method is specified below. Table 29 specifies its representation in the AddressSpace.

Signature

	Abort ()

7.1.5.3 Clear

The Clear Method allows an OPC UA Client to change the state of this state machine to the Cleared state. The signature of this Method is specified below. Table 30 specifies its representation in the AddressSpace.

Signature

	Clear ()

7.1.5.4 Stop

The Stop Method allows an OPC UA Client to change the state of this state machine to the Stopping state. The signature of this Method is specified below. Table 31 specifies the Arguments and AddressSpace representation.

Signature

	Stop ()

7.1.6 RunningStateMachineType ObjectType Definition

7.1.6.1 Overview

The RunningStateMachineType is a sub-state machine of the FunctionalStateMachine and includes detailed substates. It is formally defined in Table 32.

The Running StateMachine is depicted in Figure 17.

Complete: Complete indicates that the process associated with the active protocol has come to its defined end. The unit/device will wait in this state until a Reset command is issued (in which case it will transition to Resetting), or until the unit/device is Stopped or Aborted.

Completing: Once the process associated with the current mode has reached a defined threshold (e.g., the required number of samples for the current job have been analysed or the cultivation/fermentation process has reached is final stage in terms of cell count, product yield, cell viability, etc.), the unit/device transitions from Execute to Completing. All steps necessary to shut down the current process are carried out in this state. The unit/device then transitions automatically to the Complete state.

Execute: The unit/device is actively carrying out the behaviour or activity defined by the selected protocol and its associated processing mode. Examples of a unit/device in processing mode include when the unit/device is performing an analytical run, cultivation/fermentation in the case of a bioreactor, or another defined unit of operation provided by the instrument (e.g., separation in the case of a centrifuge).

Held: The unit/device is paused, waiting for internal process conditions to clear. In this state, the unit/device shall not continue processing, although it may dry cycle if required (e.g., maintaining process conditions critical for the preservation of the samples or culture). A transition to Unholding will occur once internal unit/device conditions have cleared, or if the Unhold command is initiated by an operator.

Holding: The unit/device will transition from Execute to Holding if conditions internal to the unit/device require a pause in processing. Examples of such conditions include low levels of materials required for processing (e.g., consumables, reagents, buffers, etc.) or other minor issues requiring operator service. After all steps required to hold the unit/device have been completed, the unit/device will transition automatically to the Held state.

Idle: The unit/device is in an error-free state, waiting to start. The unit/device transitions automatically to Idle after all steps necessary for Resetting have been completed. All conditions achieved during Resetting are maintained. A Start command will transition the unit/device from Idle to Starting.

Resetting: In response to a Reset command, the unit/device will transition to Resetting from either Stopped or Complete. In this state the unit/device attempts to clear any standing errors or stop causes. If successful, the unit/device transitions to Idle. No hazardous motion should occur while in this state.

Starting: The unit/device completes all steps necessary to begin execution of the active protocol. Typical steps during this state include but are not limited to inspecting system setup (checking sufficient supplies of resources and consumables), priming of fluids, homing of handling systems, or equilibration of process conditions. A Start command will cause the unit/device to transition from Idle to Starting. The unit/device will transition automatically from Starting to Execute once all required steps have been completed.

Suspended: The unit/device is paused, waiting for external process conditions to clear. In this state, the unit/device shall not continue processing, but may dry cycle if required (e.g., maintaining process conditions critical for the preservation of the samples or culture, including but not limited to temperature, oxygen or pH levels, etc.). Once external conditions have returned to normal, the unit/device will transition to Unsuspending, with or without operator intervention.

Suspending: The unit/device will transition from Execute to Suspending if conditions external to the unit/device require a pause in processing. Such conditions include faults to upstream or downstream equipment. The decision to Suspend may be made by a human operator supervising the process, an automated supervisory system monitoring the conditions of the overall process line/workflow, or by unit/device Sensors detecting downstream blockages or upstream scarcity of samples, etc. (In the former case, the unit/device is ‘blocked”; in the latter case, the unit/device is “starved”.) After all steps required to suspend the unit/device have been completed, the unit/device will automatically transition to the Suspended state.

Unholding: After all internal process conditions that caused the unit/device to hold have cleared, the unit/device completes all steps required to resume execution of the active protocol. Once all required actions to unhold the unit/device have been completed, the unit/device will transition automatically to the Execute state.

Unsuspending: After all external process conditions that caused the unit/device to suspend have cleared, the unit/device completes all steps required to resume execution of the active protocol.

The children of the RunningStateMachineType have additional References, which are defined in Table 33.

The Component Variables of the RunningStateMachineType have additional Attributes, as defined in Table 34.

7.1.6.2 Hold

The Hold Method allows an OPC UA Client to change the state of this state machine to Holding. The signature of this Method is specified below. Table 35 specifies its representation in the AddressSpace.

Signature

	Hold ()

7.1.6.3 Reset

The Reset Method allows an OPC UA Client to change the state of this state machine to Resetting. The signature of this Method is specified below. Table 36 specifies its representation in the AddressSpace.

Signature

	Reset ()

7.1.6.4 Suspend

The Suspend Method allows an OPC UA Client to change the state of this state machine to the Suspending state. The signature of this Method is specified below. Table 37 specifies its representation in the AddressSpace.

Signature

	Suspend ()

7.1.6.5 ToComplete

The ToComplete Method allows an OPC UA Client to change the state of this state machine to Completed. The signature of this Method is specified below. Table 38 specifies its representation in the AddressSpace.

Signature

	ToComplete ()

7.1.6.6 Unhold

The Unhold Method allows an OPC UA Client to change the state of this state machine to Unholding. The signature of this Method is specified below. Table 39 specifies its representation in the AddressSpace.

Signature

	Unhold ()

7.1.6.7 Unsuspend

The Unsuspend Method allows an OPC UA Client to change the state of this state machine to Unsuspending. The signature of this Method is specified below. Table 40 specifies its representation in the AddressSpace.

Signature

	Unsuspend ()

7.1.7 FunctionalUnitStateMachineType Definition

7.1.7.1 Overview

The FunctionalUnitStateMachineType represents the state of a FunctionalUnit in a LADS Device. It uses the same StateTypes and TransitionTypes as its parent but specifies the additional Start Method to trigger state changes.

The FunctionalUnitStateMachineType is formally defined in Table 41.

Start is used to start a FunctionalUnit with properties.

StartProgram is used to start a FunctionalUnit with a Program Template.

7.1.7.2 Start

The Start Method is used when a Client application wants to initiate/execute an/the operation of a FunctionalUnit. The Properties Argument can be used to provide an optional list of property values when initiating the operation. The listed items represent key-value pairs that conform to the OPC UA KeyValuePair core datatype. The qualified name provided via the key field must match the BrowseName of a Property member in the FunctionalUnit’s SupportedPropertySet.

The signature of this Method is specified below. Table 42 and Table 43 specify the Arguments and AddressSpace representation, respectively.

The Start Method should not be called by a Client with anonymous authentication.

Signature

	Start (
		[in]	KeyValuePair[]	Properties)

7.1.7.3 StartProgram

The StartProgram Method is used when a Client application wants to start running a program based on a ProgramTemplate of a FunctionalUnit. The Properties Argument can be used to provide an optional list of property values when initiating a program run. The listed items represent key-value pairs that conform to the OPC UA KeyValuePair core datatype. The qualified name provided via the key field must match the BrowseName of a Property member in the FunctionalUnit’s SupportedPropertySet.

In contrast to the Start Method, additional fixed properties must also be set.

The signature of this Method is specified below. Table 44 and Table 45 specify the Arguments and AddressSpace representation, respectively.

The Start Method should not be called by a Client with anonymous authentication.

Signature

	StartProgram (
		[in]	0:String	ProgramTemplateId
		[in]	KeyValueType[]	Properties
		[in]	0:String	SupervisoryJobId
		[in]	0:String	SupervisoryTaskId
		[in]	SampleInfoType[]	Samples
		[out]	0:String	DeviceProgramRunId)

DeviceProgramRunId is the internal program identifier assigned by the Device to the program run to generate this result. It is used to identify a Result object and is returned to the Client when the StartProgram Method is called.

SupervisoryJobId is the identifier for the execution of a specific workflow, consisting of one or multiple tasks. It is provided as an Argument of the StartProgram() Method which initiates the program run.

SupervisoryTaskId is the unique identifier of the specific task in the supervisory system to which the result belongs. It is provided as an Argument of the StartProgram() Method which initiates the program run.

7.1.8 LADSComponentsType ObjectType Definition

The LADSComponentsType is used for organising LADSComponentsType objects in an unordered list structure. It is formally defined in Table 46.

<Components> is a placeholder for the Components.

7.1.9 LADSOperationModeStateMachineType ObjectType Definition

The LADSOperationModeStateMachineType is a subtype of 4:MachineryOperationModeStateMachineType that adds optional Methods to the statemachine. It is formally defined in Table 46.

7.1.9.1 GotoMaintenance

The GotoMaintenance Method brings the LADSDevice in the Maintenance state.

The signature of this Method is specified below. Table 52 specifies its representation in the AddressSpace.

Signature

	GotoMaintenance ()

7.1.9.2 GotoProcessing

The GotoMaintenance Method brings the LADSDevice in the Processing state.

The signature of this Method is specified below. Table 52 specifies its representation in the AddressSpace.

Signature

	GotoProcessing ()

7.1.9.3 GotoSetup

The GotoSetup Method brings the LADSDevice in the Setup state.

The signature of this Method is specified below. Table 52 specifies its representation in the AddressSpace.

Signature

	GotoSetup ()

7.1.10 MaintenanceTaskType Definition

7.1.10.1 Overview