This Annex provides a mapping of ISA/IEC 62443 to OPC UA. The first 5 columns (yellow color) in each table are from the IEC 62443 specification and are included here for clarity. Some topics in ISA/IEC 62443 do not apply to OPC UA and are marked as “N”. ISA/IEC 62443 topics that do apply are marked as “Y”. ISA/IEC 62443 topics that are partially covered are marked as “P”, For each topic that does apply the table lists the relevant OPC UA Parts and the Profiles/ ConformanceUnits that covers the listed functionality. For each OPC UA Part that is listed (other than OPC 10000-7) the text in the “Keyword text or comment” column is the text that should be searched for. The section that are found related to the keyword will describe the OPC UA related functionality. For the row labelled OPC 10000-7, the keyword column contains the actual Profile or ConformanceUnits that apply. For more detail on the ConformanceUnit or Profile, please use the on-line Profile Application available at https://profiles.opcfoundation.org.

Columns 2 through 4 in each of the tables could include a checkmark. The check marks when present indicate that the specific 62443 requirement applies to the listed security level (SL). This information is provided by the IEC 62443 specification and is reproduced here as a convenience.

The tables are broken into seven separate tables, one for each of the foundational requirements;

  1. Identification and authentication control (Table A.)
  2. Use control (Table A.)
  3. System integrity (Table A.)
  4. Data confidentiality (Table A.)
  5. Restricted data flow (Table A.)
  6. Timely response to events (Table A.)
  7. Resource availability (Table A.)

Table A.1 ISA/IEC 62443 Mapping FR 1 Identification and authentication control

ISA-62443-4-2

CRs and Res

Related to

Applies to OPC UA

OPC UA Part #

Keyword text or comment

SL1

SL2

SL3

SL4

CR 1.1: Human user identification and authentication

Y

OPC 10000-4

IssuedIdentityToken

OPC 10000-6

JSON Web Token (JWT), JWT UserTokenPolicy

OPC 10000-7

Security User JWT IssuedToken, Security User JWT Token Policy, OPC UA Authority Profile

CR 1.1 RE (1): Unique identification and Authentication

Y

OPC 10000-4

IssuedIdentityToken

OPC 10000-6

JSON Web Token (JWT), JWT UserTokenPolicy

OPC 10000-7

Security User JWT IssuedToken, Security User JWT Token Policy, OPC UA Authority Profile

User Token JWT Server Facet, User Token JWT Client Facet

CR1.1 RE(2) Multifactor authentication for all interfaces`

P

OPC UA does not define any alternate schemes for two factor authentication, but if Issued tokens are used for user Authentication, the issued token provider can implement multifactor authentication. OPC UA authenticates the application as well as the user.

OPC 10000-4

IssuedIdentityToken

OPC 10000-6

JSON Web Token (JWT), JWT UserTokenPolicy

OPC 10000-7

Security User JWT IssuedToken, Security User JWT Token Policy, OPC UA Authority Profile

User Token JWT Server Facet, User Token JWT Client Facet

CR 1.2: Software process and device identification and authentication

Y

OPC 10000-2

ApplicationAuthentication, X.509 v3 Security Certificates

OPC 10000-4

ApplicationInstance Security Certificate

OPC 10000-6

EndpointDescription, EndpointUrl, Hostname (Device)

OPC 10000-7

Security Default ApplicationInstance Security Certificate, Global Security Certificate Management Server Facet

CR 1.2 RE (1) Unique identification and authentication

Y

OPC 10000-2

ApplicationAuthentication, X.509 v3 Security Certificates

OPC 10000-4

ApplicationInstance Security Certificate

OPC 10000-6

EndpointDescription, EndpointUrl, Hostname (Device)

OPC 10000-7

Security Default ApplicationInstance Security Certificate, Global Security Certificate Management Server Facet

CR 1.3: Account management

P

OPC UA does not directly provide account management, but if an AuthorizationService is used for user Authentication, it could support account management

OPC 10000-4

IssuedIdentityToken

OPC 10000-6

JSON Web Token (JWT), JWT UserTokenPolicy

OPC 10000-7

Security User JWT IssuedToken, Security User JWT Token Policy, OPC UA Authority Profile

User Token JWT Server Facet, User Token JWT Client Facet

CR 1.4: Identifier management

Y

OPC 10000-4

UserIdentityToken, UserTokenPolicy

OPC 10000-7

Security User JWT IssuedToken, Security User JWT Token Policy, OPC UA Authority Profile

User Token JWT Server Facet, User Token JWT Client Facet

CR 1.5: Authenticator management

Y

OPC 10000-4

UserIdentityToken, UserTokenPolicy

OPC 10000-7

Security User JWT IssuedToken, Security User JWT Token Policy, OPC UA Authority Profile

User Token JWT Server Facet, User Token JWT Client Facet

CR 1. 5 RE (1) Hardware security for authenticators

N

Secure elements are recommended in 9.1 and also discussed in OPC 10000-12 and OPC 10000-21, but not defined in OPC.

NDR 1.6 – Wireless access management

N

OPC UA does specify physical characteristics of a network including wireless.

NDR 1.6 RE (1) Unique identification and authentication

N

Same as above

CR 1.7: Strength of password based authentication

N

OPC UA provides the mechanism for exchanging passwords information, but it does not define the implementation of the password – this is vendor specific. If an AuthorizationService is used, it can provide password strength enforcement

CR 1.7 RE (1) Password generation and lifetime restrictions for human users

N

Same as CR 1.7 above

CR 1.7 RE (2) Password lifetime restrictions for all users (human, software process, or device)

N

Same as CR 1.7 above

CR 1.8: Security certificates

Y

OPC 10000-2

Security Certificates, TrustLists (CertificateStore), OPC UA Security Services

OPC 10000-4

Obtaining, validating, and installing Security Certificate services

OPC 10000-6

Security Certificates

OPC 10000-7

Security Administration, Global Security Certificate Management

OPC 10000-12

Security Certificate Management Overview

CR 1.9: Strength of public key-based authentication

Y

OPC 10000-2

Cryptographic Keys

OPC 10000-4

Trusted Security Certificates

OPC 10000-7

Security Profiles: Basic256_Limits, SecurityPolicy [B] – Basic256Sha256

CR 1.9 RE (1) Hardware security for public key-based authentication

N

Secure elements are recommended in 9.1 and also discussed in OPC 10000-12 and OPC 10000-21, but not defined in OPC.

CR 1.10: Authenticator feedback

Y

OPC 10000-2

ApplicationAuthentication, X.509 v3 Security Certificates

OPC 10000-4

ApplicationInstance Security Certificate

OPC 10000-6

EndpointDescription, EndpointUrl, Hostname (Device)

OPC 10000-7

Security Default ApplicationInstance Security Certificate, Global Security Certificate Management Server Facet

CR 1.11: Unsuccessful login attempts

N

OPC does not provide temporary lock out for user access failure, but an AuthenticationService could. OPC does monitor SecureChannel connection and could block secure channel connection for repeated failure.

CR 1.12: System use notification

N

OPC does not define the how a client prompts for username/password.

NDR 1.13 – Access via untrusted networks

N

OPC does not define network hardware requirements. It can restrict communication to be between uniquely identified applications. (see CR 1.2)

NDR 1.13 RE (1) Explicit access request approval

N

Same as NDR 1.13 above

CR 1.14: Strength of symmetric key-based authentication

Y

OPC 10000-2

Symmetric Encryption

OPC 10000-6

SymmetricEncryptionAlgorithm

OPC 10000-7

Global Service Key Credential Pull/Push Facets, KeyCredential Service Server Facet, KeyCredential Service Client Facet

Part 14

SecuritKeyService (SKS), SymmetricEncryptionAlgorithm

CR 1.14 RE (1) Hardware security for symmetric key-based authentication

N

The OPC UA specification does not provide hardware requirements and does not utilize long lived symmetric keys

Table A.2 ISA/IEC 62443 mapping FR 2 Use control

ISA-62443-4-2

CRs and Res

Related to

Applies to OPC UA

OPC UA Part #

Keyword text or comment

SL1

SL2

SL3

SL4

CR 2.1: Authorization enforcement

Y

OPC 10000-2

UserAuthorization

OPC 10000-4

Authorization Services, IssuedIdentityToken

OPC 10000-6

AuthorizationService, JSON Web Token (JWT)

OPC 10000-7

User Token – JWT Server Facet, User Token – JWT Client Facet

RE (1): Authorization enforcement for all users (humans, software processes, and devices)

Y

OPC 10000-2

UserAuthorization

OPC 10000-4

Authorization Services, IssuedIdentityToken

OPC 10000-6

AuthorizationService, JSON Web Token (JWT)

OPC 10000-7

User Token – JWT Server Facet, User Token – JWT Client Facet

RE (2): Permission mapping to roles

Y

OPC 10000-2

Roles, JWT, and User Roles

OPC 10000-18

User Authorization, Role Type

OPC 10000-6

RolePermissions

OPC 10000-7

User Role Management Server/Client Facets

CR 2.1 RE (3) Supervisor override

P

OPC provides the ability to switch user context, but it does not provide an automatic timeout for a switch

OPC 10000-4

Authorization Services

CR 2.1 RE (4) Dual approval

N

OPC does not define the logic for applications and thus does not define dual approval

CR 2.2: Wireless use control

N

OPC is hardware agnostic.

CR 2.3 – Use control for portable and mobile devices

NA

NA

NA

NA

N

No component level requirements defined in 62443

SAR 2.4: Mobile code

N

OPC does not define Mobile code technologies

SAR 2.4 RE (1): Mobile code authenticity check

N

OPC does not define Mobile code technologies

EDR 2.4: Mobile code

N

OPC does not define Mobile code technologies

EDR 2RE (1): Mobile code authenticity check

N

OPC does not define Mobile code technologies

HDR 2.4: Mobile code

N

OPC does not define Mobile code technologies

HDR 2.4RE (1): Mobile code authenticity check

N

OPC does not define Mobile code technologies

NDR 2.4 – Mobile code

N

OPC does not define Mobile code technologies

NDR 2.4 – Mobile code

N

OPC does not define Mobile code technologies

CR 2.5: Session lock

N

OPC UA does not define human user interface

CR 2.6: Remote session termination

P

OPC allows identification of remote session via ApplicationAuthentication, remote restrictions are application specific, but the infrastructure is provided.

OPC 10000-4

IssuedIdentityToken

OPC 10000-6

JSON Web Token (JWT), JWT UserTokenPolicy

OPC 10000-7

Security User JWT IssuedToken, Security User JWT Token Policy, OPC UA Authority Profile

CR 2.7 – Concurrent session control

N

OPC provides limits on sessions, subscription and other functionality and defines behaviour if these limits are exceeded, but it does not provide limits per user.

CR 2.8: Auditable events

Y

OPC 10000-2

Auditability, Auditing, Audit Event Management

OPC 10000-4

Auditing

OPC 10000-5

AuditSecurityEventType

OPC 10000-7

Auditing Server Facet, Auditing Client Facet, Best Practice – Audit Events

CR 2.9: Audit storage capacity

N

OPC does not define Audit storage.

CR 2.9 RE (1) Warn when audit record storage capacity threshold reached.

N

OPC does not define Audit storage.

CR 2.10: Response to audit processing failures

N

OPC does not provide Audit storage

CR 2.11: Timestamps

Y

OPC 10000-2

Message replay, Timestamps, SecureChannelId

OPC 10000-4

TimestampsToReturn

OPC 10000-5

AuditEventType

OPC 10000-7

Auditing Server Facet

CR 2.11 RE (1): Time synchronization

Y

OPC 10000-2

Cryptographic Keys (time validity of security profile)

OPC 10000-4

SourceTimestamp, VersionTime, Redundant Server Set Requirements

OPC 10000-6

Time Synchronization

OPC 10000-7

Security Time Synchronization

CR 2.11 RE (2) Protection of time source integrity

N

OPC does not define a unique time synchronization scheme, but utilize other industry standard.

CR 2.12: Non-repudiation

Y

OPC 10000-2

Message alteration, Server Profiling, System Hijacking, Repudiation, Audit Event Management

OPC 10000-4

Signing, GetEndpoints, SecureChannel, Auditing, Proof of Possession,

OPC 10000-7

User Token – JWT Server/Client Facets, Auditing Server Facet, Auditing Client Facet, Best Practice – Audit Events

CR 2.12 RE (1) Non-repudiation for all users

Y

OPC 10000-2

Message alteration, Server Profiling, System Hijacking, Repudiation, Audit Event Management

OPC 10000-4

Signing, GetEndpoints, SecureChannel, Auditing, Proof of Possession,

OPC 10000-7

User Token – JWT Server/Client Facets, Auditing Server Facet, Auditing Client Facet, Best Practice – Audit Events

EDR 2.13: Use of physical diagnostic and test interfaces

N

OPC is hardware agnostic.

EDR 2.13 RE (1) Active monitoring

N

OPC is hardware agnostic

HDR 2.13: Use of physical diagnostic and test interfaces

N

OPC is hardware agnostic

HDR 2.13 RE (1) Active monitoring

N

OPC is hardware agnostic

NDR 2.13: Use of physical diagnostic and test interfaces

N

OPC is hardware agnostic

NDR 2.13 RE (1) Active monitoring

N

OPC is hardware agnostic

Table A.3 ISA/IEC 62443 Mapping FR 3 System integrity

ISA-62443-4-2

CRs and Res

Related to

Applies to OPC UA

OPC UA Part #

Keyword text or comment

SL1

SL2

SL3

SL4

CR 3.1: Communication integrity

Y

OPC 10000-2

SecureChannel – OpenSecureChannel

OPC 10000-4

SecureChannel Service Set

OPC 10000-6

SecureChannel, SecurityProtocol

OPC 10000-7

Security Policy Required, Security

Policy [A] & [B]

CR 3.1 RE (1): Communication authentication

Y

OPC 10000-2

SecureChannel – OpenSecureChannel

OPC 10000-4

SecureChannel Service Set

OPC 10000-6

SecureChannel

OPC 10000-7

Security Policy Required, Security

SAR 3.2: Protection from malicious code

N

OPC does not define requirement related to malicious code protection (for example. virus checkers)

EDR 3.2: Protection from malicious code

N

OPC does not define requirement related to installation or execution of software

HDR 3.2: Protection from malicious code

N

OPC does not define requirement related to malicious code protection (for example. virus checkers)

HDR 3.2 RE (1): Report version of code protection

N

OPC does not define requirement related to malicious code protection (for example. virus checkers)

NDR 3.2 – Protection from malicious code

N

OPC does not define requirement related to malicious code protection (for example. virus checkers)

CR 3.3: Security functionality verification

Y

OPC 10000-2

Identity Provider, SecurityKeyService, SecureChannel, TLS

OPC 10000-4

OpenSecureChannel, CreateSession, Write

OPC 10000-6

OPC UA Secure Conversation (UASC), Verifying Message Security, Token Policy, Bad_SecureChannel

OPC 10000-7

User Token – JWT Server/Client facets, Security Policy [A] & [B]

CR 3.3 RE (1) Security functionality verification during normal operation

N

OPC does not define security function verification

CR 3.4: Software and information integrity

P

OPC 10000-2

ApplicationInstance Security Certificate

OPC 10000-4

SoftwareCertificates

OPC 10000-6

ApplicationInstance Security Certificate, X.509 v3

OPC 10000-7

Security ApplicationInstance Security Certificate, Global Security Certificate Management Server/Client Profiles

CR 3.4 RE (1): Authenticity of software and information

P

OPC 10000-2

ApplicationInstance Security Certificate

OPC 10000-4

SoftwareCertificates

OPC 10000-6

ApplicationInstance Security Certificate, X.509 v3

OPC 10000-7

Security ApplicationInstance Security Certificate, Global Security Certificate Management Server/Client Profiles

CR 3.4 RE (2) Automated notification of integrity violations

P

OPC 10000-2

ApplicationInstance Security Certificate

OPC 10000-4

SoftwareCertificates

OPC 10000-6

ApplicationInstance Security Certificate, X.509 v3

OPC 10000-7

Security ApplicationInstance Security Certificate, Global Security Certificate Management Server/Client Profiles

CR 3.5: Input validation

N

OPC does not define HMI requirements, but does ensure that input data (method parameter or for write) is of the correct datatype

CR 3.6: Deterministic output

N

OPC does not define application behaviour, but does define information models that include substituted values and other behaviours for failed states.

CR 3.7: Error handling

Y

OPC 10000-4

Request/Response Service

OPC 10000-5

SessionDiagnosticsObjectType

OPC 10000-6

MessageChunks, Error Handling, Error Message, CloseSecureChannel

OPC 10000-7

Security Policy Required, Security Policy [A] & [B]

CR 3.8: Session integrity

Y

OPC 10000-2

SecureChannel, Session ID

OPC 10000-4

Session Service Set, Creating a Session, Auditing Session Service, SessionAuthenticationToken

OPC 10000-7

Session Services Facets, Standard UA Client 2017 Profile, Base Server Behavior Facet

CR 3.9: Protection of audit information

P

OPC provides security related to Audit event generation, but does not define Audit Logging requirements or tools for analysing audit records

OPC 10000-2

SecureChannel, Session ID

OPC 10000-4

Session Service Set, Creating a Session, Auditing Session Service, SessionAuthenticationToken

OPC 10000-7

Session Services Facets, Standard UA Client 2017 Profile, Base Server Behavior Facet

CR 3.9 RE (1) Audit records on write-once media

N

OPC does not define hardware requirements

EDR 3.10: Support for updates

N

Some companion specification can define additional functionality that would apply, such as OPC 10000-100

EDR 3.10: RE (1): Update authenticity and integrity

N

HDR 3.10: Support for updates

N

HDR 3.10 RE (1): Update authenticity and integrity

N

NDR 3.10 – Support for updates

N

NDR 3.10 RE (1) Update authenticity and integrity

N

EDR 3.11: Physical tamper resistance and detection

N

EDR 3.11 RE (1) Notification of a tampering attempt

N

HDR 3.11: Physical tamper resistance and detection

N

HDR 3.11 RE (1) Notification of a tampering attempt

N

NDR 3.11 – Physical tamper resistance and detection

N

NDR 3.11 RE (1) Notification of a tampering attempt

N

EDR 3.12: Provisioning product supplier roots of trust

N

HDR 3.12: Provisioning product supplier roots of trust

N

NDR 3.12 – Provisioning product supplier roots of trust

N

EDR 3.13: Provisioning asset owner roots of trust

N

HDR 3.13: Provisioning asset owner roots of trust

N

NDR 3.13 – Provisioning asset owner roots of trust

N

EDR 3.14: Integrity of the boot process

N

EDR 3.14 RE (1): Authenticity of the boot process

N

HDR 3.14: Integrity of the boot process

N

HDR 3.4 RE (1): Authenticity of the boot process

N

NDR 3.14 – Integrity of the boot process

N

NDR 3.14 RE (1) Authenticity of the boot process

N

Table A.4 ISA/IEC 62443 Mapping FR 4 Data confidentiality

ISA-62443-4-2

CRs and Res

Related to

Applies to OPC UA

OPC UA Part #

Keyword text or comment

SL1

SL2

SL3

SL4

CR 4.1: Information confidentiality

Y

OPC 10000-2

Confidentiality, Confidentiality, Eavesdropping, Client/Server, PubSub, Confidentiality

OPC 10000-4

SecureChannel Service Set

OPC 10000-6

OPC UA HTTPS, WebSockets (Security)

OPC 10000-7

Security Policy Required, Security Policy [A] & [B]

CR 4.2: Information persistence

N

OPC does not describe hardware

CR 4.2 RE (1) Erase of shared memory resources

N

OPC does not describe hardware

CR 4.2 RE (2) Erase verification

N

OPC does not describe hardware

CR 4.3: Use of cryptography

Y

OPC 10000-2

Asymmetric Cryptography, Cryptography, Symmetric Cryptography, SecurityPolicies, Random Number Generation, Security Certificate Management

OPC 10000-4

GetEndpoints, OpenSecureChannel

OPC 10000-6

Security Handshake, Security Certificates, AccessTokens, Security Header, Deriving Keys (Table 49)

OPC 10000-7

AccessToken Request Client Facet, Security User Access Control Base Profile, Best Practice – Random Numbers, Global Discovery and Security Certificate Management 2017 Server, Global Security Certificate Management Client 2017 Profile

OPC 10000-12

Certificate Management Overview, KeyCredential Management

Table A.5 ISA/IEC 62443 Mapping FR 5 Restricted data flow

ISA-62443-4-2

CRs and Res

Related to

Applies to OPC UA

OPC UA Part #

Keyword text or comment

SL1

SL2

SL3

SL4

CR 5.1: Network segmentation

Y

OPC 10000-2

Network Segmentation, OpenSecureChannel

OPC 10000-7

Standard UA Client 2017 Profile, Base Server Behavior Facet

NDR 5.2 – Zone boundary protection

N

OPC does not define network hardware.

NDR 5.2 RE (1) Deny all, permit by exception

N

OPC does not define network hardware.

NDR 5.2 RE (2) Island mode

N

OPC does not define network hardware.

NDR 5.2 RE (3) Fail close

N

OPC does not define network hardware.

NDR 5.3 – General purpose, person-to-person communication restrictions

N

OPC does not define network hardware.

CR 5.4 – Application partitioning

NA

NA

NA

NA

NA

Nothing defined in IEC62443

Table A.6 ISA/IEC 62443 Mapping FR 6 Timely response to events

ISA-62443-4-2

CRs and Res

Related to

Applies to OPC UA

OPC UA Part #

Keyword text or comment

SL1

SL2

SL3

SL4

CR 6.1: Audit log accessibility

N

OPC does not define an Audit log. OPC defines standard Audit records and also defined historical storage of events. It provides access restriction for all data.

CR 6.1 RE (1) Programmatic access to audit logs

N

OPC Does not define an Audit log. OPC defines standard Audit records and also defined historical storage of events. It provides access restriction for all data, standard methods for programmatical access are defined.

CR 6.2: Continuous monitoring

Y

OPC 10000-7

Monitor Items, GetMonitoredItems Method, SetMonitoringMode. Subscription Server Facet, Standard UA Client 2017 Profile, Standard DataChange Subscription 2017 Server Facet

Table A.7 ISA/IEC 62443 Mapping FR 7 Resource availability

ISA-62443-4-2

CRs and REs

Related to

Applies to OPC UA

OPC UA Part #

Keyword text or comment

SL1

SL2

SL3

SL4

CR 7.1: Denial of service protection

Y

OPC 10000-2

Application Crashes, Fuzz Testing, Certification

OPC 10000-4

CreateSession, OpenSecureChannel, AuthenticationToken

OPC 10000-7

Session Services Facets, Standard UA Client 2017 Profile, Base Server Behavior Facet

CR 7.1 RE (1): Manage communication load from component

Y

OPC 10000-2

Message flooding, GetEndpoints, OpenSecureChannel

OPC 10000-4

CreateSession, OpenSecureChannel, AuthenticationToken

OPC 10000-7

Session Services Facets, Standard UA Client 2017 Profile, Base Server Behavior Facet

CR 7.2: Resource management

Y

OPC 10000-2

Resource exhaustion, ClientAuthentication, ServerAuditing, OpenSecureChannel

OPC 10000-4

CreateSession, OpenSecureChannel, AuthenticationToken

OPC 10000-7

Session Services Facets, Standard UA Client 2017 Profile, Base Server Behavior Facet

CR 7.3: Control system backup

N

OPC does not define system level backup requirements.

CR 7.3 RE (1): Backup integrity verification

N

OPC does not define verification of backup requirements.

CR 7.4: Control system recovery and reconstitution

N

OPC UA does not define backup and restore requirements (to a specific state).

CR 7.5 - Emergency Power

NA

NA

NA

NA

NA

(no requirements for this)

CR 7.6: Network and security configuration settings

P

OPC UA requires that application can be configured for network and security setting, but it does not define how this is accomplished.

OPC 10000-2

ClientAuthentication, OpenSecureChannel

OPC 10000-4

CreateSession, OpenSecureChannel, Discovery

OPC 10000-7

Session Services Facets, Standard UA Client 2017 Profile, B

CR 7.6 RE (1) Machine-readable reporting of current security settings

P

This is not defined in an OPA UA specification, but OPC UA does define a machine readable XML format that an application could be used to export the security setting.

OPC 10000-2

ClientAuthentication, OpenSecureChannel

OPC 10000-4

CreateSession, OpenSecureChannel, Discovery

OPC 10000-7

Session Services Facets, Standard UA Client 2017 Profile

CR 7.7: Least functionality

N

OPC 10000-2

The OPC UA specification does describe that least functionality is recommended with regard to OPC UA access, but this requirement applies to all service/ports protocols, etc. which is beyond the scope of OPC UA Specifications.

CR 7.8: Control system component inventory

N

This scope is beyond what is defined in core OPC UA specifications. Some companion specification can define additional details about the overall environment in which OPC UA is executing, which could be able to cover this requirement.

The Open Group has given the OPC Foundation permission to incorporate the above table(s) from their copyrighted documentation: O-PAS™ Standard, Version 2.1, Copyright© 2021 The Open Group. The table has been edited in this version for content, format and structure.