Overview of OPC UA protocol

OPC UA data parameter

The following image shows the data source input window for the OPC UA protocol:

121337224971.png

For the OPCUA protocol, the data source input supports the following parameters:

Parameter

Description

Protocol

Shows the selected protocol type.

Name

Name of the data source.

Description

Add a description for data source.

Reading Cycle

Enter a reading cycle for the data source.

OPC UA Server Name

Enter the name of the OPC UA Server Name.

OPC UA Server IP Address

Enter the OPC UA Server IP Address.

OPC UA Authentication Type

You can choose between the following types:

  • NONE: No authentication enabled.

  • BASIC: Enables the OPC UA BASIC authentication.

OPC UA Security Mode

You can choose between the following modes:

  • NONE: No security mode

  • CERTIFICATE: Enables to upload a certificate in the following formats: *.pfx, *.pf12, *.cer, *.crt, *.der, *.p7b, *.p7r, *.spc

OPC UA Data Access Specification

OPC UA Data Access Specification does not specify a certain representation for OPC UA Addresses (NodeId). A NodeId is represented by a combination of:

  • NamespaceIndex

  • IdentifierType

  • Identifier

OPC UA Client Driver addresses have the following syntax: ns=;=.

NOTE

OPC browsing is not supported.

For more information refer to the table below:

Field

Description

NamespaceIndex

The index of the OPC UA Server namespace in which the address resides. If the index is 0, the entire ns=;= clause is omitted.

IdentifierType

The type of address. OPC UA supports the following four address types:

i

A numeric address represented with 32-bit unsigned integer

s

A string address containing characters that can be encoded using UTF-8

g

A GUID address in the format of XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX

b

An opaque address (such as a byte string)

Identifier

The address that is formatted as a string. This address may be numeric, string, GUID, or opaque.

Examples NodeId

Below you can see examples of an OPC UA Addresses (NodeId) representation:

String

String IdentifierType

Example

ns=[id];s=[string]

ns=5;s=Counter1

Attribute NodeId

Value NodeId

NamespaceIndex

5

IdentifierType

String

Identifier

Counter1

NOTE

String for Identifier

The string you enter at the four Identifier will be case sensitive.

Numeric

Numeric IdentifierType

Example

ns=[id];i=[number]

ns=0;i=3190 OR

Attribute NodeId

Value NodeId

NamespaceIndex

0

IdentifierType

Numeric

Identifier

3190 [BaseEventType_LocalTime]

Guid

Guid IdentifierType

Example

ns=[id];g=[guid]

ns=1;g=0d4e10fa-b9e1-4842-bca6-887c7d8c31f0

Base64(Opaque)

Base64(Opaque) IdentifierType

Example

ns=[id];b=[base64]

ns=2;b=M/RbKBsRVkePCePcx24oRA==

Datatypes Conversion

The following table shows the Datatype Conversion:

IEC61131 elementary datatypes

OPC UA built-in datatypes

MindSphere Type

BOOL

Boolean

boolean

SINT

SByte

int

USINT

Byte

int

INT

Int16

int

UINT

UInt16

int

DINT

Int32

int

UDINT

UInt32

int

LINT

Int64

long

ULINT

UInt64

long

BYTE

Byte

int

WORD

UInt16

int

DWORD

UInt32

int

LWORD

UInt64

long

REAL

Float

double

LREAL

Double

double

STRING

String

string

CHAR

Byte

int

WSTRING

String

string

WCHAR

UInt16

int

DT
DATE_AND_TIME

DateTime

n/a

DATE

DateTime

n/a

TOD
TIME_OF_DAY

DateTime

n/a

TIME

Double

double

NOTE

“NodeID“ is not a valid part of the OPC string anymore.