OPC UA client XML schema

Schema file

The connection configuration is defined in XML files. It is based on the standard UA schema for data types which can be found here.

It is formally defined in this schemathis schema.

<xs:schema elementFormDefault="qualified" targetNamespace="http://phoenixcontact.com/OpcUA/PLCnext/UAClientConfig/Types.xsd" 
xmlns:tns="http://phoenixcontact.com/OpcUA/PLCnext/UAClientConfig/Types.xsd" 
xmlns:ua="http://opcfoundation.org/UA/2008/02/Types.xsd" xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:import namespace="http://opcfoundation.org/UA/2008/02/Types.xsd"/>
    <xs:simpleType name="eUAClientGroupType">
        <xs:restriction base="xs:string">
            <xs:enumeration value="Subscribe_0"/>
             <xs:enumeration value="Write_1"/>
        </xs:restriction>
    </xs:simpleType>
    <xs:element type="tns:eUAClientGroupType" name="eUAClientGroupType"/>
    <xs:complexType name="ListOfeUAClientGroupType">
        <xs:sequence>
            <xs:element minOccurs="0" maxOccurs="unbounded" type="tns:eUAClientGroupType" name="eUAClientGroupType" nillable="true"/>
        </xs:sequence>
    </xs:complexType>
    <xs:element type="tns:ListOfeUAClientGroupType" name="ListOfeUAClientGroupType" nillable="true"/>
    <xs:complexType name="eUAClientConfiguration">
        <xs:sequence>
            <xs:element minOccurs="0" maxOccurs="1" type="xs:string" name="Name"/>
            <xs:element minOccurs="0" maxOccurs="1" type="ua:ListOfString" name="NamespaceArray"/>
            <xs:element minOccurs="0" maxOccurs="1" type="tns:ListOfeUAClientServerConnection" name="ServerConnections"/>
            <xs:element minOccurs="0" maxOccurs="1" type="tns:ListOfeUAClientVariableGroup" name="VariableGroups"/>
        </xs:sequence>
    </xs:complexType>
    <xs:element type="tns:eUAClientConfiguration" name="eUAClientConfiguration"/>
    <xs:complexType name="ListOfeUAClientConfiguration">
        <xs:sequence>
            <xs:element minOccurs="0" maxOccurs="unbounded" type="tns:eUAClientConfiguration" name="eUAClientConfiguration" nillable="true"/>
        </xs:sequence>
    </xs:complexType>
    <xs:element type="tns:ListOfeUAClientConfiguration" name="ListOfeUAClientConfiguration" nillable="true"/>
    <xs:complexType name="eUAClientNodeMapping">
        <xs:sequence>
            <xs:element minOccurs="0" maxOccurs="1" type="ua:NodeId" name="LocalVariable"/>
            <xs:element minOccurs="0" maxOccurs="1" type="tns:eUAClientRemoteVariableDescriptor" name="RemoteVariableDescriptor"/>
        </xs:sequence>
    </xs:complexType>
    <xs:element type="tns:eUAClientNodeMapping" name="eUAClientNodeMapping"/>
    <xs:complexType name="ListOfeUAClientNodeMapping">
        <xs:sequence>
            <xs:element minOccurs="0" maxOccurs="unbounded" type="tns:eUAClientNodeMapping" name="eUAClientNodeMapping" nillable="true"/>
        </xs:sequence>
    </xs:complexType>
    <xs:element type="tns:ListOfeUAClientNodeMapping" name="ListOfeUAClientNodeMapping" nillable="true"/>
    <xs:complexType name="eUAClientRemoteVariableDescriptor">
        <xs:sequence>
            <xs:element minOccurs="0" type="xs:unsignedInt" name="EncodingMask"/>
            <xs:element minOccurs="0" maxOccurs="1" type="xs:string" name="DiscoveryEndpoint"/>
            <xs:element minOccurs="0" maxOccurs="1" type="xs:short" name="ServerIndex"/>
            <xs:element minOccurs="0" maxOccurs="1" type="ua:NodeId" name="NodeId"/>
            <xs:element minOccurs="0" maxOccurs="1" type="xs:string" name="AliasName"/>
            <xs:element minOccurs="0" maxOccurs="1" type="ua:NodeId" name="AliasReferenceTypeFilter"/>
            <xs:element minOccurs="0" maxOccurs="1" type="ua:ListOfRelativePathElement" name="BrowsePath"/>
        </xs:sequence>
    </xs:complexType>
    <xs:element type="tns:eUAClientRemoteVariableDescriptor" name="eUAClientRemoteVariableDescriptor"/>
    <xs:complexType name="ListOfeUAClientRemoteVariableDescriptor">
        <xs:sequence>
            <xs:element minOccurs="0" maxOccurs="unbounded" type="tns:eUAClientRemoteVariableDescriptor" name="eUAClientRemoteVariableDescriptor" nillable="true"/>
        </xs:sequence>
    </xs:complexType>
    <xs:element type="tns:ListOfeUAClientRemoteVariableDescriptor" name="ListOfeUAClientRemoteVariableDescriptor" nillable="true"/>
    <xs:complexType name="eUAClientServerConnection">
        <xs:sequence>
            <xs:element minOccurs="0" type="xs:unsignedInt" name="EncodingMask"/>
            <xs:element minOccurs="0" maxOccurs="1" type="ua:EndpointType" name="Endpoint"/>
            <xs:element minOccurs="0" maxOccurs="1" type="ua:UserTokenType" name="UserTokenType"/>
            <xs:element minOccurs="0" maxOccurs="1" type="xs:string" name="UserName"/>
            <xs:element minOccurs="0" maxOccurs="1" type="xs:string" name="Password"/>
            <xs:element minOccurs="0" maxOccurs="1" type="xs:base64Binary" name="CertificateData"/>
            <xs:element minOccurs="0" maxOccurs="1" type="xs:base64Binary" name="TokenData"/>
        </xs:sequence>
    </xs:complexType>
    <xs:element type="tns:eUAClientServerConnection" name="eUAClientServerConnection"/>
    <xs:complexType name="ListOfeUAClientServerConnection">
        <xs:sequence>
            <xs:element minOccurs="0" maxOccurs="unbounded" type="tns:eUAClientServerConnection" name="eUAClientServerConnection" nillable="true"/>
        </xs:sequence>
    </xs:complexType>
    <xs:element type="tns:ListOfeUAClientServerConnection" name="ListOfeUAClientServerConnection" nillable="true"/>
    <xs:complexType name="eUAClientVariableGroup">
        <xs:sequence>
            <xs:element minOccurs="0" maxOccurs="1" type="tns:eUAClientGroupType" name="GroupType"/>
            <xs:element minOccurs="0" maxOccurs="1" type="xs:double" name="CycleTime"/>
            <xs:element minOccurs="0" maxOccurs="1" type="tns:ListOfeUAClientNodeMapping" name="NodeMappings"/>
        </xs:sequence>
    </xs:complexType>
    <xs:element type="tns:eUAClientVariableGroup" name="eUAClientVariableGroup"/>
    <xs:complexType name="ListOfeUAClientVariableGroup">
        <xs:sequence>
            <xs:element minOccurs="0" maxOccurs="unbounded" type="tns:eUAClientVariableGroup" name="eUAClientVariableGroup" nillable="true"/>
        </xs:sequence>
    </xs:complexType>
    <xs:element type="tns:ListOfeUAClientVariableGroup" name="ListOfeUAClientVariableGroup" nillable="true"/>
</xs:schema>

Schema documentation

The OPC UA client configuration is based on OPC UA data type definitions. It also references some well-known data types form the OPC UA specification (like NodeId or UserTokenType). The description of these data types can be found in the official OPC UA reference.

Namespace handling

Namespace indices are used instead of namespaces at different places within the XML file. These indices refer to the common namespace table at the top of the XML file.

Note: Maintain all used namespaces in the namespace table. Do not copy the namespace indices from tools like UA Expert (the namespace index of OPC UA server is only valid during a session).

eUAClientConfiguration

eUAClientConfiguration is a subtype of Structure.

Attribute	Data type	Description
`Name`	`String`	Name of the configuration (not evaluated by the runtime).
`NamespaceArray`	`String`	List of namespaces used within the client configuration document. All namespace indices are referring to this list.
`ServerConnections`	`eUAClientServerConnection`	Array of servers that are used in this configuration document. All server indices are pointing to this list (the first entry has index `1`).
`VariableGroups`	`eUAClientVariableGroup`	Groups of variables that are either subscribed or written to other servers.

eUAClientServerConnection

eUAClientServerConnection is a subtype of Structure.

Attribute	Data type	Description
`Endpoint`	`EndpointType`	Endpoint with `Url`, `SecurityPolicy` and `SecurityMode`. Note: If the `SecurityPolicy` is omitted, the client chooses `best available`.
`UserTokenType`	`UserTokenType`	`UserIdentityToken` that is used to authenticate to the server. (not used - leave empty)
`UserName`	`StringUserName`	`UserName` that is used for `UserTokenType` `UserNameIdentityToken`.
`Password`	`String`	Password that is used for `UserTokenType` `UserNameIdentityToken`.
`CertificateData`	`ByteString`	Certificate that is used for `UserTokenType` `X509IdentityToken`. (not used - leave empty)
`TokenData`	`ByteString`	`TokenData` that is used for `UserTokenType` `IssuedIdentityToken`. (not used - leave empty)

eUAClientVariableGroup

eUAClientVariableGroup is a subtype of Structure.

Attribute	Data type	Description
`GroupType`	`eUAClientGroupType`	Type of variable group (e.g. subscribe or write).
`CycleTime`	`Duration`	Desired update interval to observe the variables. Variables are only synchronized when the value of the variables changes.
`NodeMappings`	`eUAClientNodeMapping`	List of mappings with local and remote variables.

eUAClientGroupType

eUAClientGroupType is a subtype of Enumeration.

Attribute	Description
`Subscribe_0`	Subscribe to the variables of the remote OPC UA server.
`Write_1`	Write changed values of local variables to variables of the remote OPC UA server.

eUAClientNodeMapping

eUAClientNodeMapping is a subtype of Structure.

Attribute	Data type	Description
`LocalVariable`	`NodeId`	`NodeId` of a variable of the local OPC UA server.
`RemoteVariableDescriptor`	`eUAClientRemoteVariableDescriptor`	Information how to find a node on a remote OPC UA server.

eUAClientRemoteVariableDescriptor

eUAClientRemoteVariableDescriptor is a subtype of Structure.

Attribute	Data type	Description
`DiscoveryEndpoint`	`String`	The discovery endpoint URL of the OPC UA server containing the desired node or of the discovery server to begin the search. `DiscoveryEndpoint` allows access to discovery services without a session and without message security. (not used - leave empty)
`ServerIndex`	`Int16`	`1` based index into the servers array of the `eUAClientConfiguration`. If the `ServerIndex` is set to `-1`, it is expected that the `DiscoveryEndpoint` is that of a single server that contains the desired node (`0` is invalid).
`NodeId`	`NodeId`	The root node from which the `BrowsePath` is followed. If `NodeId` is present but the `DiscoveryEndpoint` and `ServerURI` are omitted, the `NodeId` is presumed to be local to the device.
`AliasName`	`String`	An alternate way to specify the root node. If `ServerURI` is present, only that specific server will be used to find the alias. (not used - leave empty)
`AliasReferenceTypeFilter`	`NodeId`	Optional filter for the `FindAlias` method. Used if the `AliasName` is specified. (not used - leave empty)
`BrowsePath`	`RelativePathElement BrowsePath`	`BrowsePath` which uses the `NodeId` as starting point. (not used - leave empty)

EndpointType

EndpointType is a subtype of Structure. See also OPC UA client security

Attribute	Data type	Description
`endpointUrl`	`String`	The URL for the `Endpoint` (e.g. `opc.tcp://192.168.1.10:4840`).
`securityMode`	`MessageSecurityMode`	The type of message security.
`securityPolicyUri`	`String`	The URI of the `SecurityPolicy`.
`transportProfileUri`	`String`	The URI of the `transportProfile`. (not used - leave empty)

Note: If the SecurityPolicy is omitted, the client chooses best available.

MessageSecurityMode

Security mode for messages between client and server.

Attribute	Description
`None_1`	No protection of messages.
`Sign_2`	Messages are signed.
`SignAndEncrypt_3`	Messages are signed and encrypted.

NodeId

A NodeId is encoded as a string with the following syntax:

ns=<namespaceindex>;<type>=<value>

<namespaceindex> refers to the NamespaceArray of the eUAClientConfiguration (ns=1 is the first entry).
<type> can be one of the following characters:
- i for numeric identifiers
- s for string identifiers
- g for guid identifiers
- b for binary identifiers
<value> is the identifier value encoded as string.

Examples

ns=1;s=Arp.Plc.Eclr/GlobalPlcVariable
ns=1;s=Arp.Plc.Eclr/ProgramInstanceName.FBInstanceName.LocalPlcVariable
ns=3;g=09087e75-8e5e-499b-954f-f2a9603db28a
ns=4;b=M/RbKBsRVkePCePcx24oRA==

• Published/reviewed: 2024-10-30 ☀ Revision 074 •