Model File Format

See also

The Xentara Model File in the Xentara user manual

A JSON object describing OPC UA Client has the following syntax:

{
  "@Skill.OPCUAClient.Connection": {
    "name": "Connection",
    "UUID": "c9764682-c529-4650-b5df-b8273d83969d",
    "URL": "opc.tcp://hostname:4840",
    "applicationURI": "urn:hostname:Xentara%20Client",
    "userName": "...",
    "password": "...",
    "serverCertificate": "/path/to/certificate",
    "clientCertificate": { "..." },
    "userAuthenticationSecurityPolicy": "SignAndEncrypt",
    "securityMode": "SignAndEncrypt",
    "securityPolicy": "Aes128_Sha256_RsaOaep",
    "publishRequests": 100,
    "children": [
      {
        "@Skill.OPCUAClient.Node": {
          "name": "Node",
          "UUID": "3eaea0b9-610e-4064-adf0-432f41ec148d",
          "nodeId": "ns=1;g=86865b3d-4c41-4a8b-8b78-f2d4ddb09b6f",
          "dataType": "Int32",
          "accessLevel": [
            "Read"
          ],
          "samplingInterval": 250
        }
      },
      {
        "@Skill.OPCUAClient.ArrayNode": {
          "name": "Array Node",
          "UUID": "de0c545d-cfa7-4e6e-acfb-e20a9b976e6d",
          "nodeId": "ns=0;i=2269",
          "dataType": "String",
          "samplingInterval": 250,
          "arraySize": 3
        }
      }
    ]
  }
}

Connection members

name	A string value containing the name of the connection. The name is used to construct the connection’s primary key.
UUID	A string value containing the unique UUID of the connection.
ACL	An optional JSON object containing the element ACL of the connection. The format of the object is described under JSON Format for ACLs in the Xentara user manual.
URL	A string value containing the URL to the the OPC UA Server.
applicationURI	An optional string value containing the application URI. The default value is automatically generated based on the following pattern: urn:{fully-qualified-host-name}:{uri-encoded-opcua-server-instance-primary-key}.
userName	An optional username if the OPC UA server supports the “UserName” token type.
password	An optional password if the OPC UA server supports the “UserName” token type.
serverCertificate	An optional JSON object containing the path to the OPC UA server instance certificate. The field is required when the certificate is self-signed and can be omitted if the certificate is signed by trusted CA or the server has no certificate (server Security Mode is None)
clientCertificate	An optional JSON object containing the path to the OPC UA server instance certificate. The field is required when the certificate is self-signed and can be omitted if the certificate is signed by trusted CA or the server has no certificate (server Security Mode is None). The format of the object is described under JSON Format for Certificates in the Xentara user manual.
userAuthenticationSecurityPolicy	An optional security policy to include in the use authentication token when sending the certificate. The user certificate must conform to the security requirements of this policy. Possible values are described under Security Policies.
securityMode	An optional Security Mode the endpoint will use. Xentara will refuse to connect to the server if it doesn’t offer any endpoints with the given security mode. By default all security modes are allowable, including “None”.
securityPolicy	An optional security policy the endpoint must use. Xentara will refuse to connect to the server if it doesn’t offer any endpoints with the given security policy. By default all security policies are allowable, including “None”. Possible values are described under Security Policies.
publishRequests	The maximum number of simultaneous publish requests to send to the server, see UA_ClientConfig.outStandingPublishRequests. Defaults to 10.
children	A JSON Array of OPC UA Nodes at the server, to which the client subscribes.

A JSON object describing OPC UA Node the following syntax:

Node members

name	A string value containing the name of the node. The name is used to construct the node’s primary key.
UUID	A string value containing the unique UUID of the node.
ACL	An optional JSON object containing the element ACL of the node. The format of the object is described under JSON Format for ACLs in the Xentara user manual.
nodeId	OPC UAs internal namespace index and identifier type in format: ns=<namespaceIndex>;<identifiertype>=<identifier>
dataType	One of the OPC UA numerical Datatypes Sbyte, Byte, Int16, Uint16, Int32, Uint32, Int64, Uint64, Float, Double, Bool, String, TimeStamp, UUID
samplingInterval	An optional sampling interval for the node value. Defaults to 250ms.
accessLevel	Array of access levels for the node. The accepted elements are "Read" and "Write".

A JSON object describing a read-only OPC UA Array Node the following syntax:

Array Node members

name	A string value containing the name of the array node. The name is used to construct the array node’s primary key.
UUID	A string value containing the unique UUID of the array node.
ACL	An optional JSON object containing the element ACL of the array node. The format of the object is described under JSON Format for ACLs in the Xentara user manual.
nodeId	OPC UAs internal namespace index and identifier type in format: ns=<namespaceIndex>;<identifiertype>=<identifier>
dataType	One of the OPC UA numerical Datatypes Sbyte, Byte, Int16, Uint16, Int32, Uint32, Int64, Uint64, Float, Double, Bool, String, TimeStamp, UUID
samplingInterval	An optional sampling interval for the node value. Defaults to 250ms.
arraySize	Number of the elements in the array.

Security Policies

Security Policy	Description
“None”	Adds the channel policy of None. If no user-token-policy is specified, it defaults to None
“Basic256”	Adds the channel policy and the user token policy of Basic256
“Basic128Rsa15”	Adds the channel policy and the user token policy of Basic128Rsa15
“Basic256Sha256”	Adds the channel policy and the user token policy of Basic256Sha256
“Aes256_Sha256_RsaPss”	Adds the channel policy and the user token policy of Aes256_Sha256_RsaPss
“Aes128_Sha256_RsaOaep”	Adds the channel policy and the user token policy of Aes128_Sha256_RsaOaep

Warning

The security policies “Basic256” and “Basic128Rsa15” are deprecated due to known vulnerabilities. Their use introduces significant security risks and is strongly discouraged, especially in production environments.

Warning

Communication channels established using the “None” security policy are not encrypted. This exposes data to potential interception or tampering and poses serious security risks. Use of this policy is strongly discouraged in production environments.