OPC UA® monitored item and subscription An OPC UA® client can subscribe to a list of variables that are then monitored for changes by the GDS. The variables are checked for changes at a defined interval. When subscribing to a variable, the client can define a sample rate, which is then served by… Read More
OPC UA session Creation The eUA server supports a limited amount of concurrent sessions depending on the controller type (Device-specific OPC UA settings). The server verifies the ClientCertificate for secure endpoints when creating a session. Make sure that the ApplicationURI specified in the ApplicationDescription matches the… Read More
Reverse Connect Available from firmware version 2022.9 What problem should be solved In some automation applications the PLCnext Control device is connected to the internet. In this case, a basic security requirement is to reduce the open ports to prevent attacks from the internet. The Reverse Connect… Read More
OPC UA client Available from 2023.0 LTS The OPC UA client supports subscribing variables from connected servers and writing changes of local variables to connected servers. The PLCnext Control device establishes the connection automatically as soon as the server is available. When the connection gets lost, the OPC UA… Read More
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. … Read More
Global Data Space The GlobalDataSpace namespace All programs and variables from the IEC 61131 context are displayed in the http://phoenixcontact.com/OpcUA/PLCnext/GlobalDataSpace/ namespace. Via the namespace, the corresponding NamespaceIndex can be determined from the NamespaceArray. The NamespaceIndex is a numeric value for identification of the namespace. It is saved in the… Read More
Profile and facets The eUA Server implements the Embedded 2017 UA Server Profile and supports the following facets: Facets: Global Certificate Management Server Facet Historical Raw Data Server Facet A & C Alarm Server Facet File Access Server Facet DI BaseDevice… Read More
Adding External Information Models In this topic, we describe the features that allow the integration of external information models into the embedded OPC UA server of PLCnext: First, the storage of the required NodeSet.xml files is described Then the instance NodeSet.xml as a special form is explained. We show how… Read More
Connection configuration Note: The OPC UA client and server use the OpenSSL library to validate X.509 certificates using the OpenSSL flag X509_V_FLAG_X509_STRICT. As firmware 2024.0 LTS is updated to OpenSSL 3.0, the X.509 certificate validation became more strict, especially for non self-signed certificates. This may cause the server to return the… Read More
OPC UA Services The eUA Server provides these IEC 62541-4 compliant services to client applications: Discovery Secure channel Session Monitored item and subscription Reverse Connect (from firmware 2022.9 or newer) Firmware Update with OPC UA (from firmware 2022.0 LTS or newer) • Published/reviewed: 2025-08-22 ❁ Revision 083 • … Read More
