> For the complete documentation index, see [llms.txt](https://docs.videc.de/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.videc.de/acron-9.3/en/anlagenkonfiguration/prozessanbindung/provider/providerid/treiberauswahl/opc_unified-architecture-client.md). # OPC Unified Architecture Client #### Background The OPC UA interface driver works with all OPC UA servers as from OPC UA version 1.0. Measurement data and service data can be imported. Alerts and messages cannot be imported at present. The ACRON Provider is notified of all changes to the requested data in event-controlled mode and saves them cyclically to the ACRON database. The OPCClientUA driver imports all the values of the server in event-controlled mode and sets its own time stamp. This enables ACRON Delta Event recording to be used. Note If the value of the tag is equal to ZERO, for import of the service processing pulses ACRON assumes that the unit in question is not running. If the value is any other, ACRON assumes that the unit is running. #### Configuring security and encryption for OPC UA * Before configuring, delete the outdated paths and files. To do so, in the plant path and on the computer on which you want the Provider to run, under C:\ProgramData\ACRON\PlantCache\plantid delete the `OPCUAClientConfig_1.ini` file and the complete `Certificates` subfolder. * For the Designer to be able to use the security settings for browsing the tags and the Provider to query data, the settings must be configured in the same way at two locations: * Start Designer and set up Provider with OPC Unified Architecture driver. * Select the Import/External variables from control system function, which will probably terminate with an error. * But as a result the file `OPCUAClientConfig_1.ini` has been created in the plant path and the subfolder `Certificates` has been created. * Then open the `OPCUAClientConfig_1.ini` file in the editor and initially change only the `SecurityMode` and `SecurityPolicy` entries as you want. * Then save the server certificate from the OPC server to the `Certificates` subfolder with the name `Server_Cert_1.der`. * Then in the Designer select the Import/External variables from control system function again. * If an error occurs again, you might need to approve the Designer as trusted in the OPC server configuration. * When you have finished configuring the Designer, and have created at least one external variable for measured value recording, repeat the whole operation with the Provider. * For this, use the path C:\ProgramData\ACRON\PlantCache\plantid on the computer on which you want the Provider to run. * Any further settings in the `OPCUAClientConfig_1.ini` file should only be made by OPC-UA experts. #### Syntax of external variable The variable name is composed of the prefix S, the symbolic namespace index, and the name from the OPC server, e.g. S3\_Temperature. Variables with numeric IDs are identified by a hash symbol '#', e.g. S3\_#7863#. The description of the external variable is populated with the namespace name when applied, e.g. . Each time the Provider reconnects to the OPC server the assignment of the namespace names to the namespace indices is reconstructed based on the stored symbolic indices. This means the namespace indices are easy to change through the server. This assignment is defined in the OPCUAClientConfig\_X.ini file when applying the external variable. To ensure that the configuration file OPCUAClientConfig\_X.ini is stored on the server, the external variable should also be applied in the Designer on the ACRON server. Note If you only want to import a single bit from an external variable, place a comma after the variable name and then append the bit number (0-31). To import the values of the 0th bit of the variable `TEST`, enter the external variable as follows: `TEST,0`. #### Import external variables 1. Set all parameters for the Provider 2. Start the control system 3. Run "Import from control system" in the "External variables" area Select the variables you want to import into ACRON. ## Driver ### Driver file Display the name of the selected driver and select a driver from the list of installed drivers ### Version Version of the driver file ### Interface type Display the driver interface type ### Data transfer type Description of the data transfer type ## Driver parameters ### Server URL Address of OPC UA Server; specified by the server installation. ### User Password (optional) User name and password if the server does not want an anonymous connection. Separate entries by blanks. ### OPC UA sampling interval in milliseconds ACRON relays this entry to the server. This determines how often as a maximum ACRON is notified by the server of value changes. So if 1000 milliseconds is entered the Provider is notified of value changes a maximum of once per second. If you enter 0 here, all value changes will be notified to the Provider. The system load is essentially determined by the server. So you need to find a compromise between granularity of data recording and system load. ### Browse Filter If the OPC UA Server applies the variable definitions in ACRON Designer, all the variables provided by the server - including those that are rarely useful for recording - will be included. If you specify a server vendor-specific filter, only the variables actually useful for data recording will be displayed for import. So this parameter has no influence on the Provider's data recording, only on the configuration in the Designer, and it can be changed at any time. If anything other than AT is specified as the browse filter, then the expression is interpreted as a group filter. The group levels has to be separated with the character |: In the following example, only variables from the Objects Server subgroup are listed: ![](/files/x5c3pZ5Jg5BiLYIxqOGC) ## Settings ### Polling delay after start Start of data logging in seconds after the ACRON Provider has successfully established process communication. This is useful, for example, if the opposite party takes some time after a restart to initialize all the variables. Recommended entry: Depending on the startup duration of the OPC UA Server, about 10 seconds ### Always display provider window on top Provider windows are always displayed on top ### Activate test mode Display a window with diagnostic messages On startup the ACRON Provider opens a window with diagnostic messages. The log file is stored under the relevant provider name in the ACRON installation path, in the `Log` directory. Note As diagnosis mode heavily influences the performance of the application, and the recorded messages can normally only be evaluated by Technical Support, you should only activate it when prompted to do so by Support. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.videc.de/acron-9.3/en/anlagenkonfiguration/prozessanbindung/provider/providerid/treiberauswahl/opc_unified-architecture-client.md?ask= ``` The question should be specific, self-contained, and written in natural language. 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