The standard installation of CODESYS includes an OPC UA Server. You can use it to access the variable interface of the controller via a client. The OPC UA Server communicates with connected OPC UA Clients over a separate TCP connection. That is why these connections have to be examined again separately with regard to security.
The OPC UA Server can now be safeguarded by using encrypted communication to the client and OPC UA user management. You will find the possible settings for this in the following sections:
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In runtime version 3.5 SP17 and higher, a device user management has to be set up by default for access to the CODESYS runtime systems. However, for the OPC UA Server it is possible to continue to allow anonymous access if this is explicitly permitted. This permission is granted in the “Change Communication Policy” dialog on the ⮫ Communication Settings tab of the device editor.
The CODESYS OPC UA server supports the following features:
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Browsing of data types and variables
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Standard read/write services
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Notification for value changes: subscription and monitored item services
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Encrypted communication according to "OPC UA standard (profile: Basic256SHA256)"
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Imaging of the IEC application according to "OPC UA Information Model for IEC 61131-3"
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Supported profile: "Micro Embedded Device Server Profile"
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Number of sessions
By default, monitored items and subscriptions are not restricted. The number depends on the performance of the respective platform.
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Sending of events according to the OPC UA standard
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Communication with a data source OPC UA Client
For more information, see: ⮫ “Establishing the Connection of a Data Source OPC UA Client to an OPC UA Server ”
The OPC UA Client UAExpert is cited many times in this chapter. UAExpert is a product of the vendor "Unified Automation".
For more information, see: ⮫ Unified Automation
When you create a ⮫ “IEC Symbol Set Configuration ” with the Communication Manager, OPC UA access is automatic. With the previous symbol configuration, you need to create a project for OPC UA access according to the following instructions.
Application note
How to install and configure an OPC V2 or OPC V3 server and how to use it for AC500 PLCs is described in the application note ⮫ How to use OPC server.
Application example
To gain a deeper understanding of the OPC protocol and to configure the PLC accordingly, an ⮫ application example is available.