General topics regarding OPC Foundation and communication technology in general.

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Post by akshaysarode18 »

I have OPC UA Server running on PLC which is been setup using Codesys 3.5.

And I have LDS running on some IP address. How can I make the PLC to register itself to that LDS ?

Thank you

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Re: PLC OPC UA Server

Post by Support Team »


typically the way to register should be described in the product manual of the Codesys UA Server.

Generally the LDS (local discovery server) is meant to be "locally" (on the same box) where the UA Server is located. The idea behind is that on one box (PC) there could exsist several UA Servers, plus an LDS (running on port 4840) that has a list of all registered servers.

A PLC typically has only one (1) UA Server running, the PLC-UA-Server (Codesys), and because of that does not need any LDS. This one and only PLC Server should run on port 4840 directly. In some cases people use the LDS which is somewhere on a different PC in the network and they register "remotely". Event though this is not the intention it will be possible, however this typically is the job of a GDS (Global Discovery Server).

In order to register at the LDS, the Server "acts as a client" and must have a trusted relation to the LDS (server must trust the LDS, and LDS must trust the server). After excanging certificates and trust them, the UA Server can register at the LDS.

All UA-Servers build with our SDKs can do so out of the box (basic configuration within the configuration settings), however for the Codesys-Server we don't know if such basic functionality is already implemented, since it was not implemented with our SDK.

Please ask Codesys-Support for that.
Best regards
Unified Automation Support Team

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