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One PLC two UniOPC servers


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Is it possible to read one PLC (V130 in my case) with more than one UniOPC server software which are running in different computers?  

I have an application where V130 is read from one PC by UniOPC server and I need read same PLC with other UniOPC server located in other PC. All tags are identical.

I installed UniOPC program to both PC and they both can read the PLC but not simultaneously. I can connect both UniOPC with PLC, but only firstly connected OPC can read tag values. Secondly connected OPC tags quality is //Uncertain, non-specific//  and tag values are zeros. Both UniOPC sever have identical configuration.

Is it in principle not possible to read one PLC with two UniOPC or I have problems with settings?




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I never tried it but I don't see a reason why it wouldn't be possible.

Are you using serial or Ethernet? Set different ports if you are using Ethernet.


I tried it and it works, two PCs can communicate with the same PLC through UniOPC. I used Ethernet connection with different ports.

Edited by Isakovic
I tried the problem in question on the equipment
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Hello Meelis


Theoretically it would be possible to communicate with two PC,s and so two different UNIOPC servers to the V130

But not with the same settings.


The V130 supports four ethernet sockets and for the required setup you would need two ethernet sockets.

If you also want to connect over ethernet with visilogic , then his would occupy a third socket.

Default settings in UNIOPC is the PLC name and port number 20256.(Is also default in remote operator and Visilogic)

In both UNI OPC servers you have probably the same port number setting and that’s the reason why both your PC,s won’t communicate simultaneously to the V130.

In the help file from visilogic you will find the default port numbers and settings of socket 0 to 3.

Search for “socket init”.

You also can find info in this help file  what program code is needed in the V130 to override the default settings.

Let’s say you don’t need the default configuration from socket 0 that is configured for UDP with default port number 20000 then to change this you need a socket init where the configuration is

Socket 0 , Protocol=TCP, port number is 20258 , Client/Server=Server. In one of the Uniopc,s you also have the change the default 20256 port to 20258.

If you don’t need Modbus tcp over ethernet you could also try to change the port number in one of the Uniopc servers from 20256 to 502 and then no extra program code in the V130 is needed because port 502 is default on socket 2 , TCP and server.


Never tested it and I don’t know if things work with port 20258 or just another free higher number but les then 65535 but this approach is the only way I know to get it working.


Kind regards





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