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We are currently using a free trail version of KEP Server for our OPC to communicate with our PLC. We were wondering if anyone knows of any good open source OPC software.

Rob_IGS
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  • Which PLCs are you using? If it is Siemens S5/S7 and you got their WinCC visualisation software installed, there's already an OPC server integrated without additional charge. – grimmig Apr 07 '11 at 06:23
  • There are several nowadays on github. – Prof. Falken Mar 06 '15 at 11:42
  • @Prof.Falken Can you point out a few? – user1496984 Apr 06 '15 at 20:25
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    @user1496984 I am looking at https://github.com/FreeOpcUa/freeopcua – Prof. Falken Apr 07 '15 at 08:47
  • If you don't strictly need OPC and your PLCs support Modbus RTU, you could try [unserver](https://unserver.xyz) - it provides a simple HTTP API to talk to devices. It's free for non-commercial use, but unfortunately it's not open source. – astreltsov Mar 22 '17 at 18:11

2 Answers2

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If you don't mind skipping the OPC server and communicating directly with the PLC you should have a look at libnodave.

grimmig
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Some vendors offer OPC servers for free with their PLCs, but I haven't seen any free OPC servers that supports multiple vendors like KepWare OPC server does. Neither free (unless you count time limited ones), neither open source ones. That saying, the best bet you can get is to get Delphi and make your own OPC servers and clients with free sources found here. I am not aware of free OPC server sources for other languages.

avra
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