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NDde connect to PLC or InTouch in C# ?

Apr 15, 2009 at 9:26 AM
Hi, is this possible? I need read and write data from and to PLC in my windows C# application. Please help me.
Apr 21, 2009 at 9:38 PM
I am trying to do the same thing also.  This site seems to be pretty idle.  People are asking questions but no one is answering.  I am kind of a nubie but I do have it working at a certain level but I have a few questions.  InTouch connects and starts an Advise loop.  It seems to work at that level.  I can toggle a bit from InTouch (no PLC for now) but I don't know how to use this dll enough to figure out how to change the data and allow InTouch to receive the updated data.  

I am a Controls Engineer, so I understand the PLC side really well but the .net side is not my forte.  If you, or anyone else out there is a programming guru and can help that would be nice.  I am using VB .net 2008 Express.

Jun 2, 2009 at 5:45 PM

Hi, YES IT IS possible to do so.

You have to follow these steps:

1) Create the client object sending the Application and Topic Name, in case of PLC (Rockwell) "RSLinx" and then the name of the program (in PLC)

2) Client.connect

3) client.request(Name1[pointer].TAG)

Name1: Name of UDDT structure

pointer: pointer inside UDDT

TAG: tag name

3) client.poke()

Will allow you to write in the PLC

4) client.disconnect


Let me know if I can provide more help.

Jun 24, 2009 at 7:01 AM


Thanks VDanielV. I want try this with RSLinx and C#. I have done this in but with other module. Module is from RSLinx software, and module name is RsiOpcAuto.dll. I want re-make this in C# with NDde.dll. I hope will be done :)

Ivan Suster, Slovakia