We are try to write the ActiveX which would read and write data in WinCC tags in the graphic editor. How data writing in WinCC tags from ActiveX is realized?

 

You can use OPC to read / write WinCC tags. There is a simple Excel based example in the WinCC manual. If you need a more specific example then I would recommend asking on the Siemens support forum https://www.automation.siemens.com/WW/forum/en/guests/Conference.aspx?ForumID=162

Regards,
Salma

 

I don't know the amount of tags you want to read and write, but you might consider defining properties and events in your activeX.

In the Graphics Designer, you can then connect the tags to the properties of your ocx-control.

These properties can be written and read by your VB6-ocx-application.
When you define events, you can use them to write or read certain values, by coding some C - or VBS scripting in the Graphics Desinger.

This way you don't need OPC, and it works a bit faster if you don't have to many tags.
If you want to use OPC, you can download a free OPC client with sample source code on http://www.kepware.com

 

Developing an ActiveX for WinCC may be real headache.

Here is a link for it:
http://indanotes.blogspot.com/2009/08/developing-activex-for-wincc-flexible.html