thanks to all

Also for someone confused like i was, here is my explanation:

Function Trend Control can plot x[],y[] arrays of points from an existing  csv file stored on the machine

example

https://support.industry.siemens.com/cs/ru/ru/view/109481693/en

uses a VB script, that takes those arrays, clears existing .csv, writes in a FOR loop to the .csv file (archive), does error messaging along the way

then a screen with the Function Trend Control is updated

to summarise

1) generate x,y arrays in PLC

2) establish connection to x,y arrays in HMI, historic data - .csv archive

3) copy the VB script

4) add an UPDATE plot button, that calls the VB script and updates the screen with trend

5) add trend and use the archive (historic data)

Yolov

Dear BWS,

You simply don't listen!!! As Navnag told you, the Function Trend Control is just what you need!!!!!
Obviously you did not configure something correctly and that is why you get a trend of just one value!
The Function Trend Control is complicated and need more thorough study.
In my project I use X-Y plot and I use of course Function Trend Control.

Something more! With Function Trend Control you can have ideal curve which can be stored into User Archive. You can develop a C-script which can read cyclically your model from CSV file and store it into User Archive table. The Function Trend Control will update its view from the User Archive table.

As far as I know in WinCC v6.2, Function Trend Control can get ideal curve directly from CSV format file (I am still don't work with WinCC v6.2).

regards,
Svetozar Yolov