Connecting to MODBUS PLC

MODBUS Plugin Configuration and test


MODBUS is an application layer messaging protocol, positioned at level 7 of the OSI model, that provides client/server communication between devices connected on different types of buses or networks.
It is currently implemented using:
TCP/IP over Ethernet at a reserved system port 502 on the TCP/IP stack
Asynchronous serial transmission
MODBUS is a request/reply protocol and offers services specified by function codes. MODBUS function codes are elements of MODBUS request/reply PDUs.

( Read more )

Collective blogs.

Guys. I had move your posts from your personal blogs to collective Ā«HelpĀ» blog, you can see a collective blogs names at bottom right of the page. Pls select the most appropriate blog when you post new topic. For do this you should be joined to appropriate blog. Look to the picture.

Also you can subscribe on new topics in joined blogs and new comments. Go to Ā«site settingsĀ» like showed in pict.

Your suggestions.

We are come back to active development, we need your suggestions for a fuser improovements for FreeSCADA. Post your suggestions in this blog.

For do this ā€” push button Ā«WriteĀ» situated in top left corner of page(while you logged in) ā€” you will see the form for creating new post, select blog Ā«DevelopmentĀ» and write your post.

Regards Alex.

New Site

We are launched new site. This is social blog engine. All news will be published in Ā«NewsĀ» blog. Releases will publish in Ā«ReleaseĀ» blog. Ā«TuttorialsĀ» for tuttorials :) You can register and ask your questions in Ā«HelpĀ» blog. Make your suggestions in Ā«DevelopmentĀ» blog. All discussions will be in comments threads for published topic.
For publishing topic you need to login and press button Ā«WriteĀ» in top-left coner. After this select blog in which you whant to post your topic and thats is.
Ohh users have a rating, any user after register take zerro rating and can write posts only in Development and Help blogs. Rating will increase in acording with user activity inside comunity, when user will exceed presetted treshold it will takes rights for posting in other blogs.
PS. Old site can be found there:

We are coming back.

After long pause we will started development againe. In short terms will be finished bugfixesd and will be made new release.

Tutorial 2

FreeSCADA has embedded language based on Python syntax which allows you
to customize your scheme in various ways. In this example I will show
how to handle events from visual elements and modify visual state of
these objects.

( Read more )

Tutorial 1

In this tutorial we will show how do you can define text blocks with Channels values.Ā 

( Read more )


Here is small update of FreeSCADA. There are two critical fixes:
  • Fix for the issue of retrieving big number of variables from CLServer reported by Seung Woo Lee.

  • Added command for Schema renaming and removing. ThisĀ functionality wasĀ overlooked
    inĀ previousreleases. Thanks toĀ Artur_K for pointing that.

You can get it from SF download page.

We are waiting for your comments on our new Forum.
Give it a try! :)


FreeSCADA is out. It includes the following improvements:
  • Remote access to data channels by HTTP protocol

  • Improved error handling and a number of other bugfixes

  • New Chart control to show channel trends in real-time

  • New ToggleButton control which acts like a checkbox, but has button look and feel

  • TextBox control with possibility to bind its value to data channels

  • ā€œcheck for updatesā€ command was added

You can get it from SF download page. Please note that
FreeSCADA now requires Service Pack 1 for.Net Framework 3.5.

Your comments are welcome!


New version of preview package has been created. It has a number of
bug-fixes and several major features. There you can find the following:
  • Scripting support + several examples. However better
    documentation is needed.
  • Ā«Import GraphicsĀ» command has
    been added.
  • New Variables view in Designer and Realtime. Perfect
    for runtime communication debugging.
  • Binding possibility from
    property grid was removed.
  • Added: ColorEditor, undo/redo
    functionality with supporting changes from property grid.
  • Adding
    more examples for scripting feature.
  • Support for dynamically
    loaded visual plugins.
  • Color binding is implemented as part of
    common binding editing dialog.
  • A lot of bugfixes for every
    FreeSCADA module.

Version (preview) is here
PS. Don't forget to uninstall earlier version before proceed with the
new install.