This is a VB.net project for Reading and Writing Modbus TCP's registers. The beginning is where I am looking for Sample program VB.net of Modbus TCP's communication. And then I found a sample project in CodeProject.com, here: http://www.codeproject.com/Tips/16260/Modbus-TCP-class This is a VB.net project for Modbus TCP's communication built with C# language, by Stephan Stricker. The original project contain of 2 projects. I open all of that and convert with site above. Then I make a new project with VB language. I choose .Net 2.0 framework. This new project named Modbus Sample VB. In my new project, I just create one project, which is consist of one form and one module. I move Modbus TCP class to module ModbusTCP, and I copy all objek in frmStart and paste it on frmStart in my new project. It amazing, the translated script is almost perfect, only a few lines error. Picture below shows the error lines in Module