title: read and write data from AB PLC or any other controllers using C#
body: <p>I am new to C# and .NET programming so please forgive me if my problem doesn't make sense to you. I am trying to make an application that can read and write data from PLC(Allen Bradley compact logix) to my application. Here are my visions :1) PLC acts as server and the host computer as a client.
  2) PLC listens or waits for Host computer.
  3) PLC accepts client or Host computer.
  4) Host computer sends data or command to PLC to do some task. Example, create a simple button that turns on and off memory bit on the PLC. 
  I am comfortable on working from 1,2 and 3 but I don't know how am I going to do part 4. In the past, I have built simple app to have two computers to exchange strings or text to each other using TCP/IP but instead of sending string I want to send command so that I can change memory bit of PLC.</p>
  
  <p>I only need help in part 4. </p>
  
  <p>I am using C# programming language to accomplish this.</p>