How Do I Communicate to a PLC using system.net.sockets and how do i read the data.

Question

0.00/5 (No votes)

See more:

As mentioned in the question, i need to find a way to use

VB

system.net.sockets

to communicate with the PLC and read the data, placing it into the listbox. I have tried many samples and they so far do not work for me, only Winsock does but i am not intending to us VB6 or below. The Winsock ActiveX or any other ActiveX Control out of the question

Pls help, newbie here. Very Urgent

P.S PLC is progammable logic controller and i need to communicate via MODBUS TCP/IP

Travis

Posted 31-Oct-11 16:08pm

Travis Singh

Updated 27-Aug-21 1:48am

v2

Add a Solution

Comments

Sergey Alexandrovich Kryukov 1-Nov-11 0:30am

Why do you think Winsock is related to ActiveX or VB6?
--SA

Sergey Chepurin 1-Nov-11 16:12pm

Shouldn't you ask this question on OPC Foundation http://opcfoundation.org/forum/?

4 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Sergey Alexandrovich Kryukov · Answer 1 · 2011-10-31T19:53:00

You are dealing with Modbus TCP/IP or Modbus over TCP (a.k.a. RTU/IP), which is not the same. This is the first thing you need to find in your documentation, If you know one you can learn another one based on Modbus RTU vs Modbus ASCII.

Start from here: http://en.wikipedia.org/wiki/Modbus[^].

This is a detailed description of Modbus TCP: and robust, it has since become one of the de facto standard communications protocols in the industry, and it is now amongst.

Your operation using C# is fairy simple: you connect to Modbus server using System.Net.Sockets.TcpClient and perform the communication using Modbus protocol. Essentially, you sequentially write/read to/from a network stream available from your instance of TcpClient after connection: send request — get response. See http://msdn.microsoft.com/en-us/library/system.net.sockets.tcpclient.aspx[^]. Do it in a separate thread.

This is a C# implementation of Modbus protocol you can use. All this requires pretty good experience with basic programming techniques and some with network programming and threading, which is fairly simple.

Good luck,

—SA

Espen Harlinn · Answer 2 · 2011-11-01T03:06:00

Solution 3

Take a look at this article:Modbus TCP class[^]

Best regards
Espen Harlinn

Posted 1-Nov-11 3:06am

Espen Harlinn

Comments

Sergey Alexandrovich Kryukov 1-Nov-11 14:23pm

Interesting reference, my 5, even though as an article it sucks, or should I say it's not an article at all?
--SA

Espen Harlinn 1-Nov-11 14:26pm

Yes, it's about tip sized - but the writer did provide a Modbus implementation

Travis Singh · Answer 3 · 2011-11-01T14:59:00

Dear SAKryukovv,

Thanks A lot!! The information has really helped. There is a problem,I can get a connection but i can't seem to write/read data from the PLC. Your help is greatly appreciated and could you show some example code for me to get started

Travis Singh

P.S i will try to place my code online so you can take a look at it

Dear Santosh,

Thanks, it was very informative and i understood about about connecting to PLC via RTU or serial port but i am looking for a TCP/IP communication. Your help was still very useful and i understood all of it

Thanks Again

Travis Singh

Menon Santosh · Answer 4 · 2011-10-31T17:14:00

hello friend

once i had already faced this type of problem plz check this code

use using System.IO.Ports;

C#

SerialPort port;
        string strport = String.Empty;
        int IBaudRate = 19200;
        int ITimeOut = 300;

//initialize port

C#

port = new SerialPort();
                port.PortName = portname;
                port.BaudRate = IBaudRate;
                port.DataBits = 8;
                port.StopBits = StopBits.One;
                port.Parity = Parity.None;
                port.ReadTimeout = ITimeOut;
                port.WriteTimeout = ITimeOut;
                port.Encoding = Encoding.GetEncoding("iso-8859-1");
                port.DataReceived += new SerialDataReceivedEventHandler(DataReceived);
                port.Open();
                port.DtrEnable = true;
                port.RtsEnable = true;

//Send data

C#

port.DiscardInBuffer();
port.DiscardOutBuffer();
readnow.Reset();
port.Write(command + "\r");
recieved = receive(timeout);

//receive data

C#

private void DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            if (e.EventType == SerialData.Chars)
                readnow.Set();

        }

How Do I Communicate to a PLC using system.net.sockets and how do i read the data.

4 solutions

Solution 2

Solution 3

Solution 4

Solution 1

Add your solution here

Preview 0