sayantan

Hi there, Have you ever needed Modbus RTU using Netduino+ over a RS-485 network? Or do you need a Netduino with RS-485? Do it inexpensively with MAX483 connected directly to COM1 on the Netduino. Do you need a TCP to Serial Converter? You can do it with Netduino+ and the MAX483. Max483 works like a transceiver. The attached code allows to switch to transmit a Modbus message and turns on the receiver to catch the reply.

Hi caestrada,

i was trying out ur coding for my netduino plus 1 and rs485 communication, but while deploying the code its showindg

"Error 1 'System.IO.Ports.SerialPort' does not contain a definition for 'ReadByte' and no extension method 'ReadByte' accepting a first argument of type 'System.IO.Ports.SerialPort' could be found (are you missing a using directive or an assembly reference?) C:\Users\CSIO\Documents\Visual Studio 2010\Projects\ceNetduinoPlusModbusRTU42\ceNetduinoPlusModbusRTU42\Program.cs 277 40 ceNetduinoPlusModbusRTU42 "

this error, cn u pls help me to over come dis problem.

thank you.

 

using System; 

using System.Net;

using System.Text;

using System.IO.Ports;

using System.Net.Sockets;

using System.Threading;

using Microsoft.SPOT;

using Microsoft.SPOT.Hardware;

using SecretLabs.NETMF.Hardware;

using SecretLabs.NETMF.Hardware.NetduinoPlus;

 

namespace rs232

{

    public class Program

    {

        static SerialPort serial;

        static OutputPort Led = new OutputPort(Pins.ONBOARD_LED, false);

 

        public static void Main()

        {            

            // initialize the serial port for COM1 (using D0 & D1) 

 

            serial = new SerialPort("COM1",9600, Parity.None, 8, StopBits.One);

            // open the serial-port, so we can send & receive data        

            serial.Open();

            // add an event-handler for handling incoming data        

            serial.DataReceived += new SerialDataReceivedEventHandler(serial_DataReceived);

 

 

            // wait forever...        

            Thread.Sleep(Timeout.Infinite);

        }

 

        static void serial_DataReceived(object sender, SerialDataReceivedEventArgs e)

        {

            int bytesToRead = serial.BytesToRead;

           

            //start reading the stream 

            if (bytesToRead > 0)

            {

                // get the waiting data 

                byte[] buffer = new byte[bytesToRead];

 

                serial.Read(buffer, 0, buffer.Length);

               

                serial.Write(buffer, 0, buffer.Length);

 

                Led.Write(true);

            }

 

            Led.Write(false);

        }// write your code here

     

    }

}// this is the code m using 

in hyperterminal, if i press a charecter, it gets  displays  one time and the onboard led blinks, bt it doesnt send back the data.

 

this is the coding i'm using.

HI Chris, 

this is the shot of my set-up, but still i'm unable to communicate with pc. The netduino on-board led links when ever i press a botton from the keyboard.

Hey Lifanek,

I gone through the [color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]thread u suggested and i tried out  the coding, its displaying only "[/color]transmit thread works" after every 5 sec

[color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]I have a doubt that for receiving the output,  are u using any " hyperterminal software" or  any such software???[/color]

[color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]Thank You..[/color]

hello lifanek,

i'm really sorry first of all., i will definetly keep in mind what u said.

and yes i'm already using a [color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]MAX232 for PC communication (or USB to TTL)., [/color]

[color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]i have an ADM3485 IC for RS485, will it work.????[/color]