Modbus RTU Master Help Needed ...

Sun, 11 Jul 2010 07:40:50 -0700

Posted a 'new message on the Visual Basic forum.

Hi there ....

I am new in VB(2008 Express) and I want to develop Modbus RTU Master program ..

I am expert in Modbus communication and I have designed the Modbus pre-programmed remote controls ,, Now I want to interface some Modbus RTU slave devices to my own developed application ... and looking for kind guidance ..

I am much familiar with the Modbus RTU syntax and I've tried following to initiate the the master query but I am getting initial 3 bytes ok ,, rest of them are changing the values on COM port so slave is not responding to my command ..

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Private Sub Button10_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button10.Click

Dim BYTE1 As Byte = 1
Dim BYTE2 As Byte = 6
Dim BYTE3 As Byte = 95
Dim BYTE4 As Byte = 201
Dim BYTE5 As Byte = 254
Dim BYTE6 As Byte = 1
Dim BYTE7 As Byte = 202
Dim BYTE8 As Byte = 64

SerialPort1.Write(Chr(BYTE1) & Chr(BYTE2) & Chr(BYTE3) & Chr(BYTE4) & Chr(BYTE5) & Chr(BYTE6) & Chr(BYTE7) & Chr(BYTE8))

End Sub
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Thanks in advance for the guidance and help

Maan

maan2k's Feed - Programmer's Heaven

Modbus RTU Master Help Needed ...