
Imports System.IO
Imports System.Environment

Module Module1


  Sub Main()

    Dim argv() As String = System.Environment.GetCommandLineArgs()
    Dim serialPort As YSerialPort
    Dim errmsg = ""
    Dim cmd As String
    Dim slave, reg, val As Integer

    REM Setup the API to use local USB devices. You can
    REM use an IP address instead of 'usb' if the device
    REM is connected to a network.

    If (YAPI.RegisterHub("usb", errmsg) <> YAPI.SUCCESS) Then
      Console.WriteLine("yInitAPI failed: " + errmsg)
      End
    End If

    If (argv.Length > 1) Then
      serialPort = YSerialPort.FindSerialPort(argv(1))
    Else
      serialPort = YSerialPort.FirstSerialPort()
      If serialPort Is Nothing Then
        Console.WriteLine("No module connected (check USB cable)")
        End
      End If
    End If

    Console.WriteLine("Please enter the MODBUS slave address (1...255)")
    Console.WriteLine("Slave: ")
    slave = Convert.ToInt32(Console.ReadLine())

    Console.WriteLine("Please select a Coil No (>=1), Input Bit No (>=10001),")
    Console.WriteLine("Input Register No (>=30001) or Holding Register No (>=40001)")
    Console.WriteLine("No: ")
    reg = Convert.ToInt32(Console.ReadLine())
    While (True)
      If reg >= 40001 Then
        val = serialPort.modbusReadRegisters(slave, reg - 40001, 1)(0)
      ElseIf (reg >= 30001) Then
        val = serialPort.modbusReadInputRegisters(slave, reg - 30001, 1)(0)
      ElseIf (reg >= 10001) Then
        val = serialPort.modbusReadInputBits(slave, reg - 10001, 1)(0)
      Else
        val = serialPort.modbusReadBits(slave, reg - 1, 1)(0)
      End If
      Console.WriteLine("Current value: " + Convert.ToString(val))
      Console.WriteLine("Press ENTER to read again, Q to quit")
      If ((reg Mod 40000) < 10000) Then Console.WriteLine(" or enter a new value")

      cmd = Console.ReadLine()
      If cmd = "q" Or cmd = "Q" Then End

      If (cmd <> "" And (reg Mod 40000) < 10000) Then
        val = Convert.ToInt32(cmd)
        If reg >= 40001 Then
          serialPort.modbusWriteRegister(slave, reg - 40001, val)
        Else
          serialPort.modbusWriteBit(slave, reg - 1, val)
        End If
      End If
    End While





  End Sub


End Module
