How to send commands to SCPI Terminal for a power supply

[Lalaluye]

Hi I'm trying to write a program to send commands to SCPI Terminal for a HMP2030 power supply with a USB Interface. So far my approach has been writing a code using serial ports. I have written a code that is able to open the comport, but when I write to it, and then read from it, I get an empty string. I'm wondering if using serial port is the correct approach to this?

Private comm As New CommManager()
    Private Sub MainForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim read As String

        System.IO.Ports.SerialPort.GetPortNames()

        comm.StopBits = 1
        comm.DataBits = 8
        comm.BaudRate = 9600
        comm.Parity = "None"
        comm.PortName = "COM18"
        comm.OpenPort()
        comm.Message = "*IDN?"
        comm.Type = CommManager.MessageType.Normal
        comm.WriteData("*IDN?")
        read = comm.ReceiveSerialData()

    End Sub

#Region "WriteData"
    Public Sub WriteData(ByVal msg As String)
        Select Case CurrentTransmissionType
            Case TransmissionType.Text
                'first make sure the port is open
                'if its not open then open it
                If Not (comPort.IsOpen = True) Then
                    comPort.Open()
                End If
                'send the message to the port
                comPort.Write(msg)
                'display the message
                _type = MessageType.Outgoing
                _msg = msg + "" + Environment.NewLine + ""
                'MsgBox(_type, _msg)
                Exit Select
            Case TransmissionType.Hex
                Try
                    'convert the message to byte array
                    Dim newMsg As Byte() = HexToByte(msg)
                    If Not write Then
                        MsgBox(_type, _msg)
                        Exit Sub
                    End If
                    'send the message to the port
                    comPort.Write(newMsg, 0, newMsg.Length)
                    'convert back to hex and display
                    _type = MessageType.Outgoing
                    _msg = ByteToHex(newMsg) + "" + Environment.NewLine + ""
                    MsgBox(_type, _msg)
                Catch ex As FormatException
                    'display error message
                    _type = MessageType.Error
                    _msg = ex.Message + "" + Environment.NewLine + ""
                    MsgBox(_type, _msg)
                Finally
                    ' _displayWindow.SelectAll()
                End Try
                Exit Select
            Case Else
                'first make sure the port is open
                'if its not open then open it
                If Not (comPort.IsOpen = True) Then
                    comPort.Open()
                End If
                'send the message to the port
                comPort.Write(msg)
                'display the message
                _type = MessageType.Outgoing
                _msg = msg + "" + Environment.NewLine + ""
                MsgBox(MessageType.Outgoing, msg + "" + Environment.NewLine + "")
                Exit Select
        End Select
    End Sub
#End Region

#Region "Read Data"
    Function ReceiveSerialData() As String
        ' Receive strings from a serial port.
        Dim returnStr As String = ""

        Try
            comPort.ReadTimeout = 10000
            Do
                Dim Incoming As String = comPort.ReadLine()
                If Incoming Is Nothing Then
                    Exit Do
                Else
                    returnStr &= Incoming & vbCrLf
                End If
            Loop
        Catch ex As TimeoutException
            returnStr = "Error: Serial Port read timed out."
        Finally
            If comPort IsNot Nothing Then comPort.Close()
        End Try

        Return returnStr
    End Function
#End Region

*REPHRASE: How to send SCPI commands to serial ports?