Serial Port not writing back

[Dubya007]

I'm trying to connect to a Mettler Toledo Scale via a serial port to read in the weight of an object and output the wieght into a label or text box on the form.

so I have a button and a text box. Here is my code

Private Sub btnSendText_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSendText.Click
        Dim Port As SerialPort = New SerialPort("COM1", 9600, Parity.None, 8, StopBits.One)
        Port.Open()
        txtWeight.Text = Port.ReadLine()
        Port.Close()

    End Sub

My problem is that the program hangs there doing nothing when I click the button.

Does anyone know why?