private void btnStop_Click(object sender, EventArgs e)
{
cntrl.StopProcess();
richTextBox1.Text = " RTU Emulator Has been Stopped";
richTextBox1.Font = new Font(richTextBox1.Font, FontStyle.Bold);
richTextBox1.BackColor = Color.Red;
richTextBox1.ForeColor = Color.White;
btnasync.Enabled = true;
btnStop.Enabled = false;
sb.Clear();
}