//test OPC connection
        private void button3_Click(object sender, EventArgs e)
        {
            this.button3.Enabled = false;
            this.button3.Text    = "Testing...";
            OPC_class opc_obj = new OPC_class(textBox3.Text, textBox4.Text, textBox2.Text);

            Settings1.OPCVariablesInitialized = opc_obj.VariablesInitialized;
            label6.Text          = (Settings1.OPCVariablesInitialized) ? "Ok" : "Not OK";
            this.button3.Enabled = true;
            this.button3.Text    = "Test connection";
        }
 //test OPC connection
 private void button3_Click(object sender, EventArgs e)
 {
     this.button3.Enabled = false;
     this.button3.Text = "Testing...";
     OPC_class opc_obj = new OPC_class(textBox3.Text,textBox4.Text,textBox2.Text);
     Settings1.OPCVariablesInitialized = opc_obj.VariablesInitialized;
     label6.Text = (Settings1.OPCVariablesInitialized) ? "Ok" : "Not OK";
     this.button3.Enabled = true;
     this.button3.Text = "Test connection";
 }