unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, SPComm, StdCtrls, TeEngine, Series, ExtCtrls, TeeProcs, Chart;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Comm1: TComm;
    Button2: TButton;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Chart1: TChart;
    Series1: TLineSeries;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Comm1ReceiveData(Sender: TObject; Buffer: Pointer;
      BufferLength: Word);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  i:integer;
  rbuf : array[1..8] of byte;
implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
    i:=0;
    comm1.commname := 'com1';
    comm1.baudrate := 9600 ;
    comm1.startcomm;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
    comm1.stopcomm ;
    label2.Caption:='';
    i:=0;
    chart1.Series[0].Clear;
end;

procedure TForm1.Comm1ReceiveData(Sender: TObject; Buffer: Pointer;
  BufferLength: Word);
  var
  data : double ;
begin

    move(buffer^,pchar(@rbuf)^,bufferlength);
    data := (rbuf[1] * 256) + rbuf[2] ;
    data := data *0.0625 ;
    label2.caption := floattostr(data);
    if (chart1.Series[0].MaxXValue <= i) then
      chart1.BottomAxis.Maximum:=i+10;
  chart1.Series[0].addxy(i,data,'',clteecolor);
  i:=i+1;
end;

end.