unit1.pas

RS232串口通讯随书源码

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, ExtCtrls, TComm1;

type
  TForm1 = class(TForm)
    mCmd: TMemo;
    mReceive: TMemo;
    Label1: TLabel;
    Label2: TLabel;
    Comm1: TComm;
    Timer1: TTimer;
    txtNowValue: TEdit;
    Label3: TLabel;
    Button1: TButton;
    Button2: TButton;
    rdCOM: TRadioGroup;
    Button4: TButton;
    procedure Button4Click(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  CmdFlag : Boolean;
  Procedure TimeDelay(DT:DWORD);

implementation

{$R *.DFM}

procedure TForm1.Button4Click(Sender: TObject);
begin
   //确定使用的通信端口号码
  if rdCOM.ItemIndex =0 then
    Comm1.CommPort := pnCOM1
  else
    Comm1.CommPort := pnCOM2;
  //打开通信端口
  Comm1.PortOpen := True;
  Timer1.Enabled := True; //激活定时器
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  //激活命令标志
  CmdFlag := True;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
var
  Buf : String;
  Pos1,Pos2:Integer;
begin
//若命令标志激活，则执行以下的程序
if CmdFlag then
  begin
   //将命令区中的命令送出
   Comm1.OutputString(mCmd.Text + Chr(10) );
   TimeDelay(300); //延迟一下
   //接收结果
   mReceive.Text := Comm1.Input;
   CmdFlag := False; //标志取消
  end;
 //不断送出读值的命令
 Comm1.OutputString(':M_D:C_D?'+ Chr(10)+Chr(13));
 TimeDelay(300);
 Buf := Comm1.Input ;
 //判断DATA字符串的位罝
 Pos1 := Pos('DATA',Buf);
 //判断逗号的位置
 Pos2 := Pos(',',Buf);
 //二个位置的中间就是数值的范围
 if (Pos1>0) and (Pos2>0) then
   txtNowValue.Text := Copy(Buf,Pos1+4,Pos2-(Pos1+4));
end;


//以下是延迟函数，单位毫秒
Procedure TimeDelay(DT:DWORD);
var
 TT:DWORD;
begin
  //取得现在的Tick值
  TT:=GetTickCount();
  //计算Tick差值是否超过设置值
  while GetTickCount()-TT<DT do
   Application.ProcessMessages; //释放控制权
end;


procedure TForm1.Button2Click(Sender: TObject);
begin
 //结束程序
 Close;
end;

end.