delphi 电子秤 代码
时间: 2023-07-02 15:03:47 浏览: 46
以下是一个简单的 Delphi 代码示例,用于读取连接到计算机的串口电子秤数据:
```delphi
unit uMain;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class(TForm)
btnConnect: TButton;
btnDisconnect: TButton;
edtWeight: TEdit;
Label1: TLabel;
procedure btnConnectClick(Sender: TObject);
procedure btnDisconnectClick(Sender: TObject);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
private
{ Private declarations }
FComPort: THandle;
FDataBuffer: string;
procedure ReadComPort;
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
const
BUFFER_SIZE = 1024;
TIMEOUT = 500;
procedure TForm1.btnConnectClick(Sender: TObject);
var
DCB: TDCB;
Timeouts: TCommTimeouts;
begin
FComPort := CreateFile('\\.\COM1', GENERIC_READ or GENERIC_WRITE, 0, nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
if FComPort <> INVALID_HANDLE_VALUE then
begin
FillChar(DCB, SizeOf(DCB), 0);
DCB.DCBlength := SizeOf(DCB);
GetCommState(FComPort, DCB);
DCB.BaudRate := CBR_9600;
DCB.ByteSize := 8;
DCB.Parity := NOPARITY;
DCB.StopBits := ONESTOPBIT;
SetCommState(FComPort, DCB);
FillChar(Timeouts, SizeOf(Timeouts), 0);
Timeouts.ReadIntervalTimeout := MAXDWORD;
Timeouts.ReadTotalTimeoutConstant := TIMEOUT;
Timeouts.ReadTotalTimeoutMultiplier := MAXDWORD;
Timeouts.WriteTotalTimeoutConstant := TIMEOUT;
Timeouts.WriteTotalTimeoutMultiplier := MAXDWORD;
SetCommTimeouts(FComPort, Timeouts);
Application.OnIdle := ReadComPort;
end
else
ShowMessage('Failed to open COM1');
end;
procedure TForm1.btnDisconnectClick(Sender: TObject);
begin
Application.OnIdle := nil;
CloseHandle(FComPort);
end;
procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
if FComPort <> INVALID_HANDLE_VALUE then
CloseHandle(FComPort);
end;
procedure TForm1.ReadComPort;
var
Buffer: array[0..BUFFER_SIZE - 1] of Char;
BytesRead: DWORD;
i: Integer;
begin
while True do
begin
if ReadFile(FComPort, Buffer, BUFFER_SIZE, BytesRead, nil) then
begin
FDataBuffer := FDataBuffer + Copy(Buffer, 1, BytesRead);
i := Pos(#13#10, FDataBuffer);
if i > 0 then
begin
edtWeight.Text := Copy(FDataBuffer, 1, i - 1);
FDataBuffer := Copy(FDataBuffer, i + 2, Length(FDataBuffer) - i - 1);
end;
end
else
Break;
end;
end;
end.
```
在此示例中,我们使用 CreateFile 函数打开串口 COM1,并设置波特率为 9600、数据位为 8、无奇偶校验和 1 个停止位。然后,我们使用 SetCommTimeouts 函数设置读取和写入超时值,并在应用程序的 OnIdle 事件中调用 ReadComPort 函数来读取串口数据。
ReadComPort 函数循环读取串口缓冲区中的数据,直到读取失败或没有更多数据可读。每次读取时,我们将缓冲区的内容添加到 FDataBuffer 变量中。如果 FDataBuffer 包含了一个完整的重量值(以回车换行符结尾),则我们将该值更新到 edtWeight 组件中,并从 FDataBuffer 中删除该值。
请注意,此示例仅适用于特定型号的电子秤,并且需要根据您的电子秤型号进行修改。此外,请确保您已安装串口驱动程序,并且电子秤已正确连接到计算机的串口端口。