CRC-16校验(多项式为x16+x15+x2+1):

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最新推荐文章于 2025-03-17 11:29:12 发布

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CRC-16校验(多项式为x16+x15+x2+1):

type
{CRC校验}
TDataByte = array of byte;

const
  CRCHi: array [0..255] of byte =
  (
$00, $C1, $81, $40, $01, $C0, $80, $41, $01, $C0, $80, $41, $00,
$C1, $81, $40, $01, $C0, $80, $41, $00, $C1, $81, $40, $00, $C1,
$81, $40, $01, $C0, $80, $41, $01, $C0, $80, $41, $00, $C1, $81,
$40, $00, $C1, $81, $40, $01, $C0, $80, $41, $00, $C1, $81, $40,
$01, $C0, $80, $41, $01, $C0, $80, $41, $00, $C1, $81, $40, $01,
$C0, $80, $41, $00, $C1, $81, $40, $00, $C1, $81, $40, $01, $C0,
$80, $41, $00, $C1, $81, $40, $01, $C0, $80, $41, $01, $C0, $80,
$41, $00, $C1, $81, $40, $00, $C1, $81, $40, $01, $C0, $80, $41,
$01, $C0, $80, $41, $00, $C1, $81, $40, $01, $C0, $80, $41, $00,
$C1, $81, $40, $00, $C1, $81, $40, $01, $C0, $80, $41, $01, $C0,
$80, $41, $00, $C1, $81, $40, $00, $C1, $81, $40, $01, $C0, $80,
$41, $00, $C1, $81, $40, $01, $C0, $80, $41, $01, $C0, $80, $41,
$00, $C1, $81, $40, $00, $C1, $81, $40, $01, $C0, $80, $41, $01,
$C0, $80, $41, $00, $C1, $81, $40, $01, $C0, $80, $41, $00, $C1,
$81, $40, $00, $C1, $81, $40, $01, $C0, $80, $41, $00, $C1, $81,
$40, $01, $C0, $80, $41, $01, $C0, $80, $41, $00, $C1, $81, $40,
$01, $C0, $80, $41, $00, $C1, $81, $40, $00, $C1, $81, $40, $01,
$C0, $80, $41, $01, $C0, $80, $41, $00, $C1, $81, $40, $00, $C1,
$81, $40, $01, $C0, $80, $41, $00, $C1, $81, $40, $01, $C0, $80,
$41, $01, $C0, $80, $41, $00, $C1, $81, $40
) ;

CRCLo: array [0..255] of  byte =
(
$00, $C0, $C1, $01, $C3, $03, $02, $C2, $C6, $06, $07, $C7, $05,
$C5, $C4, $04, $CC, $0C, $0D, $CD,$0F, $CF, $CE, $0E, $0A, $CA,
$CB, $0B, $C9, $09, $08, $C8, $D8, $18, $19, $D9, $1B, $DB, $DA,
$1A, $1E, $DE, $DF, $1F, $DD, $1D, $1C, $DC, $14, $D4, $D5, $15,
$D7, $17, $16, $D6, $D2, $12, $13, $D3, $11, $D1, $D0, $10, $F0,
$30, $31, $F1, $33, $F3, $F2, $32, $36, $F6, $F7, $37, $F5, $35,
$34, $F4, $3C, $FC, $FD,$3D, $FF, $3F, $3E, $FE,$FA, $3A, $3B,
$FB, $39, $F9, $F8, $38, $28, $E8, $E9, $29, $EB, $2B, $2A, $EA,
$EE, $2E, $2F, $EF, $2D,$ED, $EC, $2C, $E4, $24,$25, $E5, $27,
$E7, $E6, $26, $22, $E2, $E3, $23, $E1, $21, $20, $E0, $A0, $60,
$61, $A1, $63, $A3, $A2, $62, $66, $A6, $A7, $67, $A5, $65, $64,
$A4, $6C, $AC, $AD,$6D, $AF, $6F, $6E, $AE,$AA, $6A, $6B, $AB,
$69, $A9, $A8, $68, $78, $B8, $B9, $79, $BB, $7B, $7A, $BA, $BE,
$7E, $7F, $BF, $7D,$BD, $BC, $7C, $B4, $74,$75, $B5, $77, $B7,
$B6, $76, $72, $B2, $B3, $73, $B1, $71, $70, $B0, $50, $90, $91,
$51, $93, $53, $52, $92, $96, $56, $57, $97, $55, $95, $94, $54,
$9C, $5C, $5D, $9D, $5F, $9F,$9E, $5E, $5A, $9A, $9B, $5B, $99,
$59, $58, $98, $88, $48, $49, $89, $4B, $8B, $8A, $4A,$4E, $8E,
$8F, $4F, $8D, $4D, $4C, $8C,$44, $84, $85, $45, $87, $47, $46,
$86, $82, $42, $43, $83, $41, $81, $80, $40
);

function crc16(var dataaddress :byte; datalength: byte): word;
var
   hi: byte;
   lo: byte;
   i: byte;
   index: byte;
   datadd: pbytearray;
begin
   hi := $FF;
   lo := $FF;
datadd := @dataaddress;
   i := 0;
   while (datalength > 0) do
   begin
      index := (hi xor datadd^ );
      i := i + 1;
      hi := lo xor crchi[index];
   lo := crclo[index];
   datalength := datalength - 1;
   end;
   crc16 := hi shl 8 or lo;
end;

function ModBusCRC(Data: string): string; //生成modbus CRC数据
var
   CRC16Lo, CRC16Hi, CL, CH, UseHi, UseLo:Dword;
   i, index: integer;
begin
   CRC16Lo := $FF; //CRC16Lo为CRC寄存器低8位
   CRC16Hi := $FF; //CRC16Hi为CRC寄存器高8位
   CL := $01;
   CH := $A0; //  A001 H 是CRC－16多项式代码
   for i := 1 to Length(Data) do
   begin
      CRC16Lo := CRC16Lo xorord(Data); //每一个数据与CRC寄存器异或
      for index := 0 to 7 do
      begin
      UseHi := CRC16Hi;
      UseLo := CRC16Lo;
      CRC16Hi := CRC16Hi shr 1;
      CRC16Lo := CRC16Lo shr 1;//右移一位
      if ((UseHi and $1) = $1)then //如果高位字节最后一位是1的话
         CRC16Lo :=CRC16Lo or $80; //低位字节右移后前面补1

      if ((UseLo and $1) = $1)then //如果LSB 为1，则与多项式进行异或
      begin
         CRC16Hi :=CRC16Hi xor CH;
         CRC16Lo :=CRC16Lo xor CL;
      end;
      end;
   end;

   Result := IntToHex(CRC16Lo, 2) + IntToHex(CRC16Hi,2);
end;

进制转换:
function StrToHexStr(const S:string):string;
//字符串转换成16进制字符串
var
  I:Integer;
begin
  for I:=1 to Length(S) do
  begin
if I=1 then
   Result:=IntToHex(Ord(S[1]),2)
else Result:=Result+' '+IntToHex(Ord(S[I]),2);
  end;
end;

function HexStrToStr(const S:string):string;
//16进制字符串转换成字符串
var
  t:Integer;
  ts:string;
  M,Code:Integer;
begin
  t:=1;
  Result:='';
  while t<=Length(S) do
  begin
while not (S[t] in ['0'..'9','A'..'F','a'..'f']) do
   inc(t);
if (t+1>Length(S))or(not (S[t+1] in['0'..'9','A'..'F','a'..'f'])) then
   ts:='$'+S[t]
else
   ts:='$'+S[t]+S[t+1];
Val(ts,M,Code);
if Code=0 then
   Result:=Result+Chr(M);
inc(t,2);
  end;
end;

function Hex2Dec(Hexs: string): string;
//十六进制转换成十进制
var
  i,j: integer;
  res,base: LongWord;
begin
  res := 0;
  for i:=1 to Length(Hexs) do
  begin
base := 1;
for j:=1 to Length(Hexs)-i do
   base := base * 16;
case Hexs of
   '0'..'9': res := res + (Ord(Hexs) - Ord('0')) * base;
   'a'..'f': res := res + (Ord(Hexs) - Ord('a') + 10) *base;
   'A'..'F': res := res + (Ord(Hexs) - Ord('A') + 10) *base;
end;
  end;
  result := inttostr(res);
end;

function BcdToHex(Hexstr: string): string;
//BCD转换成十六进制
var
  i: integer;
  returnstr : string;
begin
  result := '0';
  try
returnstr := IntToHex(StrToInt64(Hexstr),4);
for i := 1 to length(returnstr) do
begin
   if returnstr[1] = '0' then
   delete(returnstr,1,1);
end;
Result := returnstr;
  except
  end;
end;

function DecToHex(DecS : string):string;
//十进制转换成十六进制
var i : integer;
begin
i := StrToInt(DecS);
Restult := IntToHex(i,2);
end;

使用Comport控件进行modbus通信的简单例子:

procedure TMainForm.btnReadBuadRateClick(Sender: TObject); //波特率
var
  str,str1,BaudRate1 :string;
  i : integer;
  obj : PAsync;
begin
   i :=0;
   if (edAdd.text ='')and (not CheckBox1.checked) then
      showmessage('请输入装置地址')
   else
   begin
   if  checkBox1.checked then //广播方式
      Address := '00'
   else
      Address := DecToHex(edAdd.text);
      if not(address ='error' )then  //判断地址是否超出0~255地址范围
      begin
      str :=Address+'03'+'00'+'02'+'00'+'01';  //差校验数值
      str := str+ModBusCRC(HexStrToStr(str));//发送的字符串(包含地址,功能码,数据,CRC)

      InitAsync(obj);
         try
         ComPort.WriteStrAsync(hexstrToStr(str),obj);
         SendMemo.Text :=SendMemo.text+ str+' ';
         i := i+1;
         if (i>30000) then
         begin
         ComPort.AbortAllAsync ;
         showmessage('通信失败,请重新发送!');
         end;
         ComPort.WaitForAsync(obj);
         sleep(500);//发送命令后等待500MS，保证数据的完整性；
         ComPort.ReadStr(Str, 20);//读取接收缓存区20个字节数；
        comport.ClearBuffer(true,true);//清除发送区和接收区，准备下一个通道通信；
         finally
         DoneAsync(obj);
         end;

         RXMemo.text :=RXMemo.text +StrToHexstr(str);

      if (str = '') then
         showmessage('没有收到数据，请重发!')
         else
   begin
//       if(not CRCCheck(str)) then
//       showmessage('接收数据错误!')
//       else
//          begin
         for I:=1 to Length(str)do//将接收到的数据作处理
            begin
            str1:=IntToHex(Ord(Str),2) ;
            if i= 5 thenBaudRate1:= str1;//测量值的低位字节
            end;
         end;
         edit1.text := Hex2Dec(BaudRate1);
         edBaudRate.text :=BaudRateInterv(Hex2Dec(BaudRate1));
      end;
//       end;
      str := '';
      end;

end;