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 xor ord(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 then BaudRate1:= 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; |
发表于 2010-11-6 11:38:48
