crc16 и modbus

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revo (2003-12-02 17:14) [0]

Кто нибудь работал с modbus? Как там вычислять CRC?

С уважением,
Revo.

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Вася Пупкин (2003-12-02 21:21) [1]

Кто-нибудь работал с yandex? поиск по modbus crc16.
Насколько я помню, в описании протокола это есть. И даже с примером на С.
ps могу ошибаться - работал давно с Modbus+, все материалы, которые остались - дома и глубоко зарыты. Может, поищу вечером.

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Adder (2003-12-02 23:27) [2]

Вот... держи Unit на BP7
unit crc; interface uses kuodata; function crc16(Start:byte;UsDataLen:byte;PMes:PVMessage):word; implementation const (* Table of CRC values for high-order byte *) auchCRCHi: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 ); (* Table of CRC values for low-order byte *) auchCRCLo: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(Start:byte;UsDataLen:byte;PMes:PVMessage):word; var i:word; uIndex:byte ; (* will index into CRC lookup*) uchCRCHi : byte; uchCRCLo :byte; begin { $4409} {PMes:=@Mes;} uchCRCHi := $FF ; (* high CRC byte initialized *) uchCRCLo := $FF ; (* low CRC byte initialized *) for i:=Start to UsDataLen-1 do begin uIndex := uchCRCHi xor PMes^[i] ; (* calculate the CRC*) uchCRCHi := uchCRCLo xor auchCRCHi[uIndex] ; uchCRCLo := auchCRCLo[uIndex] ; end; crc16:= (uchCRCHi shl 8 or uchCRCLo) ; end; end.

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Adder (2003-12-02 23:39) [3]

в kuodata.pas:
Type
Vmessage = array [0..255] of byte;
PVMessage = ^Vmessage;

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GEN++ (2003-12-03 00:15) [4]

Сейчас с ним работаю. Даже небольшой "сервер " сделал.
А CRC16 для 3-х байтовой последовательности вычисляю так:
function TForm1.CHSM(SID,nomBlk,kolBlk:byte):word;
//подсчет контрольной суммы байтовой последовательности
//<SID>,<outReq>,<kolBlk>
var
b:array[1..3] of byte;//массив байт для которых считается CRC16
//описан в модуле
//как глобальная переменная
ctBt:word;
ctShift:word;
CRC,CRC1:word;
flC:boolean;
loCRC,hiCRC,x:byte;
const
CRC_O:word=$61;
CRC_1:word=$A001;
begin
b[1]:=SID;
b[2]:=nomBlk;
b[3]:=kolBlk;
CRC:=CRC_O;
for ctBt:=1 to 3 do
begin
ctShift:=0;
CRC:=CRC xor b[ctBt];
repeat
if (CRC mod 2)>0 then flC:=true else flC:=false;
CRC:=CRC shr 1;
if flC then CRC:=CRC xor CRC_1;
ctShift:=ctShift+1;
until ctShift=8;
end;
result:=CRC;
end;
При разработке приложения для взаимодействия PC под W98,Xp и
т.п. следует учесть, что мах быстродейсвия можно добиться не
более чем 3..5 транзакций/сек (при худшем варианте)

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Вася Пупкин (2003-12-03 01:07) [5]

И в догонку к сказанному -)
http://www.modicon.com/techpubs/toc7.html
http://www.modicon.com/techpubs/crc7.html

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revo (2003-12-03 08:55) [6]

Большое спасибо всем !!!

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