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博图TIA中ModbusRTU_CRC校验程序的实现

使⽤SCL语⾔，在博图TIA中编写ModbusRTU_CRC校验程序，使⽤两个FC块，实现两种不同的应⽤CRC1将计算结果直接输出,CRC2将计算的结果插⼊到输⼊数组的最后端. TIA中⾃带了modbusRTU通讯库，之所以⾃⼰实现CRC校验码的计算只是为了更深⼊的学习TIA SCL编程序.

实现效果及代码截图

代码⽚段

CRC1

FUNCTION "CRC1" : Void

{ S7_Optimized_Access := 'TRUE' }

VERSION : 0.1

VAR_INPUT

CrcData : Variant;

END_VAR

VAR_OUTPUT

CrcValue : Word;

CrcErr : Word;

END_VAR

VAR_TEMP

Preset : Word;

LoopLength : Int;

ArrayPoint : Int;

i : Int;

ArrayLength : UDInt;

Array1 : Array[0..999] of Byte; // 最多1000个字节

Err : Int;

END_VAR

BEGIN

#ArrayLength:= CountOfElements(#CrcData);

IF #ArrayLength <= 1000 THEN //这⾥的1000如果需要调⼤，对应的数组临时变量Array1也要调⼤

夹皮沟金矿#Err := MOVE_BLK_VARIANT(SRC := #CrcData, COUNT := #ArrayLength, SRC_INDEX := 0, DEST_INDEX := 0, DEST => #Array1);

#Preset := 16#FFFF;

#LoopLength := 0;

#ArrayPoint := 0;

//计算CRC校验码

WHILE #LoopLength < #ArrayLength DO //数据长度

#Preset := #Preset XOR #Array1[#ArrayPoint];

#ArrayPoint := #ArrayPoint + 1;

FOR #i := 0 TO 7 DO

IF (#Preset AND 16#01) = 16#01 THEN

#Preset := SHR(IN := #Preset, N := 1);

#Preset := #Preset XOR 16#A001;

ELSE

#Preset := SHR(IN := #Preset, N := 1);

END_IF;

END_FOR;

#LoopLength := #LoopLength + 1;

END_WHILE;

//#CrcValue := #Preset;

#CrcValue := SHR_WORD(IN := #Preset, N := 8) + SHL_WORD(IN := #Preset, N := 8);

#CrcErr := 16#0000;

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#CrcErr := 16#8000;

END_IF;

END_FUNCTION

SEND1

DATA_BLOCK "SEND1"

{ S7_Optimized_Access := 'FALSE' }

VERSION : 0.1

NON_RETAIN

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STRUCT

CrcData : Array[0..5] of Byte; // 该数组不⼤于1000字节

CrcValue : Word;

CrcError : Word;

END_STRUCT;

BEGIN

CrcData[0] := 16#01;

CrcData[1] := 16#03;

CrcData[2] := 16#00;

CrcData[3] := 16#00;

CrcData[4] := 16#00;

CrcData[5] := 16#01;

END_DATA_BLOCK

CRC2

FUNCTION "CRC2" : Void

{ S7_Optimized_Access := 'TRUE' }

VERSION : 0.1

VAR_INPUT

Command : Variant;

dataLen : Int;

END_VAR

VAR_TEMP

buffer : Array[0..#MaxLen] of Byte;

i : Int;

j : Int;

CrcReg : Word;

Len : Int;

END_VAR

VAR CONSTANT

MaxLen : Int := 255;

END_VAR

BEGIN

IF #dataLen = 0 OR #dataLen > CountOfElements(IN := #Command) - 2 THEN RETURN;

ELSE

#Len := #dataLen;

END_IF;

#CrcReg := 16#FFFF;

可爱的四兄弟//将数据转到缓冲区

VariantGet(SRC:=#Command,

DST=>#buffer);

/计算CRC校验码

FOR #i := 0 TO (#Len - 1) DO

#CrcReg := #CrcReg XOR #buffer[#i];

FOR #j := 0 TO 7 DO

杭州卷烟厂IF (#CrcReg AND 16#1) = 1 THEN

#CrcReg := SHR_WORD(IN := #CrcReg, N := 1);

#CrcReg := #CrcReg XOR 16#A001;

ELSE

#CrcReg := SHR_WORD(IN := #CrcReg, N := 1);

END_IF;

END_FOR;

#buffer[#Len + 1] := SHR_WORD(IN := #CrcReg, N := 8);

#buffer[#Len] := #CrcReg AND 16#FF;

//将缓冲区数据再写⼊到指针所指向的区域

VariantPut(SRC := #buffer,

DST := #Command);

END_FUNCTION

SEND2

DATA_BLOCK "SEND2"

{ S7_Optimized_Access := 'FALSE' }烫贴

VERSION : 0.1

NON_RETAIN

STRUCT

CrcData : Array[0..7] of Byte; // 该数组不⼤于1000字节

END_STRUCT;

BEGIN

CrcData[0] := 16#01;

CrcData[1] := 16#03;

CrcData[2] := 16#00;

CrcData[3] := 16#00;

CrcData[4] := 16#00;

CrcData[5] := 16#01;

END_DATA_BLOCK

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