Sample program for CRC calculation

Dear Experts,

                            Is there is any standard block for CRC calculation. 

                             Or any other sample program for CRC calculation. 

Am using TIA v14 Software .

Kindly help this .

Regards,

Arasan.. 

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Split from S7-1200 PLC rs-232 Communication.

 Dear HUggy_d1,

                                   I have searched in Siemens forum and google also . There is no clear CRC calculation program . I ll not get any program too . If anyone previously have program and sample code for this . 

 Kindly share to here its very helpful for me .

Thanks and Regards,

Arasan.

huggy_d1

In these forums, you can search for CRC function block and web sites for calculating CRCs.

You can also google / web search for CRC calculation algorithms. 

Arasan

Dear Experts,

                            Is there is any standard block for CRC calculation. 

                             Or any other sample program for CRC calculation. 

Am using TIA v14 Software .

Kindly help this .

Regards,

Arasan.. 

 

Which type CRC?

https://en.wikipedia.org/wiki/Cyclic_redundancy_check

 Hello,

          CRC -16 .

Regards,

Arasan..

#dP

Which type CRC?

https://en.wikipedia.org/wiki/Cyclic_redundancy_check

 

 

Hello.

Arasan

 Hello,

          CRC -16 .

Regards,

Arasan..

The link from huggy_d1 is good!!
The link also links to another posting that is more friendly for S7-1200 SCL -> https://support.industry.siemens.com/tf/ww/en/posts/42284/

Make sure to read all the posts in the topic.

BR

Dear Huggy_d1, 

                                yes . i seen that link . I will check and reply . 

Thank  you ,

Regards,

Arasan.

Hi!

I created my own little SCL code after reading this topic (I always wondered how CRC is done).

I'd be happy if any of the more experienced programmers out there could take a look at it!

@Arasan:

Maby you can use a scrap of it, it seems to work, I have no idea however if it's efficient :-/

Source_Code:

FUNCTION_BLOCK "CRC_3_8_16"
{ S7_Optimized_Access := 'TRUE' }
VERSION : 0.1
VAR
"mess-3" { ExternalAccessible := 'False'; ExternalVisible := 'False'; ExternalWritable := 'False'} : Array[0..99] of Char;
w_3 { ExternalAccessible := 'False'; ExternalVisible := 'False'; ExternalWritable := 'False'} : Word;
w_8 : Word;
dw_16 : DWord;
i { ExternalAccessible := 'False'; ExternalVisible := 'False'; ExternalWritable := 'False'} : Int;
j { ExternalAccessible := 'False'; ExternalVisible := 'False'; ExternalWritable := 'False'} : Int;
crc_3 { ExternalAccessible := 'False'; ExternalVisible := 'False'; ExternalWritable := 'False'} : Byte;
crc_8 : Byte;
crc_16 : Word;
END_VAR

VAR CONSTANT
k_3 : Word := 2#1001000000000000;   // Key - CRC-3
k_8 : Word := 2#1001010110000000;   // Key - CRC-8
k_16 : DWord := 2#10010011001110011000000000000000;   // Key - CRC-16
END_VAR


BEGIN
IF true THEN
REGION CRC - 3

#w_3.%B1 := #"mess-3"[0];
FOR #i := 1 TO 99 DO
IF #"mess-3"[#i] = ' ' THEN
EXIT;
END_IF;
#w_3.%B0 := #"mess-3"[#i];
FOR #j := 0 TO 7 DO
IF #w_3.%X15 = 0 THEN
#w_3 := SHL_WORD(IN := #w_3, N := 1);
ELSE
#w_3 := #w_3 XOR #k_3;
#w_3 := SHL_WORD(IN := #w_3, N := 1);
END_IF;
END_FOR;
END_FOR;
FOR #j := 0 TO 7 DO
IF #w_3.%X15 = 0 THEN
#w_3 := SHL_WORD(IN := #w_3, N := 1);
ELSE
#w_3 := #w_3 XOR #k_3;
#w_3 := SHL_WORD(IN := #w_3, N := 1);
END_IF;
END_FOR;

#w_3 := SHR_WORD(IN := #w_3, N := 5);
#crc_3 := #w_3.%B1;

END_REGION

REGION CRC - 8

#w_8.%B1 := #"mess-3"[0];
FOR #i := 1 TO 99 DO
IF #"mess-3"[#i] = ' ' THEN
EXIT;
END_IF;
#w_8.%B0 := #"mess-3"[#i];
FOR #j := 0 TO 7 DO
IF #w_8.%X15 = 0 THEN
#w_8 := SHL_WORD(IN := #w_8, N := 1);
ELSE
#w_8 := #w_8 XOR #k_8;
#w_8 := SHL_WORD(IN := #w_8, N := 1);
END_IF;
END_FOR;
END_FOR;
FOR #j := 0 TO 7 DO
IF #w_8.%X15 = 0 THEN
#w_8 := SHL_WORD(IN := #w_8, N := 1);
ELSE
#w_8 := #w_8 XOR #k_8;
#w_8 := SHL_WORD(IN := #w_8, N := 1);
END_IF;
END_FOR;

#crc_8 := #w_8.%B1;

END_REGION

REGION CRC - 16

#dw_16.%B3 := #"mess-3"[0];
#dw_16.%B2 := #"mess-3"[1];
#dw_16.%B1 := #"mess-3"[2];

FOR #i := 3 TO 99 DO
IF #"mess-3"[#i] = ' ' THEN
EXIT;
END_IF;
#dw_16.%B0 := #"mess-3"[#i];
FOR #j := 0 TO 7 DO
IF #dw_16.%X31 = 0 THEN
#dw_16 := SHL_DWORD(IN := #dw_16, N := 1);
ELSE
#dw_16 := #dw_16 XOR #k_16;
#dw_16 := SHL_DWORD(IN := #dw_16, N := 1);
END_IF;
END_FOR;
END_FOR;
FOR #j := 0 TO 23 DO
IF #dw_16.%X31 = 0 THEN
#dw_16 := SHL_DWORD(IN := #dw_16, N := 1);
ELSE
#dw_16 := #dw_16 XOR #k_16;
#dw_16 := SHL_DWORD(IN := #dw_16, N := 1);
END_IF;
END_FOR;

#crc_16 := #dw_16.%W1;

END_REGION
END_IF;
END_FUNCTION_BLOCK

END_Source_Code