VDA Modulus 43 method of Data Matrix ECC200

From time to time we all have to fulfill some technical norm. Concerning Data Matrix code ECC200 - VDA label norm there is no exception. Once I had to code this norm requirement, simple task to get security sign of all DMC content. So why to discover a wheel again? :) Check my approach below.

VDA requirement says

The check digit is calculated with the Modulus 43 method:

For this purpose the numeric values of all characters transferred (without control characters) are

added and the sum is divided by 43.

The remaining balance is converted into a character again and transferred in the data record as a

check digit. 

Example: the “12345ABCDE” string makes the check digit W. 1+2+3+4+5+10+11+12+13+14 = 75 

--> 75 : 43 = 1 Rest 32 -> 32 equals the W character.

I put some simple subroutine into SF to add one DataMatrix code item.

Later on subroutine for modulus 43.

The actual coding looks like this

*&---------------------------------------------------------------------*
*&      Form  get_check_code
*&---------------------------------------------------------------------*
*       get VDA security check character
*----------------------------------------------------------------------*
*      -->LV_INPUTDATA_STR  text
*      -->LV_CHECK_CHAR     text
*----------------------------------------------------------------------*
FORM get_check_code
      USING
          lv_inputdata_str TYPE string
      CHANGING
          lv_check_char    TYPE /fit/lwert.

  TYPES: BEGIN OF ty_translation,
            input TYPE c1,
            value TYPE i,
         END OF ty_translation.

  DATA: lt_translations TYPE STANDARD TABLE OF ty_translation,
        ls_translation LIKE LINE OF lt_translations.

  CONSTANTS cv_diviser TYPE i VALUE 43.

  ls_translation-input = '0'.
  ls_translation-value = 0.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = '1'.
  ls_translation-value = 1.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = '2'.
  ls_translation-value = 2.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = '3'.
  ls_translation-value = 3.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = '4'.
  ls_translation-value = 4.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = '5'.
  ls_translation-value = 5.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = '6'.
  ls_translation-value = 6.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = '7'.
  ls_translation-value = 7.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = '8'.
  ls_translation-value = 8.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = '9'.
  ls_translation-value = 9.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'A'.
  ls_translation-value = 10.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'B'.
  ls_translation-value = 11.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'C'.
  ls_translation-value = 12.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'D'.
  ls_translation-value = 13.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'E'.
  ls_translation-value = 14.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'F'.
  ls_translation-value = 15.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'G'.
  ls_translation-value = 16.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'H'.
  ls_translation-value = 17.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'I'.
  ls_translation-value = 18.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'J'.
  ls_translation-value = 19.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'K'.
  ls_translation-value = 20.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'L'.
  ls_translation-value = 21.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'M'.
  ls_translation-value = 22.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'N'.
  ls_translation-value = 23.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'O'.
  ls_translation-value = 24.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'P'.
  ls_translation-value = 25.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'Q'.
  ls_translation-value = 26.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'R'.
  ls_translation-value = 27.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'S'.
  ls_translation-value = 28.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'T'.
  ls_translation-value = 29.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'U'.
  ls_translation-value = 30.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'V'.
  ls_translation-value = 31.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'W'.
  ls_translation-value = 32.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'X'.
  ls_translation-value = 33.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'Y'.
  ls_translation-value = 34.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = 'Z'.
  ls_translation-value = 35.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = '-'.
  ls_translation-value = 36.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = '.'.
  ls_translation-value = 37.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = ' '.
  ls_translation-value = 38.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = '$'.
  ls_translation-value = 39.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = '/'.
  ls_translation-value = 40.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = '+'.
  ls_translation-value = 41.
  APPEND ls_translation TO lt_translations.

  ls_translation-input = '%'.
  ls_translation-value = 42.
  APPEND ls_translation TO lt_translations.
*
  TRANSLATE lv_inputdata_str TO UPPER CASE.

  DATA: lv_char   TYPE c,
        lv_offset TYPE syindex,
        lv_sum    TYPE i,
        lv_rest   TYPE i.

  " get sum of character values
  DO strlen( lv_inputdata_str ) TIMES.
    lv_offset = sy-index - 1.
    lv_char = lv_inputdata_str+lv_offset.

    IF lv_char IS NOT INITIAL.
      CLEAR ls_translation.
      READ TABLE lt_translations WITH KEY input = lv_char INTO ls_translation.
      IF sy-subrc EQ 0.
        lv_sum = lv_sum + ls_translation-value.
      ENDIF.
    ENDIF.
  ENDDO.

  " get proper 43 return code
  IF lv_sum NE 0.
    lv_rest = lv_sum MOD cv_diviser.
    CLEAR ls_translation.
    READ TABLE lt_translations WITH KEY value = lv_rest INTO ls_translation.
    IF sy-subrc EQ 0.
      lv_check_char = ls_translation-input.
    ENDIF.
  ENDIF.
ENDFORM.                    "get_check_code