Change log for Z tables when logging in not by the system.

the folowing are the steps tat i followed.

1) created CHANGE DOCUMENT OBJECT VIA SCDO. (OBJECT NAME : Z_test)

2) I have written the following code in  Z-TABLE ( ZSC_TEST) i.e IN SM30 by creating a module in PAI.

problem : am i in the ryt direction for creating logs ? if yes? there is excution problem .

   MODULE TEST INPUT.

DATA: OBJECTID                TYPE CDHDR-OBJECTID,
      TCODE                   TYPE CDHDR-TCODE,
      PLANNED_CHANGE_NUMBER   TYPE CDHDR-PLANCHNGNR,
      UTIME                   TYPE CDHDR-UTIME,
      UDATE                   TYPE CDHDR-UDATE,
      USERNAME                TYPE CDHDR-USERNAME,
      CDOC_PLANNED_OR_REAL    TYPE CDHDR-CHANGE_IND,
      CDOC_UPD_OBJECT         TYPE CDHDR-CHANGE_IND VALUE 'U',
      CDOC_NO_CHANGE_POINTERS TYPE CDHDR-CHANGE_IND.


* declaration for the long text
DATA: BEGIN OF ICDTXT_Z_TEST OCCURS 20.
        INCLUDE STRUCTURE CDTXT.
DATA: END OF ICDTXT_Z_TEST.
DATA: UPD_ICDTXT_Z_TEST TYPE C.

* table with the NEW content of: ZSC_TEST
DATA: BEGIN OF XZSC_TEST OCCURS 20.
        INCLUDE STRUCTURE YZSC_TEST.
DATA: END OF XZSC_TEST.

* table with the OLD content of: ZSC_TEST
DATA: BEGIN OF YZSC_TEST OCCURS 20.
        INCLUDE STRUCTURE YZSC_TEST.
DATA: END OF YZSC_TEST.

DATA: UPD_ZSC_TEST TYPE C.

  DATA : FZ_EMP TYPE ZSC_TEST. " INTERNAL TABLE OF ZTABLE
  DATA : FZ_CDTXT TYPE CDTXT.  " INTERNAL TABLE OF CDTXT
  DATA : T_CDTXT LIKE STANDARD TABLE OF FZ_CDTXT. "TABLE

BREAK-POINT.
  FZ_EMP-EQUNR    = ZSC_TEST-EQUNR .
  FZ_EMP-LOEVM_KO = ZSC_TEST-LOEVM_KO .
  FZ_EMP-KUNNR =  ZSC_TEST-KUNNR .
*  INSERT ZSC_TEST FROM FZ_EMP.
  APPEND fz_emp to ICDTXT_Z_TEST .
*  APPEND ICDTXT_Z_TEST .
  APPEND fz_emp to XZSC_TEST.
  APPEND fz_emp to YZSC_TEST.

  UPD_ICDTXT_Z_TEST = 'I'.

  BREAK-POINT.
*  IF   ( UPD_ZSC_TEST NE SPACE )
*    OR ( UPD_ICDTXT_Z_TEST NE SPACE )
*  .
*    CALL FUNCTION 'SWE_REQUESTER_TO_UPDATE'.
    CALL FUNCTION 'Z_TEST_WRITE_DOCUMENT'  "IN UPDATE TASK
        EXPORTING
          OBJECTID                = OBJECTID
          TCODE                   = sy-TCODE
          UTIME                   = sy-uzeit
          UDATE                   = sy-datum
          USERNAME                = sy-uname
          PLANNED_CHANGE_NUMBER   = ' ' "PLANNED_CHANGE_NUMBER
          OBJECT_CHANGE_INDICATOR = 'I' "CDOC_UPD_OBJECT
          PLANNED_OR_REAL_CHANGES = ' ' "CDOC_PLANNED_OR_REAL
          NO_CHANGE_POINTERS      = ' '"CDOC_NO_CHANGE_POINTERS
* updateflag of ZSC_TEST
          UPD_ZSC_TEST
                      = 'I'
          UPD_ICDTXT_Z_TEST
                      = 'I ' "UPD_ICDTXT_Z_TEST
        TABLES
          ICDTXT_Z_TEST
                      = ICDTXT_Z_TEST
          XZSC_TEST
                      = XZSC_TEST
          YZSC_TEST
                      = YZSC_TEST
    .
    if sy-subrc eq 0.
    message 'log created' type 'S'.
    else.
      message 'insert Error' type 'S'.
  ENDIF.
  CLEAR PLANNED_CHANGE_NUMBER.
ENDMODULE.