To use RFC /SCWM/HU_WEIGHT_FROM_SCALE from your own ABAP’s, firstly create a scale in transaction /SCWM/SCALE.

*&---------------------------------------------------------------------*
*& Report  ZTESTSCALE
*&
*&---------------------------------------------------------------------*
*&
*&
*&---------------------------------------------------------------------*

*&---------------------------------------------------------------------*
*& Report  ZTESTSCALE                                                  *
*&                                                                     *
*&---------------------------------------------------------------------*
*& Author: Pocket Programs 2013                                        *
*& =============================                                       *
*& Example ABAP for use with ERP-Scale see www.pocketprograms.com             *
*&                                                                     *
*&                                                                     *
*&---------------------------------------------------------------------*

REPORT  ZPP_TEST_ERPSCALE                            .

TABLES: sscrfields.

parameter: p_lgnum  type /SCWM/LGNUM." default 'TEST'.
parameter: p_packst type /SCWM/DE_SCALE_ID." default 'TEST'.
* Declaration of sel screen buttons
SELECTION-SCREEN BEGIN OF LINE.
SELECTION-SCREEN PUSHBUTTON (30) w_button USER-COMMAND BUT1.
SELECTION-SCREEN END OF LINE.
parameter: p_weight(20). "MODIF ID DSP.
parameter: p_unit(20) DEFAULT 'KG' lower case. "MODIF ID DSP.
parameter: p_text(20) lower case."MODIF ID DSP.
parameter: p_dummy1(20) lower case. "MODIF ID DSP .
parameter: p_dummy2(20) lower case."MODIF ID DSP.
selection-screen SKIP.
parameter: p_rc(6)  MODIF ID DSP.
parameter: p_msg(220) lower case MODIF ID DSP.

data: gs_profile type /SCWM/TWORKST.
data gs_scale type /scwm/scale.

data: lt_weight type table of /scwm/s_hu_scale,
      ls_weight type /scwm/s_hu_scale,
      MSG_TEXT(120) TYPE C, "Message text
      L_RFC_DESTINATION LIKE RFCDISPLAY-RFCDEST.
data: l_weight type /SCWM/BRGEW.

*=================================================
initialization.

* Make result fields read-only
  LOOP AT SCREEN.
    IF SCREEN-GROUP1 = 'DSP'.
      SCREEN-INPUT = 0.
      MODIFY SCREEN.
    ENDIF.
  ENDLOOP.
* Add displayed text string to buttons
  w_button = 'Get weight using ERP-Scale'.
* Determine packing station profile from PC hostname
  perform read_workstation.
  p_packst = gs_profile-workstation.
  p_lgnum = gs_profile-lgnum.

*================================================
AT SELECTION-SCREEN.
* Check if button has been pressed
  if sscrfields-ucomm eq 'BUT1'.
     perform do_weighing.
  endif.
*=================================================
FORM do_weighing.
    perform read_profile using p_lgnum p_packst.
* rfc-destination aus Customizing:
    l_rfc_destination = gs_scale-SCALE_RFC.
    ls_weight-scale_name = gs_scale-SCALE.

    if l_rfc_destination is initial.
      clear: p_weight, p_unit, p_text, p_dummy1, p_dummy2.
      message e203(hudialog) with l_rfc_destination.
    endif.
* Function module must be called with at least one
* entry in the table
    ls_weight-g_weight   = p_weight.
    ls_weight-unit_gw    = p_unit.
    ls_weight-text       = p_text.
    ls_weight-scale_id   = p_dummy1.
    ls_weight-weight_cnt = p_dummy2.
    refresh lt_weight.
    append ls_weight to lt_weight.

    clear: p_msg, p_rc.

    CALL FUNCTION '/SCWM/HU_WEIGHT_FROM_SCALE' destination l_rfc_destination
      TABLES
        ET_WEIGHT             = lt_weight
      EXCEPTIONS "<< begin note 205878
        COMMUNICATION_FAILURE = 1  MESSAGE MSG_TEXT
        SYSTEM_FAILURE        = 2  MESSAGE MSG_TEXT
        OTHERS                = 5.


    p_rc = sy-subrc.

    if not sy-subrc is initial.
      p_msg = msg_text.
    endif.

    if not sy-subrc is initial.
      concatenate text-040 l_rfc_destination msg_text
                     into msg_text separated by space.
      message s001(vl) with msg_text.
      clear: p_weight, p_unit, p_text, p_dummy1, p_dummy2.
      return.
    endif.
    clear ls_weight.
    read table lt_weight into ls_weight index 1.
    if ls_weight-g_weight is initial.
      message e203(hudialog) with l_rfc_destination.
    endif.
    catch system-exceptions CONVT_NO_NUMBER = 9 .
      p_weight = ls_weight-g_weight.
    endcatch.
    if sy-subrc = 9.
      message s000(zz) with ls_weight.
    endif.
    "concatenate p_weight ls_weight-g_weight into p_msg separated by space.
*    message s000(zz) with p_msg.
    p_unit = ls_weight-unit_gw.
    p_text = ls_weight-text.
    p_dummy1 = ls_weight-scale_id.
    p_dummy2 = ls_weight-scale_name.
ENDFORM.
*==============================================================
at SELECTION-SCREEN OUTPUT.
* Make result fields read-only
  LOOP AT SCREEN.
    IF SCREEN-GROUP1 = 'DSP'.
      SCREEN-INPUT = 0.
      MODIFY SCREEN.
    ENDIF.
  ENDLOOP.
*==============================================================

START-OF-SELECTION.
  if sy-batch ne SPACE.
    perform do_weighing.
    concatenate p_weight ls_weight-unit_gw into p_msg separated by space.
    message s000(zld_conv) with 'ERP-Scale' 'returned' p_msg.
    exit.
  endif.

*&---------------------------------------------------------------------*
*&      Form  READ_PROFILE
*&---------------------------------------------------------------------*
*       text
*----------------------------------------------------------------------*
*  -->  p1        text
*  <--  p2        text
*----------------------------------------------------------------------*
FORM read_workstation.

  statics sf_terminal(20).
  DATA: lt_profile TYPE TABLE OF /SCWM/TWORKST.
* Get hostname from PC
  CALL FUNCTION 'TH_USER_INFO'
    IMPORTING
      terminal = sf_terminal.
* prerequisite there is only one profile per PC
  SELECT * FROM /SCWM/TWORKST CLIENT SPECIFIED INTO TABLE lt_profile
        WHERE terminal = sf_terminal AND mandt = sy-mandt.
  IF NOT sy-subrc IS INITIAL.
    EXIT.
  ENDIF.
  READ TABLE lt_profile TRANSPORTING NO FIELDS INDEX 2.
  IF sy-subrc IS INITIAL.
    EXIT.
  ENDIF.
  READ TABLE lt_profile INTO gs_profile INDEX 1.
* PERFORM set_profile.
ENDFORM.                    "read_packstation

*&---------------------------------------------------------------------*
*&      Form  READ_PROFILE
*&---------------------------------------------------------------------*
*       text
*----------------------------------------------------------------------*
*  -->  p1        text
*  <--  p2        text
*----------------------------------------------------------------------*
FORM read_profile using p_lg p_st.

  DATA: lt_profile TYPE TABLE OF /SCWM/TWORKST.
* prerequisite there is only one profile per PC
  SELECT * FROM /SCWM/TWORKST CLIENT SPECIFIED INTO TABLE lt_profile
        WHERE LGNUM = p_lg AND WORKSTATION = p_st AND mandt = sy-mandt.
  IF NOT sy-subrc IS INITIAL.
    EXIT.
  ENDIF.
  READ TABLE lt_profile TRANSPORTING NO FIELDS INDEX 2.
  IF sy-subrc IS INITIAL.
    EXIT.
  ENDIF.
  READ TABLE lt_profile INTO gs_profile INDEX 1.
* PERFORM set_profile.
* Read scale
  SELECT single * FROM /SCWM/SCALE CLIENT SPECIFIED INTO gs_scale
        WHERE scale = gs_profile-scale AND client = sy-mandt.



ENDFORM.                    "read_profile