Sample

The use of individual functions can look like this. In this sample, the ApplicationSpecificTag is written via Write and then read and checked via Read method.

FUNCTION_BLOCK FB_Sample_03_IolSlave
VAR_INPUT
    bExecute                : BOOL := FALSE;
    sApplicationTag         : STRING(32) := '';
END_VAR
VAR_OUTPUT
    bBusy                   : BOOL := FALSE;
    bDone                   : BOOL := FALSE;
    bError                  : BOOL := FALSE;
    nAdsError               : E_AdsErr := E_AdsErr.NOERR;
    nIolError               : E_IolError := E_IolError.NoError;
    sErrorTxt               : STRING(255) := '';
END_VAR
VAR
    bExecuteOld             : BOOL;
    nState                  : INT := 0;
    fbIolSlave              : FB_IolSlave;
    bInitDone               : BOOL := FALSE;
    hr                      : HRESULT;
    sApplicationTagRead     : STRING(32) := ''

END_VAR

////
// Init
//
IF NOT bInitDone THEN
    bInitDone := TRUE;
    fbIolSlave.MasterAoeNetId := F_CreateAmsNetId(GVL_IO.sTerm2AmsNetId);
    fbIolSlave.Port := GVL_IO.nTerm2EPI1008;
    fbIolSlave.Name := 'EPI1008';
END_IF

////
// Execute/Busy State Machine
//
IF bExecute AND NOT bExecuteOld AND NOT bBusy THEN
    bBusy := TRUE;
    nState := 10;    // WRITE
ELSIF NOT bExecute THEN
    bBusy := FALSE;
    bError := FALSE;
    bDone := FALSE;
    nAdsError := E_AdsErr.NOERR;
    nIolError := E_IolError.NoError;
    sErrorTxt := '';
END_IF
bExecuteOld := bExecute;

////
// FB State Machine
//
CASE nState OF
    
// IDLE
0:;

// WRITE
10:
    hr := fbIolSlave.Write(16#0018, 0, ADR(sApplicationTag), 32);
    
    IF NOT F_IolIsBusy(hr) THEN
        IF FAILED(hr) THEN
            bBusy := FALSE;
            bError := TRUE;
            sErrorTxt := fbIolSlave.ErrorTxt;
            nAdsError := F_IolGetAdsError(hr);
            nIolError := F_IolGetIolError(hr);
            nState := 0; // IDLE;
        ELSE
            nState := 20; // READ;
        END_IF
    END_IF
    
// READ
20:
    hr := fbIolSlave.Read(16#0018, 16#00, ADR(sApplicationTagRead), 32);
    
    IF NOT F_IolIsBusy(hr) THEN
        IF FAILED(hr) THEN
            bBusy := FALSE;
            bError := TRUE;
            sErrorTxt := fbIolSlave.ErrorTxt;
            nAdsError := F_IolGetAdsError(hr);
            nIolError := F_IolGetIolError(hr);
            nState := 0; // IDLE;
        ELSE
            nState := 30; // CHECK;
        END_IF
    END_IF
    
// CHECK
30:
    IF sApplicationTag <> sApplicationTagRead THEN
        bBusy := FALSE;
        bError := TRUE;
        sErrorTxt := 'sApplicationTag and sApplicationTagRead are not equal!';
    ELSE
        bBusy := FALSE;
        bDone := TRUE;
        nState := 0;
    END_IF
END_CASE

////
// call FBs
//
fbIolSlave();