Fixing TwinCAT 3 Problem: FB_FileOpen Busy, State Machine Issue

Question

I'm new to Beckhoff/TwinCAT and following tutorials. While making a simple event logger, I hit a snag: after using FB_FileOpen, its bBusy stays True. This jams my state machine in FILE_OPEN. Any ideas on what I messed up? Here's my code:

VAR 
    fbFileOpen : FB_FileOpen;
    fbFilePuts : FB_FilePuts;
    RisingEdge : R_TRIG;
    eWriteState : (If_Trigger_Detection,OpenFile_Trigger, OpenFile, WaitForTheEvent,     WriteFileTriggner, WriteFile, CloseFile, Error); 
    stEventWriteToFile: ST_Event;
    
    CsvString : T_MaxString;
    
END_VAR

RisingEdge(CLK:=TRUE);

CASE eWriteState OF
    If_Trigger_Detection:
        IF RisingEdge.Q THEN 
            eWriteState:=OpenFile_Trigger;
        END_IF 
 
    OpenFile_Trigger:
        fbFileOpen.bExecute := FALSE;
        fbFileOpen(sPathName:= 'C:\TwinCAT\Eventslog.txt',nMode:=FOPEN_MODEAPPEND OR FOPEN_MODETEXT,bExecute := TRUE);
        eWriteState:= OpenFile;
        
    OpenFile:
        fbFileOpen.bExecute := FALSE;
        IF fbFileOpen.bError THEN
            eWriteState := Error;   
                 
        ELSIF NOT fbFileOpen.bBusy AND fbFileOpen.hFile <>0 THEN 
            eWriteState:= WaitForTheEvent;
            
        END_IF
        
        
    WaitForTheEvent:
        //do nothing just wait
    
    WriteFileTriggner:
    CsvString := CreateCsvString (stEvent:= stEventWriteToFile);
    //fbFilePuts(bExecute:=FALSE,
    //          sLine:=CsvString);
    fbFilePuts.bExecute:=FALSE;
    fbFilePuts(sLine := CsvString,bExecute := TRUE); 
    eWriteState := WriteFile;
    WriteFile:
    fbFilePuts(bExecute := FALSE);
    IF NOT fbFilePuts.bBusy THEN 
        eWriteState := WaitForTheEvent;
    END_IF

    //CloseFile:
    
    Error:
    //Here we will write the code for error Handling
END_CASE

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Answer 1

You have to keep calling fbFileOpen() also in the OpenFile-state. Right now you're only setting the bExecute-flag to FALSE, but you're not actually calling the body of the function block, which means it is never executed, and thus stays in busy. Simply replace:

fbFileOpen.bExecute := FALSE;

with

fbFileOpen(bExecute := FALSE);

Also, this question has already been answered here: TwinCAT 3: Write to File