Siemens SCL Programming Upgraded Version: 12 Industrial Practical Cases

FUNCTION_BLOCK FB_MotorControl  

VAR_INPUT  
    StartButton: BOOL;  
    StopButton: BOOL;  
    OverloadSignal: BOOL;  
END_VAR  

VAR_OUTPUT  
    RunningStatus: BOOL;  
    FaultIndicator: BOOL;  
END_VAR  

BEGIN  
    // Start-Stop Logic  
    IF StartButton AND NOT StopButton AND NOT OverloadSignal THEN  
        RunningStatus := TRUE;  
    ELSIF StopButton OR OverloadSignal THEN  
        RunningStatus := FALSE;  
    END_IF;  


    // Fault Indication  
    FaultIndicator := OverloadSignal;  
END_FUNCTION_BLOCK  

FUNCTION_BLOCK FB_DelayStart  

VAR_INPUT  
    StartSignal: BOOL;  
    DelayTime: TIME := T#5S;  
END_VAR  

VAR_OUTPUT  
    OutputSignal: BOOL;  
END_VAR  

VAR  
    DelayTimer: TON;  
END_VAR  

BEGIN  
    DelayTimer(IN := StartSignal, PT := DelayTime);  
    OutputSignal := DelayTimer.Q;  
END_FUNCTION_BLOCK  

FUNCTION_BLOCK FB_TempControl  

VAR_INPUT  
    Setpoint: REAL;  
    ProcessValue: REAL;  
END_VAR  

VAR_OUTPUT  
    ControlOutput: REAL;  
END_VAR  

VAR  
    Kp: REAL := 2.0;  
    Ki: REAL := 0.05;  
    Kd: REAL := 0.5;  
    IntegralTerm: REAL := 0;  
    LastError: REAL := 0;  
    Timer: TON;  
END_VAR  

BEGIN  
    // Execute periodically (100ms)  
    Timer(IN := NOT Timer.Q, PT := T#100ms);  
    IF Timer.Q THEN  
        VAR Error := Setpoint - ProcessValue;  
        IntegralTerm := IntegralTerm + Error;  
        VAR DerivativeTerm := Error - LastError;  
        LastError := Error;  


        ControlOutput := Kp * Error + Ki * IntegralTerm + Kd * DerivativeTerm;  
        ControlOutput := LIMIT(0.0, ControlOutput, 100.0);  


        Timer(IN := FALSE);  
    END_IF;  
END_FUNCTION_BLOCK  

FUNCTION_BLOCK FB_ProductionQueue  

VAR_INPUT  
    NewOrder: BOOL;  
    OrderID: INT;  
    CompleteSignal: BOOL;  
END_VAR  

VAR_OUTPUT  
    CurrentOrder: INT;  
    QueueLength: INT;  
END_VAR  

VAR  
    OrderQueue: ARRAY[1..50] OF INT;  
    QueueHead: INT := 1;  
    QueueTail: INT := 1;  
END_VAR  

BEGIN  
    // New order enqueue  
    IF NewOrder AND QueueLength < 50 THEN  
        OrderQueue[QueueTail] := OrderID;  
        QueueTail := QueueTail MOD 50 + 1;  
        QueueLength := QueueLength + 1;  
    END_IF;  


    // Completed order dequeue  
    IF CompleteSignal AND QueueLength > 0 THEN  
        QueueHead := QueueHead MOD 50 + 1;  
        QueueLength := QueueLength - 1;  
    END_IF;  


    // Current order  
    IF QueueLength > 0 THEN  
        CurrentOrder := OrderQueue[QueueHead];  
    ELSE  
        CurrentOrder := 0;  
    END_IF;  
END_FUNCTION_BLOCK  

FUNCTION_BLOCK FB_SafetyGate  

VAR_INPUT  
    Gate1Closed, Gate2Closed: BOOL;  
    EStopButton: BOOL;  
    ResetButton: BOOL;  
END_VAR  

VAR_OUTPUT  
    SafetyStatus: BOOL;  
END_VAR  

VAR  
    LockoutStatus: BOOL := FALSE;  
    LockoutTimer: TON;  
END_VAR  

BEGIN  
    // Safety condition  
    VAR AllGatesClosed := Gate1Closed AND Gate2Closed;  


    // Emergency stop highest priority  
    IF EStopButton THEN  
        SafetyStatus := FALSE;  
        LockoutStatus := TRUE;  
        LockoutTimer(IN := TRUE, PT := T#10S);  
        RETURN;  
    END_IF;  


    // Unlock logic  
    IF ResetButton AND LockoutStatus AND LockoutTimer.Q THEN  
        LockoutStatus := FALSE;  
    END_IF;  


    // Normal operation  
    IF NOT LockoutStatus THEN  
        SafetyStatus := AllGatesClosed;  
    END_IF;