I/O Drivers

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~~~ST

FUNCTION_BLOCK I2CTemplate EXTENDS i2c

VAR_INPUT

    lrMinDistance: LREAL;

    lrMaxDistance: LREAL;

END_VAR

VAR_OUTPUT

    lrDistance: LREAL;

    xValid: BOOL;

    xNewMeasurement: BOOL;

END_VAR

VAR

    timer: TON;

END_VAR

~~~

~~~ST

xNewMeasurement := FALSE;

SUPER^();

CASE _iState OF

0:

    IF usiAddress = 0 THEN

        usiAddress := 16#70;

    END_IF

    IF SUPER^.init() THEN

        _iState := 5;

    END_IF  

5:  

    Timer.pt := T#70MS;

    _iState := 10;  

    xValid := FALSE;

END_CASE

~~~

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~~~ST

METHOD AfterReadInputs: INT

VAR

    Buffer: ARRAY [..] OF ;

    len: DINT;

END_VAR

~~~

~~~ST

SUPER^.AfterReadInputs();

IF _iState = 10 THEN

    timer(IN:=TRUE);

    IF timer.Q THEN 

        len := Read(ADR(Buffer), 4);

        IF len = 4 THEN

            lrDistance := BYTE_TO_LREAL(Buffer[2])*0.01 + BYTE_TO_LREAL(Buffer[3]) * 2.56;

            xValid := (lrDistance >= lrMinDistance AND lrDistance <= lrMaxDistance);

            xNewMeasurement := TRUE;

        ELSE

            xValid := FALSE;

        END_IF

        Write8(0, 16#51);   //new measurement

        timer(IN:=FALSE);

    END_IF      

END_IF

~~~

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~~~ST

METHOD BeforeWriteOutputs: INT

~~~

~~~ST

SUPER^.BeforeWriteOutputs();

~~~