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 FUNCTION_BLOCK AVERAGE

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   VAR_INPUT

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     RUN : BOOL ;      (* 1 = run, 0 = reset *)

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     XIN : REAL ;     (* Input variable *)

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     N   : INT ;      (* 0 <= N < 128 or manufacturer- *)

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   END_VAR            (*      specified maximum value  *)

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   VAR_OUTPUT XOUT : REAL ; END_VAR (* Averaged output *)

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   VAR SUM  : REAL := 0.0; (* Running sum *)

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       FIFO : DELAY ;      (* N-Element FIFO *)

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   END_VAR

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   SUM := SUM - FIFO.XOUT ;

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   FIFO (RUN := RUN , XIN := XIN, N := N) ;

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   SUM := SUM + FIFO.XOUT ;

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   IF RUN THEN XOUT := SUM/N ;

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   ELSE SUM := N*XIN ; XOUT := XIN ;

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   END_IF ;

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 END_FUNCTION_BLOCK

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