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(*

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 * (c) 26 Feb 2001 David Campbell

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 *

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 * Offered to the public under the terms of the GNU General Public License

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 * as published by the Free Software Foundation; either version 2 of the

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 * License, or (at your option) any later version.

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 *

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 * This program is distributed in the hope that it will be useful, but

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 * WITHOUT ANY WARRANTY; without even the implied warranty of

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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General

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 * Public License for more details.

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 *

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 * This code is made available on the understanding that it will not be

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 * used in safety-critical situations without a full and competent review.

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 *)

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(*

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 * An IEC 61131-3 IL and ST compiler.

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 *

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 * Based on the

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 * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)

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 *

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 *)

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(*

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 * This is part of the library conatining the functions

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 * and function blocks defined in the standard.

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 *

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 * SR and RS function blocks

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 * -------------------------

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 *)

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FUNCTION_BLOCK SR

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  VAR_INPUT

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    S1 : BOOL;

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    R  : BOOL;

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  END_VAR

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  VAR_OUTPUT

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    Q1 : BOOL;

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  END_VAR

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  VAR

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    Q_INTERNAL : BOOL;

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  END_VAR

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  Q_INTERNAL := S1 OR ( Q_INTERNAL AND (NOT R));

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  Q1 := Q_INTERNAL;

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END_FUNCTION_BLOCK

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FUNCTION_BLOCK RS

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  VAR_INPUT

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    S : BOOL;

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    R1 : BOOL;

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  END_VAR

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  VAR_OUTPUT

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    Q1 : BOOL;

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  END_VAR

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  VAR

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    Q_INTERNAL : BOOL;

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  END_VAR

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  Q_INTERNAL := (NOT R1) AND (S OR Q_INTERNAL);

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  Q1 := Q_INTERNAL;

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END_FUNCTION_BLOCK