Rockwell-automation 1771-DMC_DMC1_DMC4_DXPS Control Coprocessor User M Bedienungsanleitung PDF herunterladen (Seite 254)

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Appendix B

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B-123

This function locks the requested TAG memory area.

C Syntax

#include <copro.h>

unsigned TAG_LOCK (tag,timeout)

unsigned tag;

char *tag;

unsigned timeout;

Parameters

tag

Use to access the TAG table. This can be either the symbolic TAG or

the handle returned from a TAG_LINK or TAG_DEFINE call.

timeout

Timeout value in seconds, from 0 to 16,383. A value of CC_FOREVER

(defined in COPRO.H) will wait until the TAG has been locked.

Returns

Value Symbolic Name Meaning



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  &-$" +"%',+ -$,

  " &'+ '%($+ "& +"%  $'#

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Description

Use the TAG_LOCK function to protect against concurrent access to the

tagged data when accessing the TAG without using TAG_READ or

TAG_WRITE.

Important: After access to the TAG is completed, you must call

TAG_UNLOCK to unlock the TAG; otherwise, the system may hang.

A status of CC_SUCCESS indicates that the calling procedure has locked

the TAG.

TAG_LOCK

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Rockwell-automation 1771-DMC_DMC1_DMC4_DXPS Control Coprocessor User M Bedienungsanleitung Seite 254