S5 AWL Commands: SET / CLR (VKE Control)

SET forces the VKE to TRUE. CLR forces the VKE to FALSE. Both are unconditional — they override any previous VKE state.

Syntax#

SET                 // VKE = TRUE
CLR                 // VKE = FALSE

S7 Equivalent#

Code Example#

SET                 // Force VKE = TRUE
=  A 4.0            // A 4.0 is unconditionally TRUE (always on)

CLR                 // Force VKE = FALSE
=  A 4.1            // A 4.1 is unconditionally FALSE (always off)

Typical Use#

• SET before S: Unconditionally set a bit: SET / S M 10.0
• CLR before =: Force an output off regardless of logic
• CLR to start a clean logic chain after complex operations

Note#

SET and CLR are rarely seen in well-written code. They are typically used for initialization, testing, or as workarounds. In SCL, the equivalent is simply output := TRUE; or output := FALSE;.

Part of the S5 AWL Command Reference. Maintained by PLCcheck.ai.

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