S7 Stl Help - Negated Nested Expressions lol

STL??? · Aug 8, 2011

Hi,
I'm trying to convert a Step7 program to ladder, i keep coming across nested expressions with a negated start.

Berger's paragraph explanation does nothing unfortunately to clear the fog as usual.

I've attached a simple example which i hope someone can help me with which doesn't convert.

Code:

AN(   
      A     #PartsPresent
      A     #LocksOn
      O     
      A     #NoPartsPresent
      A     #LocksOff
      )     
      R     #loadingOk

i interpret this to be

Code:

A(   
      An     #PartsPresent
      An     #LocksOn
      O     
      An     #NoPartsPresent
      An     #LocksOff
      )     
      R     #loadingOk

Is this right? the nesting is redundant i think also.

Thanks as always.

TurpoUrpo · Aug 8, 2011

No, it would be:

Code:

A( 
ON       #PartsPresent
ON       #LocksOn
)
A( 
ON       #NoPartsPresent 
ON       #LocksOff            
)
R     #loadingOk

But, you can just use:

Code:

--|NOT|--

To negate.

Code:

--||--||----|NOT|--()
         |
         |
--||--||--

STL??? · Aug 8, 2011

Got it - thanks TurpoUrpo

S7 Stl Help - Negated Nested Expressions lol

STL???

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