Dear,

I am facing problem in the memory area.

First pl. let me know what does the L means. I couldnot find this area in any FC's. I have alot of FC's which are calling from OB and some are calling from some other FC's.

But the strange thing is If i go online with any FC, and check the L area which in mentioned in the program coding ( When I view in STL) but in the FBD and LAD it is not showing.

Question is:-

I check in STL view and online, the memory area which is assigned for exampl

A   I.0

= L 1.0

A1.1

=L1.1

Upper mentioned example shows the L area. But sometimes the L area address is changed by itself . How does it possible?

Hello.

Mr. Chartier already mentioned theoretical background. Attached here is a page which also have some background.

[manual]

The L stack saves the following:
• The temporary variables of the local data of blocks
• The start information of the organization blocks
• Information about transferring parameters
• Interim results of the logic in Ladder Logic programs

 
You will see L bits popping up when converting LAD code to STL.This is the last piece mentioned in the above quote.

The following scenario is as example of what is happening. Network 2 represents the STL code to which the compiler converts to.

The compiler 'moves' the bit to try and prevent clashes with existing TEMP variables.

Dear #DP,

As you mentiond very clearly andi got the answer of my question [snip]