Size Of Block In Load Memory And Work Memory

Hello Friends,

The size of  FBs or FCs...etc will be less in work memory than the size in load memory.So what will be the difference?

Hi IZ ALJABRE-JORDAN,

The work memory of block is the amount of data of block while block is being executed by CPU. Remaining part of block is in work memory. Work memory is used by PLC CPU for processing of program and it can directly access it. Whereas Load memory is the where entire program is present after downloading.

Thank you for replying.

But can you please give an example? or suppose a i'm writing this code in FC1,so what will be loaded in the working memory and what will be there in loading memory.?

NW2

Hi IZ ALJABRE-JORDAN,

Step-7 documentation does not mention exactly what is there in load/work memory. Also note that user/programmer should not worry about it. Generally it is referred when CPU gives message'Work memory insufficient. Compression is required'. U can't download program in such situations.

Significance of the setting-When selecting PLC CPU, the entire work memory requirement can be known in advance if similar or actual program is available[Block properties-work memory]. This is most useful aspect of this setting. 

Thanks Mr.Sachinpatke. You are right. 

Hi 

Here is a link describing the Memory Concept. It does not Answer you first question, but gives an overview

https://support.industry.siemens.com/cs/us/en/view/7302549

BR. Sven

Thank you Mr.SMJE

But that is basic for me and well known.Actually i am searching for an advanced document,if you get it please help.

Thanks in advance.

Dear All,

                 Please go through the fallowing very good discussion about the memory concept.

https://support.industry.siemens.com/tf/gb/en/posts/memory-concept-doubt/96580/?page=0&pageSize=10