Why we do use more than one networks in Ladder logic of Siemens PLCs ?

Why we do use more than one networks in Ladder logic of Siemens PLCs ?

whats the need of using more than one networks in programming a task inside S 7 Simatic Manager of Siemens S7 PLCs in Ladder logic ?

thanks

Readability , maintanability, common sense, ...

Not Siemens but....

I worked on a program in RSLogix that was just under 600 rungs long all in the same file/network

It was a nightmare to work on, everyone (myself included) just added to it, it would take a month to clean it up and the plant manager would not give anyone the time to do it.

The case of Siemens Step7 (V5.4), each network can have its comment. This is convenient to maintain. And too large network is very hard to modify.

Also in step 7 each segment has the Authors name, date of creation, last modification date
stamped on it which makes it easier to see what has been modified, when and by whom.

Sorry lost the attachment, another try:

If you are faithful about commenting each network, when you collapse all the networks you can simply read the program flow by reading the comments. Its beautiful.
When I come back to a program months or years later I can quickly refresh myself on the program: its one of the nicest features of Siemens networks (instead of having to wade through hundreds of lines of ladder logic to understand the program).

There are also certain times (and certain processors) you have to use networks. For example, labels must be attached to a network so you can jump directly to that network.

There is a bit that gets set at the begin of each network. The S7 doesn't have a load bool so there is a boolean state bit that is and and the first instruction must use an and instruction.

It's very much the same reason as why we use punctuation, sentences and paragraphs when writing a text: readability and better understandability.

Kind regards,