Difference between plc300 in pcs7 with TIA 1200

Even though Siemens has deemed me expert in all things TIA Portal, I'm not, especially when it relates to S7-300/400 PLCs, and especially some of the more advanced S7-1500 configurations, and the occasional hardware oddities available for S7-1200's.

That said.. in traditional S7-300/400 (classic step 7), the temp memory in shared and the compiler does not take that into consideration by detecting or warning you.

In TIA Portal, it is well aware temp memory is shared, and (here's where my expertise falls short) I think that the compiler is aware so it pre-configures temp memory to a 0 state for S7-300/400 - and preconfiguring temp tags to 0 is supported in hardware for s7-1200/1500.

Your findings seem to support my thoughts (which are not from experience or training).

Hopefully more well-rounded experts will speak up on the reality, or "the real story".

U_92de906d-8b39-4b34-a72d-85a2a877cc4a

Hello to all!

There is another difference between plc300 in pcs7 with TIA 1200, the program image is attached.

We created station 300 in pcs7 which includes FC with Fb _DB, when we modify input block for only a block, some memory bits of fc and Fb blocks are changed together.

It is very important that if someone builds these blocks and uses them, there will be interactivity that we can not find it. so may not be traceable and debugged in a large project.

Issue: executing the same command in a part of the block that has no memory connection with another block.

In this case,

When the "Start" input of one block is modified to TRUE, the "SR" of the other block is also activated! Why?

The program was simolation part of a project that is summarized in a new project.

This program on another laptop by the same pcs7 has similar results. we changed it to static type (for Fb) but the interaction between memories was yet.

But it works properly in Tia portal..

Why are those really related?

Thanks!