Correct
Also correct. When the PLC boots up, it copies everything in load memory to work memory, and then sets all the M/I/Q to 0 (except retentive values).
Some programs might keep running from work memory, but either way, you're right, don't do it. It's bad for the MMC, and it definitely isn't recommended.
Yes. A memory reset is basically the same thing as the PLC getting powered on. The Work memory is deleted, and then the project is copied off of the load memory again. This means that all DB values get set to their initial value, and all M/I/Q memory goes to 0.
Not sure about the 400. I know it does have at least a little bit of internal load memory and does not require a memory card, but I know it also has a few different kinds of memory cards to expand the load memory. they may react differently to a memory reset. I know at least one kind of S7 400 memory card is flash memory, which mostly behaves like the MMC for the 300.
