Morning Jesper!
Well I've repeated your test in post 30 and can pretty well confirm the same results - with one major oddity!
I created a new DB for the test and modified my programm a bit to use more data in more places, Merker as well as DBs.
I then loaded the whole program, actually to be precise the whole Station and started it.
Once again I set a bit in OB100 so as to cause the whole program to be bypassed until I clear the bit in the VAT. So I had a look at the initial values before letting the program run through the active part and noticed that both the old and the new DB, although both created with non-zero values were initialised to zero - as was the case yesterday. At a later stage, after trying a few other things, I decided to create another new DB, in order to try reading the stored value of the original DBs from the MMC using SFC83.
Once again I initialised it with a non-zero value, then stored and downloaded it from within the STL editor and guess what, when I go back to my VAT, there's my Initial Value still there!
So I went back to Simatic Manager and highlighted the "Blocks" folder and downloaded everything another look at the VAT and sure enough, the original two DBs still zero, but the third one, initially downloaded from the editor, still has its Initial value. Try again highlighting the "Station" folder download everything again, including all the Station parameters - no change.
Net result, If I create a DB and store it after editing, then download from Simatic Manager, the Initial Value is changed to Zero. If I create a DB and download it directly from the editor, the Initial Value is preserved - for ever. Most peculiar!
One of the other things I tried was to remove one memory card while the CPU was running and then replaced it with another and copy the same program down to the new card. But it didn't matter whether I power down without stopping or go into STOP first before swapping the cards back, the CPU always notices the change of card and does a memory reset - not too surprising really, I suppose.
I think we've about covered everything here now, with one exception - I've got three weeks of holiday over Christmas, so I'll run the program before I leave and power down. When I come back three weeks later, maybe we can find out definitively whether or not the Merker are saved on the MMC or not!