SFC84 use

Hello everyone,

I have been programming for two years but nothing difficult, now that I do something a little more advanced I'm having difficulties.

I am writing a small program on a S7 300 (315-2DP) to log date and input values each time there's a change on its inputs and every 5 seconds. I need a lot of space to store these, thus I need to store this data on DB on the MMC. 
Here is my problem, I cannot figure out how to use the SFC84 to move DB to the MMC. I would need to use indirect addressing of DB's but any solution is welcome. I've tried many thing and my latest attempt returns me the 7002 error. I thought this error would still allow the copy of data but when I check the block is still empty.
Maybe I'm doing something very wrong, maybe I'm missing something obvious but I cannot seem to find it.

If someone has a visually precise explanation of how to use this SFC 84 or other solution, I will take it gladly.

I thank you in advance for your response

Adrien

Hello adriena,

see the informations of the FAQs:

How do you parameterize blocks, which have "ANY"-type or "Pointer" type parameters?
https://support.industry.siemens.com/cs/ww/en/view/20443243

Why can't I see the values which are transmitted to an unlinked destination DB with SFC84, even though SFC84 is not indicating an error (RET_VAL = W#16#000?
https://support.industry.siemens.com/cs/ww/en/view/21688777

With best regards
Cicero