Simatic CPU315-DP2: Use memory of micorcard

Due to lack of memory for all my DBs,is it possible to use the memory of the microcard? So I can acces a DB range here with the PLC.
I have a lot of parameter settings stored in DBs, which can be altered by the customer. Now I want a mirror range of these DBs so the customer can restore the original parameters when they want.

Or do I have buy the CPU317? What's then the need of buying a larger memory card? Just for backup the project? The current size is my project is now app.20mb (thanks to WINCC-Flexible2005)

Tnx

Hi,
yes you can buy a MMC and then to store some DBs in MMC and not in RAM.
I don't know much about CPU315, but if you can place in your PLC MMC then you can do this

See the manual(SFC_e.pdf - in google or at siemens www) to SFC or just help in Step7. I think it is SFC20 or 21 or 22 or... but you will find it easily.

Hello MAchinery;

I think the manual Martin refers to is the "System and Standard functions" pdf, available on the net opr on your computer if you have Step 7 installed (in the Simatics/Documentation directory).

The SFCs used to create, read from and write to a DB in load memory (your MMC card) are SFC82, 83 and 84.

Hope this helps,
Daniel Chartier

These seems the right SFCs thanks, but my purpose is that I want to read and write to a range of DBs in the load memory(MMC) by using only one
scratch DB in the work memory. This way it saves me work memory for my program control.
Now it looks like I have the range DBs in both the memories.
Examle: load memory DB[101..199] length 1kb
collect DB... into work memory DB100.
Thanks, Machinery

You don't have to create the DBs using SFCs. These can be created using normal techniques when you build your project offline. However each DB has a property called 'unlinked'. If a DB is unlinked it will only be loaded in to load memory when you download the program. It will not be copied in to work memory automatically at start up. It will still be accessible at runtime by using an appropriate SFC to copy the information in to work memory.
So your plan to have several unlinked DBs in load memory and just one in work memory is quite common. This is often used for recipe data or process or machine parameters.

Regards

Ken

Fixed it, thanks guys.
Only the structure of the DBs are gone, so an upload isn't possible. But that is not a problem, I'm only interested in the values.
Again thanks.