battery for new Cp315-2DP

Dear all.
In New Cp315-2DP have MMC, but It does't have battery. I don't know why don't need to use battery. MMC is load memmory, but if CPU is running, power off, RAM memmmory for Work memmory off, current data in Work memmory lost?.
If I use CP315-2DP, I should choose capacity of MMC memmory(MB)?. Thanks

Hi,
The newer (MMC) based CPU's no longer need Batterys as all values are written to the MMC on Power down. Then on Power up they are reloaded dependant on how you have the CPU set up ie retentive areas M's DB's etc. check your CPU properties on the current setup.

Hope this Helps

Stevo

As for MMC Size, It all depends on what you want to store on it-ie documentation + Program or just your program.

By default you need an MMC the same size or larger than the processor memory. If you want to save your project and documentation on the MMC (which is definitely desirable) then you need a 2 - 4 MB MMC depending on the size of your project.

In RSlogix500, when compile, it have memory size need, I don't know Siemens have program in Step7 or other can caculate Loading memory and working memmory need to use?
Thanks

To find out how much memory your program needs, right click on the Blocks sub-directory in Simatic Manager to open the context menu, then choose Properties. Under the rider Blocks you will find how much load and working memory your program needs as well as number of Blocks you have used.