CPU Replace with new Version

Hi YogendraG,

The best practice for replacing an older S7 CPU with a newer one, is to completely backup the MMC first, without removing the MMC from the CPU! My method is to create a new project and use the "Upload Station to PG" in SIMATIC Manager. If the CPU is defective and not accessible, then you need to read out the memory card using a Siemens USB Prommer (external MMC reader). Unfortunately, there ispossible loss of current values if the MMC is removed from the CPU, but if you have no choice but to remove it... you will have to re-enter them.

In principle, if Siemens declares a CPU to be "Spare Part Compatible", it means youshould simply be able to take the MMC out of the older CPU and place it into the new CPU with no changes to STEP 7 required. I've found from experiencethat after uploading from the old CPU, I usually had to download only my data blocks (DB's) (from thenewly uploaded backup project!)back to the new CPU to retain my "online" vaules.

The linkbelowdeclares the newer CPU to be"Spare Part Compatible" for your older CPU:

http://support.automation.siemens.com/WW/view/en/74785839

I hope this helps.

Shawn

Hi Yogendra,

I just read that this new CPU will be your spare... in that case, upload from the existing CPU, and download to your new CPU. I would highly recommend having asecond MMC in your spare, instead of relying on removing the existing MMC from the old CPU.

Your older CPU has an MMC, and I recommend your new CPU also have it's own MMC.

Regards,

Shawn