Dear All,

I have an s7 300 plc with a memory card ..But Now that PLC goes faulty .. Need to know if we insert the memory card from the faulty PLC to the new PLC will it work or not..??

Or any configuration required ??

Or memory card should contain a backup of PLC ??+

Normally if we download to PLC the project will be downloaded to a Memory card and from there only the CPU takes to my knowledge ..So if we swap the memory card means will it work?

I never experienced similar issues..Please guide me on this..

Hello kmansal;

Depending on the age of your S7-300 PLC, your memory card will either be a RAM or Flash EPROM: 6ES7-951-1..) MC: or an MMC (6ES7 853-8...). Examine the memory card that you have to determine what load memory type you are workig with, it will be written the type of memory card and its size in bytes.

You will find a description of the structure of the S7-300 memory. for he different generations of these PLCs, in the followig link:

How can you obtain an overview of the memory concept of SIMATIC S7-300 CPUs and C7 devices?

https://support.industry.siemens.com/cs/ww/en/view/7302326

If what you have is a RAM MC, then you are out of luck, the RAM chips require constant power from the CPU to maintain their memorized content and once the PLC is powered down everything on the MC wil be lost.

If you have a Flash EPROM MC or a MMC (and it fits in your new CPU, because they are of the same generation), then slotting the memroy card in the new PLC and powering it up  will transfer the content of the last download on the memory card to the new CPU memory: hardware and communication configuration, program blocks, system data etc...

Hope this helps,

Daniel Chartier

 Thanks for the nice useful and meaningfull explanation ..Let me check memory card type and will update back ..

dchartier

Hello kmansal;

Depending on the age of your S7-300 PLC, your memory card will either be a RAM or Flash EPROM: 6ES7-951-1..) MC: or an MMC (6ES7 853-8...). Examine the memory card that you have to determine what load memory type you are workig with, it will be written the type of memory card and its size in bytes.

You will find a description of the structure of the S7-300 memory. for he different generations of these PLCs, in the followig link:

How can you obtain an overview of the memory concept of SIMATIC S7-300 CPUs and C7 devices?

https://support.industry.siemens.com/cs/ww/en/view/7302326

If what you have is a RAM MC, then you are out of luck, the RAM chips require constant power from the CPU to maintain their memorized content and once the PLC is powered down everything on the MC wil be lost.

If you have a Flash EPROM MC or a MMC (and it fits in your new CPU, because they are of the same generation), then slotting the memroy card in the new PLC and powering it up  will transfer the content of the last download on the memory card to the new CPU memory: hardware and communication configuration, program blocks, system data etc...

Hope this helps,

Daniel Chartier

We had a similar issue lately.

We had a old faulty CPU with a flash card, but the new one was with a SD card slot.

We also didn't have a new empty SD card, so we had to take one from an cpu we didn't use anymore.

The problem then is that the new cpu does not recognize the configuration on the SD card.

You then have to reset the SD card with the following procedure:

https://support.industry.siemens.com/cs/us/en/view/29801950

Don't know if this is any help or not, maybe you'll need it ...