Why do we use RAM card?

Dear All,

I have read that we can use flash card or RAM card as load memory of S7-400 CPU. If we use RAM card as load memory then we must need battery to save our program, while for FLASH card we don't require battery. Then why do we use RAM card as load memory.

Regards,

Welde.

During commissioning, a RAM Card is nice because you will change and update your program.

After commissioning is finished, using a FLASH Card will prevent data lost by power failure.

Hello

There are few reasons- behind using RAM in S7-400 CPU as below.

1-To be able to change the program in RUN Mode of CPU.

2- If the program too big for internal inbuilt CPU RAM.

For More details please follow following link.

How can I get an overview of the S7-400 memory concept

Hope above Helps

Thanks

Ravi