CPU 416 How to expand load memory RAM

Hello javier;

From your screenshot it appears that you are sending most of your program into the internal RAM of the PLC  and none to yhe Flssh EPROM card.

Have you ever seen this FAQ, describing the memory structure of a S7-400:

https://support.industry.siemens.com/cs/ca/en/view/7302549

The RAM of a S7-400 is split between internal RAM, in your case it seems to hold 250 kB, and external load memory, either a RAM or Flash EPROM card. If you have been only saving your program using a standard Download operation, you have been sending it all to the internal RAM, which is now full and the Flash EPROM is empty.

"If you have a flash memory card plugged in, transfer blocks to the external load memory with "PLC >Load user program onto memory card". However, in the case of "PLC >Load user program onto memory card", the CPU has to be set to STOP mode first before the user program can be transferred."

Use the procedure above to send your program blocks to the Flash card, where they will be supported without battery power, and the temporary Data of the running program will he handled by the internal RAM chips. You might have to do a memory reset to wipe the contents of the internal RAM, once the program has been downloaded to the Flash EPROM.

Hope this gelos,

Daniel Chartier

Hello javier;

If you are still in programming and commissioning mode, I always go back to the procedure we used: when many changes were expected, use a RAM card, with standard Dowload commands, in RUN mode. When the program is tested and you are ready to transfer the project to the client, replace the RAM cards with an EPROM card, where it will be protected without battery support, using the Dowload to Memory Card procedure, in STOP mode.

As long as you have a Flash EPROM slotted in the CPU you will have to download in STOP mode  as per the procedure described on the earlier link.

Hope this helps,

Daniel Chartier