Further information and notes

• Further information about the data for the individual CPUs can be found in the manual "Automation System S7-400 Setup and Use", Chap. 2.2 Entry ID 22586851
• Further information about the acceleration properties/behavior (cold start, warm start, ...) can be found in the manual "Automation System S7-400 CPU Data", Chap. 4.2 Entry ID 14016796
• Notes about the different types of memory cards can be found in "Automation System S7-400 CPU Data", Chap. 1.5 Entry ID 14016796
• Notes on resetting the CPU can be found in the manual "Automation System S7-400 Setup", Chap. 6.5 Entry ID 1117849
• Notes about the behavior of the CPU after POWER OFF without a back-up battery can be found in Entry ID 1994237

Tagolover

Please note that in PCS7 you can use only RAM cards, and not EPROM

Process Control System PCS 7 Tips and Tricks

Implementation:

You only use FEPROM memory cards when the user program no longer changes or only very seldom changes and you want to store the data permanently. The stored user program remains on an FEPROM memory card even if you remove the card from one AS and slot it into another AS.

Notice

Note, however, that there are programs that change the user structure on the load memory without loading. For example, the application "Route Control" is used in breweries. This application changes the length of data blocks in the load memory.

If you use FEPROM memory cards here, then the program can no longer function.

Saravana kumar

Hi Frieds,

From the discussion I got one points is that the RAM is just to extend the internal RAM of the CPU.

That means it will be sharing the load memory with the internal RAM, atfirst the block will be filled in the internal RAM and the remaining will be filled in the RAM. Am I right.

What will be the case with Flash EPROM, where the blocks will be loaded.

I know that by using the "load the program to memory card" we can dewnload the backup to the Falsh card, in that case the program will be avilable only in the Flash card? and what will be the contents of internal RAM (load memory)?

I am sorry for asking a silly question, I really got confuced.

Yoga Shankar

to the best of my knowledge, the load memory always contains the run time execution criticala data.

Saravana kumar

Yoga Shankar

to the best of my knowledge, the load memory always contains the run time execution criticala data.

Thank you for your reply.

But as per the memory concept in S7 PLC's the runtime relevant data's will be in Work memory. The load memory is only to store the blocks and configuration.

Yoga Shankar

whenever the program needs to access a certain area (db) only then will the db be loaded into the load memory.

Actually when you donwload the program by default the program will be in load memory and while executing the logic the DB's will be copied from load memory to work memory.

Yoga Shankar

when RAM is used, additional load memory space is mapped into the RAM. this might be used in a way similar to the page file in OS. When a FLASH card (FEPROM) is used, the entire card will be used as work memory only. this is because, the download needs to be done using a prommer.

About the RAM card your idea is correct.

But about the Flash card, I am sure that the flash card cannot act as the Work memory. Flash card can act as the load memory only.

My actual doubt is that when using the flash card weather load memory is shared between the internal RAM and flash card (like RAM card) or total load memory is only taken from the Falsh card.

my bad!!!!! i must have confused my self with the two terms........ sometimes it happens