Memory limitations for program code?

Hi!

I have 6ES7315-2EH14-0AB0 and it says in properties of CPU: 384 KB work memory;

My program has totaly size in working memory 212962byte.

Module information of CPU says that I still have 180kb free working memory but I can't add aditional logic because i receive error:

Exist some limitation how much working memory is dedicated to code and how much to code?

BR Janez

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Split from cpu 315.

janbar_k

Hi!

I have 6ES7315-2EH14-0AB0 and it says in properties of CPU: 384 KB work memory;

My program has totaly size in working memory 212962byte.

Module information of CPU says that I still have 180kb free working memory but I can't add aditional logic because i receive error:

E: 0xFFDF_0117: [S7DOS] The block/op. sys. update is too large.

Exist some limitation how much working memory is dedicated to code and how much to code?

BR Janez

Hello,

please have a look:

 https://support.industry.siemens.com/cs/document/7302326/how-can-you-obtain-an-overview-of-the-memory-concept-of-simatic-s7-300-cpus-and-c7-devices-?dti=0&lc=en-WW

 What would you do a System Update?

I check documentation but I didn't notice any division between code and data.

Only is mentioned that max 128kb is reserved for retentive DB.

If this division is fixed then i should have 256kb for code.

hi janbar_k,

what kind of block do you want to load?

Can you show us a screenshot of the error-message?

What kind of error is on the CPU? Please export the diagnosic buffer of the CPU and share it with us.

regards,

It doesen't came to erro on CPU, because mentioned error is durring download to CPU.

In my opininon is error is related limitation of working memory on CPU  and requirement of program (offline).

Strange is that Module information shows 54%of occupied memory, but Simatic Manager doesn't allow to download more bigger program. 

janbar_k

It doesen't came to erro on CPU, because mentioned error is durring download to CPU.

In my opininon is error is related limitation of working memory on CPU  and requirement of program (offline).

Strange is that Module information shows 54%of occupied memory, but Simatic Manager doesn't allow to download more bigger program. 

 have a look on the picture you shared with us.

there is definitly an error on the CPU. See attachment

Do you want us to help you, or not?

What kind of block do you want to load?

regards,

Hello,

I just have one question. Are you trying to download entire program or just a block? You should try to download single block only. If you are downloading entire logic again then I think it should work only if that much load memory is free, which is not in your case.

If you're downloading single block then, Is it new block or existing block is changed and downloaded? Try doing minor change in a block and try to download to see what happens.

Finally, You can always delete unnecessary blocks online to free some memory. But make sure it is not really called anywhere. Deleting used block will stop CPU.

Hope this helps.

Hi!

First was made CPU/ PLC/ Clear/Reset to clear memory of CPU.

Picture was taken when complete download was succesful (size of program is as writen in picture).

When program code is bigger (few kb) complete download  operation fail with before menitioned error.

CPU is in error because missing some DP slaves.

I attached details of code which can be loaded in CPU.

Most of code is written in CFC, custom block programmed in SCL.

BR JP

Hello janbar_k

Your block numbers are within limits. Make sure that they are not numbered beyond limit for ex. FC 10000. Single block should not violate maximum size limits mentioned in data sheet.

I don't understand why you need to download entire program again once you have all the blocks downloaded. You just need to download block that you change or add. As I have mentioned in above post all the download content goes to load memory and then copied to work memory. So for downloading all the blocks again you need that much load memory empty. Please find attachment on below link, it explains memory concept clearly

https://support.industry.siemens.com/cs/document/7302326/how-can-you-obtain-an-overview-of-the-memory-concept-of-simatic-s7-300-cpus-and-c7-devices-?dti=0&lc=en-WW

CPU load memory consist of internal ram and external feprom(MMC). Download loads all the blocks to load memory ram as well as feprom. You have option of load to memory card in step7 but it will erase all the blocks in MMC and load it only in MMC so I am not sure of its effect and have not tried this ever. If you can stop PLC then you can try this in stop mode but ensure you have backup.

Hope this helps.