Can increase siemens work memory???

MOeZ

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Join Date
Nov 2009
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singapore
Posts
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Hello all,

When i download new programs to S7-400 old type CPU with 8MB flash card attach, error is coming " memory bottle neck problem " and CPU give me error eventhough i reset all memory.

When i check work memory code is 99%. can i increase workmemory in others way or ...? kindly please advise.

Bgrds,
 
You can not increase the work memory size, only the load memory size. You have to check what is the work memory of your CPU (it isn't 8MB, the flash module is load memory) and eventually change CPU with one with more work memory. This info is clearly indicated in the catalogs which you can find on the Siemens support site.

Kind regards,
 
What you need to do now is look closely at your program.
Elliminate any blocks including Library functions that are not being used.
If you are not using STL then look to start converting some LAD to STL.
Look at the efficiency of your programming. Perhaps you have some often repeated code that could be a subroutine.
 
Right click on the blocks folder to display the Object properties then click on the blocks tab. You will see how much memory is required.

wm.JPG
 
Many thanks for yours prompt reply!

Hello to all,

Many thanks for your prompt reply. It's really helpful in current situration (south china sea). after change lad to stl some codes it's reduce to 83%.

let me confirm please, workmemory is i cann't increase even i have bigger size flash card and it's depend on CPU model, isn't it?

the only i can increase is Change CPU, right?

many thanks, again.

Capture1.PNG
 
Hello to all,

Many thanks for your prompt reply. It's really helpful in current situration (south china sea). after change lad to stl some codes it's reduce to 83%.

let me confirm please, workmemory is i cann't increase even i have bigger size flash card and it's depend on CPU model, isn't it?

the only i can increase is Change CPU, right?

many thanks, again.

Hello david;
Confirming Jean-Pierre's earlier answer, the work memory in S7 PLCs is a parameter of the type of CPU, and cannot be changed. The load memory of a S7-400 PLC can be extended through the use of a bigger RAM or FEPROM card; the same is true for a S7-300 PLC, but you must use a MMC card.
The attached picture is extractyed from a 2004 S7-400 technical manual I had on my old harddrive, so it should be from around the time of your own processor.
Hope this helps,
Daniel Chartier

S7-400 memory.jpg
 
Last edited:
Hello david;
Confirming Jean-Pierre's earlier answer, the work memory in S7 PLCs is a parameter of the type of CPU, and cannot be changed. The load memory of a S7-400 PLC can be extended through the use of a bigger RAM or FEPROM card; the same is true for a S7-300 PLC, but you must use a MMC card.
The attached picture is extractyed from a 2004 S7-400 technical manual I had on my old harddrive, so it should be from around the time of your own processor.
Hope this helps,
Daniel Chartier

Hello,

Many Thanks again to all. really helpful info.
 
helo,
my load memory is not enough for 414 cpu, should i purchase ram type or feprom type for expand my load memory?
 
How can I get an overview of the S7-400 memory concept?Hide part numberDisplay part numberPart number:
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Description:
This entry describes the memory concept for SIMATIC S7-400 CPUs and for SIMATIC S7-318 CPUs. This is illustrated once again by a diagram at the bottom of the entry.
The memory in SIMATIC S7-400/S7-318 CPUs can be written to via the following 3 areas: load memory, main memory and system memory.
  • Load memory:
    The load memory can be divided into the external and the internal load memories. The internal load memory is a RAM memory which is integrated into the CPU. Blocks can be transferred from the programming device (PG) to the load memory in the CPU with "PLC/Load". The main memory is updated here at the same time, whereby the runtime-relevant code and data blocks are transferred to the main memory.
    The load memory can be extended via a RAM memory card or a flash memory card. The memory card then acts as the external load memory.

    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.
    If you have a RAM memory card inserted, the program can be transferred to the CPU via "PLC > Load". The main memory is also updated here at the same time, whereby the runtime-relevant code and data blocks are transferred to the main memory. The internal RAM load memory is filled first. The other blocks are only written to the RAM memory card when it is full.
All the program blocks and data blocks can be loaded into the load memory via the programming device (PG).
  • Expanding the load memory with a memory card: The following points determine the decision on which memory card to use:
    • Do you wish to retain the user program on the memory card when the power is OFF and without a back-up battery? If so, this would necessitate the use of a flash memory card.
      Warning:
      If you use a flash memory card without back-up batteries, the blocks in the RAM part of the load memory and the data (main memory and system memory) will be lost when the power is OFF.​
    • Do you wish to be able to change the user program in RUN mode, and is the program too big for the internal RAM? If so, this would necessitate the use of a RAM memory card. When using a RAM memory card, the system must be battery-operated so as to back up the RAM memory card data and the data in the internal RAM if there is a power failure.​
  • If you have a memory card inserted, the operating system asks for a overall reset (STOP LED flashes slowly at 0.5 Hz). You can initiate the reset procedure as follows: Move the switch to MRES position and then back to STOP again. The STOP LED then flashes for at least 3 seconds at a rate of 2 Hz (overall reset is performed) and, after that, lights up permanently. If you have a flash memory card inserted, following the overall reset the CPU copies the user program and the saved system parameters from the flash memory card to the main memory.

    Important:
    The memory card must remain inserted while the program is being processed. If you insert or remove the memory card while the power is ON, the CPU asks for an overall reset whereby the STOP LED flashes slowly at 0.5 Hz. If you insert or remove the memory card while the power is OFF, the CPU performs an overall reset automatically after being switched back on.

  • Main memory:
    The main memory is divided into two parts. One of the parts is used for the runtime-relevant code. The process input image (PII), the process output image (POI) and the diagnostics buffer are also saved in the main memory for the code. The other part of the main memory is used for the runtime-relevant data and also contains the data from the local data stack. The main memory is a battery-backed RAM.
    If you change the division of the main memory by means of parameter assignment in "HW Config > Object properties > ...", the main memory is reorganized when the system data is loaded into the CPU. As a result, data blocks which have been generated by SFC are deleted, and the other data blocks are preset with initial values from the load memory. The portion of the main memory which can be used for code or data blocks is changed when the system data is loaded whenever you change the following parameters:
    - Size of the process image (in bytes; in the "Cycle/Clock marker" tab)
    - Communication resources (in the "Memory" tab)
    - Size of the diagnostics buffer (in the "Diagnostics/Clock" tab)
    - Quantity of local data for all priority classes ("Memory" tab)

    If you change the system data, you need to allow for the following storage requirements during parameter assignment:
 

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