[?]: S7313c can't work without MMC

[Eng_Ali]

Hello ;

When trying to download a simple project with blanck OB1 (just for test ) the message appears
[download 13:4589] and the detail is the block/op.sys update is too large.. can not load SDB4.

even when delet all system data download not succeed

this time the message is [294:38]
possible load memory botleneck our not enough memory in memory card..

I use s7 313-5BF03-0AB0..without MMC and Step7 V5.4 SP4 with hardware updated

any help

regards..

[kriztof]

I use s7 313-5BF03-0AB0..without MMC and Step7 V5.4 SP4 with hardware updated

You can't use your PLC without MMC card.
Step7 loads your program to MMC card and then PLC loads its contents to RAM.

[Eng_Ali]

thanks for reply..
sorry for question ...i am new with siemens

[Pokajy]

You can't use your PLC without MMC card

You could use it without mmc , if it was S7-400 cpu.

[Trafo]

I use s7 313-5BF03-0AB0..without MMC and Step7 V5.4 SP4 with hardware updated

You can't use your PLC without MMC card.
Step7 loads your program to MMC card and then PLC loads its contents to RAM.

You can't use your PLC without MMC card. YES
Step7 loads your program to MMC card and then PLC loads its contents to RAM.

[kriztof]

You can't use your PLC without MMC card. YES

MMC contains hardware configuration and user program. PLC loads config and blocks from MMC after power up. Notice, new PLC modules are not equipped with battery so how do you think they store program or configuration? Have you ever tried to load your program to PLC without MMC card or just tried to run?

[Trafo]

Hi, I like to discuss about memory areas in S7-300. I think that SIEMENS never tried to publish clear picture of memory organisation in CPU.
"You can't use your PLC without MMC card." YES, THAT is TRUE.
Basically there two Siemens terms. Work memory (RAM executable user program) and Load memory (entire user program) :
Load memory can be integrated in CPU or on MMC
Because of that we can not say for shore in which part of load memory our program is. We only know without MMC "there is no dance".

Writing on MMC and reading from it is slow operation. In case of power-off there is no time for this operation. I personally think that program is in NV-RAM.

Clearly we can transfer program to MMC on demand.
Program is transferd from(if there is on) MMC during cold restart is performed.
So if you have more information about memory organisation let me now.

[CoMod]

So if you have more information about memory organisation let me now.

http://databridge.narod.ru/Hardware_S7_300/S7_300.htm

[kriztof]

Writing on MMC and reading from it is slow operation.

Typical MMC card like Kingmax 32MB in sequential read mode transfers 3126 KB/s and in sequential write mode transfers 1368KB/s, S7-314 has only 96KB integrated work memory. How long it takes to load program from card to work memory?

[Trafo]

I read pdf: http://support.automation.siemens.com/W ... aller=view
and I must write that you were right.
By Siemens:

The entire user program is downloaded by means of the PG/PC to the CPU via the SIMATIC Micro Memory Card.
The three memory areas of your CPU:
Load memory
The load memory is located on the SIMATIC Micro Memory Card. The size of the load memory corresponds exactly to the size of the SIMATIC Micro Memory Card.
It is used to store code blocks, data blocks, and system data (configuration, connections, module parameters, etc.).
Blocks that are identified as not relevant for execution are stored exclusively in the load memory.
You can also store all the configuration data for your project on the SIMATIC Micro Memory Card.
Note
You must insert a SIMATIC Micro Memory Card into the CPU to enable loading of user programs and operation of the CPU.

System memory

The system memory is integrated in the CPU and cannot be expanded.
It contains
● the address areas for bit memories, timers, and counters
● the process images of the inputs and outputs
● local data

Main memory

The work memory is integrated in the CPU and cannot be extended. It is used to execute the
code and process user program data. Programs only run in the main memory and system
memory.
5.1.2 Retentivity of load memory, system memory, and main memory
Your CPU is equipped with a maintenance-free retentive memory, i.e. no back-up battery is required for its operation.
Due to the retentivity, the content of the retentive memory is retained even during a POWER OFF and restart (warm restart).

Retentive data in the load memory

Your program in the load memory is always retentive: It is stored on the SIMATIC Micro Memory Card, where it is protected against power failures or memory resets

Retentive data in the system memory

In your configuration (Properties of CPU, Retentivity tab), specify which part of memory bits, timers and counters should be kept retentive and which of them are to be initialized with "0" on restart (warm restart).
The diagnostic buffer, MPI address (and baud rate), and runtime meter data are generally stored in the retentive memory area on the CPU.
Retentivity of the MPI address and baud rate ensures that your CPU can continue to communicate, even after a power loss, memory reset, or loss of communication parameters (e.g. due to removal of the SIMATIC Micro Memory Card or deletion of communication parameters).

Retentive data in the main memory

The contents of retentive DBs are always retentive at restart and POWER ON/OFF.
Retentive data blocks can be uploaded to the main memory in accordance with the maximum limit allowed by the main memory.
In the case of CPU versions V2.0.12 and higher, non-retentive DBs are also supported.
Non-retentive DBs are initialized from the load memory with their initial values at restart or POWER ON/OFF. Non-retentive data blocks and code blocks can be loaded in accordance with the maximum main memory limit.
The size of the retentive main memory (for retentive data blocks) of the CPU can be found in the chapters "Technical specifications of CPU 31x (Page 239)" and "Technical specifications of CPU 31xC (Page 183)".

I'm apologize for