Siemens Industry Online Support
Siemens AG
Entry type: FAQ Entry ID: 97553417, Entry date: 03/23/2016

How do you estimate the memory requirements of your project in the load memory of a SIMATIC S7-1500?

  • Entry
  • Associated product(s)
Contrary to SIMATIC S7-300/S7-400, ET 200S and WinAC RTX, with the Advanced Controller SIMATIC S7-1500 and Distributed Controller SIMATIC ET 200 SP the information about data types, program code, symbols and comments is stored in the load memory.

The following S7 program information is stored in the load memory of the Advanced Controller SIMATIC S7-1500 and Distributed Controller SIMATIC ET 200 SP (Open Controller):

  • Code blocks (FCs, FBs and OBs)
  • Data blocks (DBs)
  • Technology Objects

  • Data types
  • PLC tags
  • Information about program code, symbols and comments

This means that with the SIMATIC S7-1500 a program is typically larger by a factor of 10 than with an S7-300/S7-400 CPU, ET 200S CPU and WinAC RTX.

The load memory of an S7-1500 CPU is on the SIMATIC Memory Card. Proceed as follows to determine the memory requirements of your user program and thus the size of the memory card required.
In the project you mark the CPU for which the memory requirements are to be determined. In the menu you click "Tools" and then "Memory load". See Figs. 1 and 2.

Fig. 1

Fig. 2
Note that the data listed below is also on the SIMATIC Memory Card in addition to the user program and that this data cannot be determined with "Memory load".
  • Hardware configuration
  • Connection configuration
  • Recipes, data logs and HMI backups
  • Non-SIMATIC files like PDF, etc.

Estimation of the load memory on an SMC
In STEP 7 (TIA Portal) V13+SP1 and higher you can use a folder as user-defined card reader in order to estimate the load memory requirement of your S7-1500 CPU. You do not need an SMC for this. The size of the destination folder gives you information about the real memory requirement.

  1. Create a folder in the Windows Explorer, on drive D:, for example. Name the folder "01_SMC_Memory".
    The real memory requirement depends also on the type of SMC and from the hard disk or size of the sectors.
  2. In the project navigation of STEP 7 (TIA Portal) you open the folder "Card Reader/USB Memory".
  3. Double-click the function "Add User-defined Card Reader".
  4. In the "Search folder" dialog that opens you select your storage path as in this example on drive D: "01_SMC_Memory" and click OK. The Card Reader folder is then created by STEP 7 (TIA Portal).
  5. Now, as shown in Fig. 3, drag-and-drop the complete S7-1500 CPU station to the path "(D:\01_SMC_Memory)" in the Card Reader folder.

    Fig. 3
  6. Then the "Load preview" dialog opens. Click the "Download" button to transfer the program from the S7-1500 CPU to the Card Reader folder.
  7. Switch to the Windows Explorer and navigate to the your created storage path, D:\01_SMC_Memory, for example. The "SIMATIC.S7S" folder contains the STEP 7 (TIA Portal) program.
  8. Right-click "SIMATIC.S7S" and select "Properties" in the pop-up menu.

    Fig. 4

  9. In the "SIMATIC.S7S Properties" dialog you go to the "General" tab and can read off the required size on the disk.

When configuring the SIMATIC Memory Card you must also provide for enough free memory for the download procedures. More information about this is available in Entry ID: 107108015.

When the plant is in operation the SIMATIC memory card can be written with data logs, for example. Make sure that you delete the data logs again in good time to avoid the memory becoming full too quickly.

Now you can better estimate the required size of the load memory before purchasing the SMC and thus avoid bottlenecks during commissioning.

Creation Environment
The screens in this FAQ response were created with STEP 7 (TIA Portal) V13.

Security information
In order to protect technical infrastructures, systems, machines and networks against cyber threats, it is necessary to implement – and continuously maintain – a holistic, state-of-the-art IT security concept. Siemens’ products and solutions constitute one element of such a concept. For more information about cyber security, please visit