At a Glance

The memory usage function is used to view:

  • the physical distribution of the PLC memory (internal memory and memory card)

  • the space taken up in the memory by a project (data, program, configuration, system)

It can also be used to reorganize the memory where possible.

NOTE: The memory usage screen is not available in simulation mode. This screen is only available in standard mode when you have built the application.

If the application has been built and if it is in NOT BUILT state due to a program modification, the screen is accessible, but it corresponds to the application built previously. Modifications will be taken into account at the next build.

Procedure

Perform these actions to access the memory usage details of the PLC:

Step

Action

1

Activate the PLC > Memory Consumption... command, which displays the corresponding screen. The memory usage statistics of a project can only be accessed if you have generated its executable in advance.

2

If you want to reorganize the memory to optimize it, activate the Pack command.

Memory usage screen Modicon M580

The memory usage screen is shown below:

Memory usage screen Modicon M340

The memory usage screen is shown below:

Memory usage screen Premium/Quantum

The memory usage screen of a PLC with a memory card and data storage is shown below. If the PLC does not have a memory card, only the information relating to the internal memory is displayed.

Description of the parameters

The following information fields are available:

Parameter

Description

User Data

This field indicates the memory space (in words) taken up by user data (objects relating to configuration):

  • Data: located data associated with the processor (%M, %MW, %S, %SW, etc.) or the input/output modules,

  • Declared Data: unlocated data (declared in the data editor) saved after power cut.

  • Unsaved Declared Data : unlocated data (declared in the data editor) not saved after power cut (available for the Hot Standby CPU BMEP586040).

User Program

This field indicates the memory space (in words) taken up by the project program:

  • Constants: static constants associated with the processor (%KW) and the input/output modules; initial data values,

  • Executable code: executable code of the project program, EFs, EFBs and DFB types,

  • Upload information : information for uploading a project (graphic code of languages, symbols, etc.).

Other

This field indicates the memory space (in words) taken up by other data relating to the configuration and the project structure:

  • Configuration: other data relating to configuration (Page0 for a Quantum PLC, hardware configuration, software configuration),

  • System: data used by the operating system (task stack, catalogs, etc.),

  • Diagnostic: information relating to process or system diagnostics, diagnostics buffer,

  • Data Dictionary: Dictionary of symbolized variables with their characteristic (address, type....)

  • Data Storage: file and data storage (only for Premium and Quantum).

Internal Memory

This field shows the organization of the PLC's internal memory. It also indicates the memory space available (Total), the largest possible contiguous memory space (Greatest ) and the level of fragmentation (due to online modifications).

Cartridge A / Cartridge B

Only for Premium and Quantum, this field shows the organization of the memory cards. It also indicates the memory space available (Total ), the largest possible contiguous memory space ( Greatest) and the level of fragmentation (due to online modifications).

Pack

This command is used to reorganize the memory structure.

Memory re-organization

Memory re-organization is activated using the Pack command.

Memory re-organization can be performed in online or offline mode (Even if the PLC is in Run or in Stop).

NOTE: Certain blocks cannot be moved in online mode. You will attain a lower level of fragmentation by re-organizing the memory in offline mode.