At a Glance

With the Pack command it is possible to reorganize the memory so as to optimize it.

To avoid certain detected errors (Internal Memory full or Cartridge Memory full) when you do a build after online modifications, the Pack command must be carried out before the online modifications.

NOTE: When the MEM status of the Status bar becomes Red, it is recommended to make a Pack command by clicking on the Pack button in the Memory usage screen of the PLC.

The necessity of Packing the internal (or cartridge) memory is evaluated by the PLC operating system and recommended when:

  • the degree of fragmentation (due to many online modifications for instance) of the memory is becoming high,

  • and/or the size of the largest contiguous block of available memory is becoming low compared to the total size of available memory.

NOTE: for Quantum PLCs, the Pack command can be used for OS version 2.3 or later.

Elements that Require Large Amounts of Memory

Certain project elements and actions consume a large amount of memory:

  • configuration with a Cartridge memory:

    • with a large section,

    • with several actions in the same SFC section.

  • configuration with an internal memory:

    • with a large DFB instances,

  • configuration with an internal memory in a Hot StandBy project:

    • several DFB instances,

    • adding or deleting DFB instances,

    • modifying an SFC section.

Procedure

Perform the following actions to use the Pack command:

Step

Action

1

Activate the PLC > Memory Consumption: command, which displays the corresponding screen.

2

In the Internal Memory or Cartridge area check the percentage values of:

  • Memory available,

  • Fragmentation,

  • Greatest / total of Memory available.

3

Check if these values are in the ranges listed in the tables below.

4

If Yes, click on the Pack button.

5

Above the Pack button, if the warning Memory optimization is not terminated, please continue to pack appears, the Pack button must be clicked again.

6

The Pack function is finished when:

  • the Pack button is grayed,

  • the Fragmentation field is equal to 0,

  • the Greatest value is near the Total Memory available value.

How the PLC detects it’s recommended to make a Pack command for Internal Memory

The following table shows how the PLC detects it’s recommended to make a Pack command, regarding the field values in the Internal memory area:

If the Percentage of Memory available

is,

then if the Percentage of Fragmentation

is,

OR if

Greatest (1) / Total Available Memory

is:

>25%

>15%

<50%

[15% ... 25%]

>10%

<80%

<15%

>5%

<90%

(1) Greatest is the Largest free contiguous block of memory available, this information is given in the Memory usage screen.

How the PLC detects it’s recommended to make a Pack command for Cartridge Memory

The following table shows how the PLC detects it’s recommended to make a Pack command, regarding the field values in the Cartridge memory area:

If the Percentage of Memory available

is,

then if the Percentage of Fragmentation

is,

OR if

Greatest (1) / Total Available Memory

is:

>25%

>10%

<70%

[15% ... 25%]

>5%

<90%

<15%

>3%

<95%

(1) Greatest is the Largest free contiguous block of memory available, this information is given in the Memory usage screen.