30.3.2.4 Retentive Variable Settings

If variables are set to retentive, they are stored in backup memory (SRAM) and retain their values when the unit is shut down.

These values are kept until the backup battery runs out, which causes these variables to revert to their default value as defined in GP-Pro EX. When shutting down or resetting the display unit, the latest values are copied to SRAM.

Data saved in backup memory (SRAM) is lost if the battery is drained while the power is turned off. In such case, the values specified in GP-Pro EX are used as the default values.
If a transfer occurs under one of the following conditions, all variables, including Retentive Settings variables, are reset.
- In the [Transfer Settings] dialog box's [Transfer Settings] tab, under [Initialize], [Variable Value] is selected.
- In [System Settings] - [Display Unit] - [Logic], under [Register Variable], [Address Format] is selected.
- Different projects are transferred.

Refer to the following for models that support the variable's Retentive Settings.
1.5 Supported Features
The allowable number in [Retentive] is specified in the [Retentive Area Settings] in the System Settings [Logic Program] page.
30.15.1 Logic Program Settings Guide
You can check the Retentive/Volatile settings. From the [File] menu, point to [Information] and click [Project Information]. In the dialog box, select [Memory Usage], click the [Logic] tab, and in the [Variable Capacity] area click [Details].
The timing for the backup of variables defined in the Retentive Settings differs between display unit models.
SP5000 Series (excluding Open Box), GP4000 Series (excluding GP-410*), ST6000 Series, STM6000, and STC6000 Series:
Backup occurs after Address Refresh is complete. (Depending on the timing when the display unit is turned off or reset, the display unit may not back up the latest data of variables.)
30.14.3.3 Address Refresh
Other Models
Back up occurs when data of variables is updated.