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 the backup memory (SRAM) is lost when the power is turned off or the battery runs out. 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.

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].