Data saved in 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 variables are set to retentive, they are stored in backup 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. Downloading a logic program will initialize variables with their default values set up in GP-Pro EX, unless you select the Retentive Transfer check box.
Data saved in 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.
Retentive Settings allow you to specify the variable points to retentive/volatile.
29.14 Settings Guide