The predefined variables in GP-Pro EX are called system variables.
System variables are either logic system variables (#L system variables) or HMI system variables (#H system variables). System variables indicate the state of the display unit and affect operation. Similar to symbol variables, system variables have variable types (integer/bit) and operate in the same way as symbol variables.
You cannot add or delete system variables.
The names of system variables is the same regardless of [Variable Format] and [Address Format].
#L system variables are retentive variables. Even if you turn off the display unit, their current values are saved. #H system variables are volatile variables. You can confirm if a variable is retentive or volatile in the Properties window's [Detail Settings].
#H system variables are not synchronized with logic programs. Therefore, depending on the timing you may not be able to get the exact value you were expecting.