This system constant is a unique value for this PLC type. It allows programs to be compiled only for the PLC type currently selected.
#if((SYS_CURRENT_PLC AND (SYS_FP7_CPS3RES_CPS31ES ))<>0) #then
(* only code for the PLC type FP7 CPS3RES CPS31ES is executed*)
#end_if;