Configuration for Personal pay allowance

Client requirement: Basic salary for employees is based on slabs and annual increment is processed every year 3%. If the increment crosses the basic salary maximum slab the balance amount to be reflected in personal pay allowance. i need support in the configuration of personal pay allowance

eg: e3-30,000 to 50,000

current basic salary for an employee is 50,000 and increment is processed, the increment amount to be reflected in personal pay allowance.