Basically, this is all the years you’ve worked at Rockwell Automation.
It is used to calculate the amount of your pension benefit and to determine age + service points and your eligibility for early retirement.
In general, you earn credited service while you are actively employed as a salaried or hourly employee at a location covered by the Plan, from your first month of employment through the month in which your termination date occurs. Each calendar month counts as one twelfth of a year of credited service. A year of credited service is 365 days of credited service.