Comprehensive Guide to Learning PLCs
These are the most common sequencing methods used in PLC programming.
Take your time and go through each one, you will run into all of them out in the field. There may be ones you prefer but there is no "best" method.
One key advantage to the PLC programming methods in this series is they work with all Allen Bradley PLCs including the Controllogix and Compactlogix with Studio 5000, formerly RsLogix 5000, RsLogix 500 for the SLC 500 and Micrologix PLC, and Connected Components Workbench for the Micro800 PLC. In fact these methods work with most all major PLC manufacturers.