In this chapter, we explored the genesis of Ladder Logic programming and the IEC programming language standards. We learned how to create Ladder Logic by dragging and dropping elements to a ladder rung in a routine. We also learned the importance of buffering inputs and outputs and some techniques for accomplishing this. We now understand how to read and write most Ladder Logic programs, and as it is based on the IEC standard, this knowledge can be applied to PLC programs from a myriad of vendors. At this point, it would not be too difficult for you to also write Ladder Logic for other vendors' PLCs.
In the next chapter, we will introduce another IEC language, FBD, and explore its use within the Logix family.
