Copyright Goodheart-Willcox Co., Inc. Chapter 6 PLC Programming 91 Introduction A relay logic diagram shows the logical relationships between devices. A ladder logic diagram is the program that is actually loaded into the programmable logic controller. In this chapter, you will learn the correct method of drawing ladder logic diagrams, including the routine for converting the relay logic diagrams to PLC ladder diagrams. You will study how to program the Allen-Bradley Small Logic Controller (SLC 500) series programmable logic controllers using the Rockwell RSLogix 500 software. You will also learn how to troubleshoot a PLC system using force instruction, create reports, and use the PLC utility software commands. Several examples throughout the chapter illustrate all the steps required to implement these objectives. Learning Objectives After completing this chapter, you will be able to: • List the rules for creating a PLC ladder logic diagram. • Convert a relay logic diagram to a PLC ladder logic diagram. • Create ladder logic diagrams when the PLC is in the offline mode. • Download PLC ladder logic diagrams and test them. • Use the force instruction for troubleshooting.g • Create and print program reports. • Save and open ladder diagram project files.