This book teaches and demonstrates the basics of the Siemens S7-1200 family of programmable logic controllers. Information is provided to help the reader get and operate an inexpensive CPU 1212C programmable logic controller, associated hardware, and STEP 7 Basic software. Examples with circuit diagrams are provided to demonstrate CPU 1212C ladder logic program capabilities. Information is also provided to relate the CPU 1212C to other programmable logic controllers. The person completing the examples will be able to write useful ladder logic programs for the entire S7-1200 family of programmable logic controllers.