This book teaches and demonstrates the basics of Siemens S7-200 Programmable Logic Controllers (PLCs). The S7-200 uses Step 7-Micro/WIN programming software. It does this with the Siemens CPU 222 S7-200 PLC. Information is provided to help the reader get and operate a CPU 222, associated hardware, and software. Examples with ladder program diagrams and circuit diagrams are provided to demonstrate S7-200 and Step 7-Micro/WIN capabilities. A person completing the examples will be able to write useful programs for the S7-200.