Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Good explanation of most aspects of PLCs

This book is a good textbook for beginners and a good review/reference for more experienced PLC users. Its explanation of the new IEC 61131-3 programming languages is helpful, since many of us in the US have never dealt with anything other than Ladder Logic. For examples that require reference to a particular PLC, the book most often refers to Allen Bradly PLC5 and Siemens Simatic S7 series.