ETS 1542 - Introduction to Programmable Logic Controllers ETS 1542 - Introduction to Programmable Logic Controllers 3 cr. hrs. This course introduces various programmable logic controllers (PLC) and how each interface with hydraulic, pneumatic, and electrical controls for automated applications. It includes the design and troubleshooting of ladder logic programs working with the counters, registers, decoders, digital to analog converters, analog to digital converters, and storage devices. Course Designations: (OA)