This document provides an introduction to instruments used in process control industries. It describes the main components of an instrumentation system, including sensors, transducers, converters, transmitters, indicators, recorders, controllers, final control elements, and actuators. Sensors measure process parameters and transducers convert these measurements to electrical signals. Transmitters then standardize these signals so they can be processed by other equipment for indication, alarms, or automatic control. Common controller types are PLCs and DCSs. Final control elements and actuators are used to physically affect the process. The next session will cover sensors and transmitters in more detail.