Instrumentation is the science of automated measurement and control. Applications of this science abound in modern research, industry, and everyday living. From automobile engine control systems to home thermostats to aircraft autopilots to the manufacture of pharmaceutical drugs, automation surrounds us. This chapter explains some of the fundamental principles of automatic process control.

- Basic feedback control principles
- Diagnosing feedback control problems
- On/off control
- Proportional-only control
- Proportional-only offset
- Integral (reset) control
- Derivative (rate) control
- Summary of PID control terms

- P, I, and D responses graphed
- Responses to a single step-change
- Responses to a momentary step-and-return
- Responses to two momentary steps-and-returns
- Responses to a ramp-and-hold
- Responses to an up-and-down ramp
- Responses to a multi-slope ramp
- Responses to a multiple ramps and steps
- Responses to a sine wavelet
- Note to students regarding quantitative graphing

- Different PID equations

- Pneumatic PID controllers
- Proportional control action
- Automatic and manual modes
- Derivative control action
- Integral control action
- Fisher MultiTrol
- Foxboro model 43AP
- Foxboro model 130
- External reset (integral) feedback

- Analog electronic PID controllers
- Proportional control action
- Derivative and integral control actions
- Full-PID circuit design
- Single-loop analog controllers
- Multi-loop analog control systems

- Digital PID controllers
- Stand-alone digital controllers
- Direct digital control (DDC)
- SCADA and telemetry systems
- Distributed Control Systems (DCS)
- Fieldbus control

- Practical PID controller features
- Manual and automatic modes
- Output and setpoint tracking
- Alarm capabilities
- Output and setpoint limiting
- Security

- Digital PID algorithms

- Note to students
- Proportional-only control action
- Integral-only control action
- Proportional plus integral control action
- Proportional plus derivative control action
- Full PID control action

- Review of fundamental principles
- References