Process Controllers Process controllers use one or several of the following control modes 1. On-off 2. Proportional 3. Integral (also called reset) 4. Derivative (also called rate) Most digital controllers have all of the above control modes included. They are also usually provided with anti-reset windup. Analog and pneumatic controllers often do not include all three control modes or anti-reset windup.
Control modes In general, use the following control modes for the indicated control loop. • Flow -- Use proportional plus integral. • Level -- Use proportional plus integral. • Pressure and Temperature -- Use proportional plus integral. Note - Use proportional plus integral plus rate when the application requires a quick response time