Appendix C: Definitions

action: relative direction of change in output for a change in input ("direct" for changes in same direction and "reverse" for changes in opposite direction)
automatic mode: PID controller mode to enable its set point to be locally adjusted by the operator (also known as LOCAL and AUTO mode)
A/D: analog to digital converter typically used to convert an analog input to its digital value with a resolution of 0.05% for a 12 bit converter with one sign bit
COM: Component Object Model
controller action: relative direction of change in controller output for a change in controller input ("direct" for same direction and "reverse" for opposite direction)
controller tuning: adjustment of the proportional, integral (reset), and derivative mode settings for a PID controller
control interval: time interval between successive executions for digital devices (same as scan or update time and the inverse of scan rate or frequency)
controlled variable: a controller input to be kept at a set point (often a process output such as concentration, flow, pH, pressure, temperature, or level)
cascade mode: secondary PID controller mode to enable its set point to be remotely adjusted by the output of a primary controller (also known as REMOTE and CAS mode)
compression: smallest change in value of a variable that is stored by a computer or data historian (must not exceed the repeatability of the CV or the resolution of the MV)
D/A: digital to analog converter typically used to convert a digital value to an analog output with a...

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Advanced Control Unleashed: Plant Performance Management for Optimum Benefit

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Appendix C: Definitions

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