Содержание
- 2. An automatic control system adds two elements to the three basic components of automatic control. A
- 3. An automative cruise control is an example of automatic control The automobile is accelerated to a
- 4. Self regulation Some automatic processes are self regulating. For example, a tank of liquid that discharges
- 5. An example of process that is not self-regulating is chemical reaction.
- 7. Process dynamics The degree of difficulty of controlling a process depends on the characteristics of the
- 9. Process Gain Gain is a ratio of the change in output to the charge in input
- 10. Lags A lag is a delay in the response of a process that represents the time
- 12. Dead time Dead time is the period of time that occurs between the time change is
- 13. Control functions Controllers are made up of various functions, such as adjustable setpoints, setpoint tracking, manual
- 16. Control actions Direct action is a form of control action where the controller output increases with
- 21. Bumpless transfer Bumpless transfer is a controller function that eliminates any sudden change in putput value
- 23. Controller Algorithms The actions of controllers can be divided into groups based upon the functions of
- 24. A common example of a discrete controller is a home hot water heater. When the temperature
- 26. MULTISTEP CONTROLLERS Multistep controllers are controllers that have at least one other possible position in addition
- 27. CONTINUOUS CONTROLLERS Controllers automatically compare the value of the PV to the SP to determine if
- 29. Why Controllers Need Tuning? Controllers are tuned in an effort to match the characteristics of the
- 30. Examples: Change in Input to Controller - 10% Change in Controller Output - 5% Gain =
- 31. PROPORTIONAL ACTION Proportional (P) control is method of changing the output of a controller by an
- 33. PROPORTIONAL BAND Proportional Band (PB) is another way of representing the same information and answers this
- 38. Proportional, Derivative Control The stability and overshoot problems that arise when a proportional controller is used
- 39. INTEGRAL (I) CONTROL (RESET) Duration of Error and Integral Mode - Another component of error is
- 42. DERIVATIVE CONTROL Derivative Mode Basics - Some large and/or slow process do not respond well to
- 43. Derivative Mode Example - Let's start a closed loop example by looking at a temperature control
- 45. Proportional+Integral+Derivative Control Although PD control deals neatly with the overshoot and ringing problems associated with proportional
- 46. The Characteristics of P, I, and D controllers A proportional controller (Kp) will have the effect
- 47. Proportional Control By only employing proportional control, a steady state error occurs. Proportional and Integral Control
- 48. The Characteristics of P, I, and D controllers
- 49. Tips for Designing a PID Controller 1. Obtain an open-loop response and determine what needs to
- 50. Not every process requires a full PID control strategy. If a small offset has no impact
- 51. By using all three control algorithms together, process operators can: Achieve rapid response to major disturbances
- 52. Cascade (Remote Setpoint controllers) Cascade control is a control strategy where a primary controller, which controls
- 53. Ratio control Ratio control loops are designed to ratio (or proportion) the rates of flow between
- 54. Feedforward control Feedforward control is a control strategy that only controls the inputs to a process
- 55. Digital controllers A digital controller is a controller that uses microprocessor technology and special programming to
- 57. Direct Computer Control System A direct computer control system is a control system that uses a
- 58. Distributed Control Systems (DCS) A distributed control systems is a control system where the individual functions
- 60. Programmable Logic Controller (PLC) A programmable logic controller is a control system with an architecture very
- 61. Automatic control system In the control method of the automated control systems (ACS) are divided into
- 62. Adaptive ACS Adaptive ACS - these are systems in which the parameters of the control devices
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