Role of PID in Process Step Testing

This article discusses the role of PID controllers in process step testing in chemical engineering applications. It explains the Proportional Integral Derivative (PID) terms and their functions, including the proportional (P), integral (I), and derivative (D) terms. The article also highlights the importance of loop tuning and the use of PID controllers in the chemical process industries.

Running head: ROLE OF PID IN PROCESS STEP TESTING
Role of PID in process step testing
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Author Note

1ROLE OF PID IN PROCESS STEP TESTING
Process step testing is a multiple step process of tuning the Proportional Integral
Derivative or the PID controllers with the involvement of the open loops and the closed loops.
The tuning process of the PID controllers are used in various purposes such that in the process of
Chemical Engineering applications1,2. The process step testing is the combination of the control
engineering and the chemical engineering. The fundamental building block of the control system
of the control industry is the control loop that is beneficial in controlling just one single process
variable. PID controllers are widely use in the chemical process industries for process step
testing due to their simple nature.
Proportional (P) – The proportional (P) term of the PID controller in loop tuning sets the output
of the controller in accordance with the difference in the value of the process variable and the
setpoint3,4. The loop response is directly proportional to the proportional gain of the controller.
Integral (I) – The Integral (I) term of the PID controller is used for the summation of the setpoint
error with respect to time and the output of the controller is adjusted until the setpoint error
becomes zero1,3. The objective of the Integral term is to remove the setpoint error completely but
excessive integral action may lead to the oscillation of the loop.
Derivative (D) – The derivative (D) term of the PID controller is used for reducing the controller
output when the rate of change in the process variable rapidly changes or the vice versa takes
place3. It is useful in providing stability to the controller. However, it is sensitive towards noise
and should be used cautiously.

2ROLE OF PID IN PROCESS STEP TESTING
Figure 1: Maintenance of the conditions at setpoint based on the changing information about the
process variable by the controller.
(Source: Internet)

3ROLE OF PID IN PROCESS STEP TESTING
References
1. Shahrokhi M, Zomorrodi A. Comparison of PID controller tuning methods. Department of
Chemical & Petroleum Engineering Sharif University of Technology. 2013, pp.1-2.
2. Alagoz BB, Ates A, Yeroglu C. Auto-tuning of PID controller according to fractional-order
reference model approximation for DC rotor control. Mechatronics. 2013, 23(7):789-97.
3. Shamsuzzoha M. Closed-loop PI/PID controller tuning for stable and integrating process with
time delay. Industrial & Engineering Chemistry Research. 2013, 52(36):12973-92.
4. Chopra V, Singla SK, Dewan L. Comparative analysis of tuning a PID controller using
intelligent methods. ACTA Polytechnica hungarica. 2014, 11(8):235-49.