what is PID in bioreactor how to calculate
PID (Proportional-Integral-Derivative) control is a control loop feedback mechanism used to regulate the temperature, pH, and other process variables in a bioreactor. It is commonly used in the control systems of bioreactors to maintain a steady state and avoid large fluctuations in the process variables.
The PID controller
calculates the error between the desired set point and the current process
variable and then generates a correction signal to adjust the process. The
correction signal is generated by combining three control terms:
Proportional control: This
term generates a correction signal that is proportional to the error between
the set point and the current process variable. The proportionality constant is
known as the proportional gain (Kp).
Integral control: This term
generates a correction signal that is proportional to the integral of the error
over time. The integral gain (Ki) is used to adjust this term.
Derivative control: This
term generates a correction signal that is proportional to the derivative of
the error over time. The derivative gain (Kd) is used to adjust this term.
The PID controller uses
these three control terms to calculate the overall correction signal. The
correction signal is then used to adjust the process by changing the flow rate
of the coolant, the agitation rate, or other process variables.
To calculate the PID gains,
there are several methods such as Ziegler-Nichols, Cohen-Coon, Tyreus-Luyben,
and so on. These methods can be used to determine the optimal values of the
proportional, integral, and derivative gains for a specific process. Once the
PID gains are calculated, the controller can be tuned to achieve the desired
performance.
It is worth noting that the
choice of the optimal values of PID gains depends on the process and the
desired performance, so it's important to use a systematic approach when tuning
the controller to achieve the best results.
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