P I D Control
PID Controls: Practical Aspects
Defining related parameters of PID control in an industrial context
Describing and explaining integrator windup and ways to reduce it
Describing one technique of bumpless auto-manual transfer
Describing digital implementations of PID control
Today, we will focus on practical aspects of PID control. Let's start with the PID equation:
PID equation: u(t) = Kp*e(t) + Ki*integral(e(t)) + Kd*(de(t)/dt)
Kp is the proportional gain and Ki and Kd are the integral and derivative gains,
respectively. Let's define some terms:
Proportional Gain and Proportional Band
Proportional gain is the change in controller output per unit change in error:
Kp = delta u / delta e or u / e
Proportional band is the band of error that causes a 100% variation in the controller output,
expressed as a percentage of the measurement range:
Proportional band = 100% / K
For example, if a temperature control loop has a full scale measurement of 50 degrees
Celsius and an error of 2 degrees Celsius causes a 100% change in input, then the
proportional band is 4%.
Integral Gain and Integral Time
Integral gain is the product of the proportional gain and integral time:
Ki = Kp * Ti
Integral time is the time taken to repeat the proportional control effort or action for a step
error signal.
Derivative Gain and Derivative Time
Derivative gain is the product of the proportional gain and derivative time:
Kd = Kp * Td
PID Controls: Practical Aspects
Defining related parameters of PID control in an industrial context
Describing and explaining integrator windup and ways to reduce it
Describing one technique of bumpless auto-manual transfer
Describing digital implementations of PID control
Today, we will focus on practical aspects of PID control. Let's start with the PID equation:
PID equation: u(t) = Kp*e(t) + Ki*integral(e(t)) + Kd*(de(t)/dt)
Kp is the proportional gain and Ki and Kd are the integral and derivative gains,
respectively. Let's define some terms:
Proportional Gain and Proportional Band
Proportional gain is the change in controller output per unit change in error:
Kp = delta u / delta e or u / e
Proportional band is the band of error that causes a 100% variation in the controller output,
expressed as a percentage of the measurement range:
Proportional band = 100% / K
For example, if a temperature control loop has a full scale measurement of 50 degrees
Celsius and an error of 2 degrees Celsius causes a 100% change in input, then the
proportional band is 4%.
Integral Gain and Integral Time
Integral gain is the product of the proportional gain and integral time:
Ki = Kp * Ti
Integral time is the time taken to repeat the proportional control effort or action for a step
error signal.
Derivative Gain and Derivative Time
Derivative gain is the product of the proportional gain and derivative time:
Kd = Kp * Td
