Process Control: Modeling, Design, and Simulation

4.2. First-Order + Dead Time

Recall that a first-order + dead-time process, represented by the transfer function relationship

Equation 4.1

has the following output response to a step input change,

Equation 4.2

where the measured output is in deviation variable form. The three process parameters can be estimated by performing a single step test on the process input.

The gain is found as simply the long-term change in process output divided by the change in process input. Also the time delay is the amount of time, after the input change, before a ...