Cohen Coon Tuning Method Example

The values of t and t del can be obtained by first recording the following time instances.

Cohen coon tuning method example. Jul 12 2020 cohen coon tuning process reaction curve electrical engineering ee video edurev is made by best teachers of electrical engineering ee. The original ziegler nichols method does not require a measurement of the process time constant and therefore lends itself very well to tuning level. Put the controller in manual and wait for the process to settle out. 2 4 ziegler nichols method z n 13 2 5 cohen coon method c c 15 3 methodology 3 1 introduction 17 3 2 development of process model using simulink 19 3 3 controller tuning 22 3 3 1 ziegler nichols method z n 23 3 3 2 cohen coon method c c 25 3 5 comparison 26 3 6 conclusion 26 4 result and discussion.

Cohen coon method open loop test step 1. Introduce a step change in the manipulated variable iii. The size of this step. Knowledge of process reaction curve consider a 3 tank system as shown.

Cohen coon tuning method. Make sure the process is at an initial steady state ii. General 2nd order overdamped system example as an example let s assume we have a 2 nd order overdamped system with negligible dynamics in the final control measurement elements. The cohen coon tuning method requires a measurement of the process time constant while the way we normally model integrating processes like liquid level this measurement is not available.

Next introduce a step change in the input. Wait until the process settles at a new steady state figure 1. Under manual mode wait until the process is at steady state. Based on the output obtain an approximate first order process with a time constant t delayed by t del units from when the input step was introduced.

Step test for cohen coon tuning. Plant transfer function according to this approach 1st an approximate first order plus delay time fopdt representation of process is identified based on the process reaction curve and then the pid controller parameters are obtained using appropriate cohen coon tuning values. Perform a step test to obtain the parameters of a foptd first order plus time delay model i.