Which values are determined by auto-tuning and how long does auto-tuning take?
Depending on the selected controller type, the following parameters are determined through autotuning:
|2-state controller ON/OFF function||Pb1, dt, rt, Cy1, df|
|3-state controller||Pb1, Pb2, dt, rt, Cy1, Cy2, df|
|Proportional controller||Pb1, dt, rt, df|
As soon as autotuning is started from the “Exit“ key (hold down for 2 sec), the controller attempts to determine the time response of the process by applying step changes in the manipulating variable. Autotuning evaluates the development of the process value resulting from these changes in the manipulating variable and calculates the controller parameters. During autotuning, you will see “ tune “ flashing in the bottom display.
On termination of the autotuning procedure, “ tune “ ceases to flash.
The duration of the autotuning procedure depends on the time response of the controlled process. If the process reacts relatively quickly to the changes in manipulating variable, then autotuning may be over in a matter of seconds or minutes. With slow processes, autotuning may take half an hour or longer.