5 - Automatic tune

5 AUTOMATIC TUNE

Start/stop of the Fuzzy Tuning The Tuning operation can be started or stopped any time.

274.8Operatormode

press until

tune

stop Toselectstart

strt

strt Toselectstop

stop

The green led 3goes on when the Fuzzy Tuning is in progress. At the end of this operation, the calculated PID terms parameter are stored and used by the control algorithm and the controller goes back to the operator mode. The green led 3 becomes off.

This function allows the calculation of the optimal PID terms parame- ters, monitoring the response of the process to disturbances.

The controller provides 2 types of “one shot” tuning algorithm, that are selected automatically according to the process condition when the operation is started.

Step response

This type is selected when, at the start of the autotune operation, the PV is far from the Setpoint of more than 5% of the span.

This method has the big advantage of fast calculation, with a reasonable accuracy in the term calculation.

Natural frequency

This type is selected when the PV is close to the SP setpoint.

This method has the advantage of a better accuracy in the term calculation with a reasonable speed calculation.

The Fuzzy Tuning determines automatically the best method to use to calculate the PID term, according the process conditions.

Step response

 

SP

Setpoint change

End of the tuning

 

operating and setting of

 

the new calculated

 

terms.

PV variable

Start of autotune

 

 

operation

Control output

 

Natural frequency

tuning start

PV variable

End of the tuning operating and setting of the new calculated terms.

Control output

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