7.2.10 Manually Setting the Cutback Values

Enter the PID terms calculated from the table in the section 7.2.8 before setting cutback values.

 

The above procedure sets up the parameters for optimum steady state control. If unacceptable levels of overshoot or undershoot occur during start-up, or for large step changes in PV, then manually set the cutback parameters.

 

Proceed as follows:

 

Initially set the cutback values to one proportional bandwidth.

 

If overshoot is observed following the correct settings of the PID terms increase the value of ‘cB.Lo’ by the value of the overshoot in display units. If undershoot is observed increase the value of the parameter ‘cB.Hi’ by the value of the undershoot in display units.