Honeywell 9782 Series manual Adjust effective proportional band width, Unacceptable overshoot

Proportional Control Tuning

Appendix A

Proportional Control Tuning

Adjust effective proportional band width

The only adjustment in proportional-only control is the effective proportional band width. For startup, enter the desired control setpoints for discrete control types (or the value representing 0% in CAT control). Set the proportional band limits (value for 100% output) to the extreme process values anticipated before treatment of the batch.

Treatment takes too long, but no unacceptable overshoot

After observing treatment performance, some improvement may be possible. If treatment takes too long, and there has been no unacceptable overshoot beyond the setpoint, make one or more the following changes:

∙Increase the reagent delivery capacity.

∙Increase the reagent concentration.

∙Decrease the proportional band width by adjusting the proportional band limit closer to the setpoint.

Unacceptable overshoot

If unacceptable overshoot occurs, make one or more of the following changes:

∙Increase mixing in the treatment tank.

∙Reduce the reagent delivery capacity.

∙Reduce the reagent concentration.

∙Widen the proportional band by adjusting the proportional band limit further from the setpoint.

7/99 9782 Series Conductivity/Resistivity Analyzer/Controller - Operator’s Manual Appendix A - 1