DUAL-VALVE PRESSURE CONTROLLER operating manual
23
Tuning the PD²I control algorithm
The controller’s PD²I control algorithm (also called PDDI) is used to
provide faster response, most commonly in dual-valve flow and pressure
controllers.
•
The larger the
P
gain, the more aggressively the
controller will correct errors between the commanded
setpoint and the measured process value.
•
The larger the
I
gain, the faster the controller will
correct for offsets based on the size of the errors
and the amount of time they have occurred.
•
The larger the
D
gain, the faster the controller will predict
needed future corrections based on the current rate of
change in the system. This often results in slowing the
system down to minimize overshoot and oscillations.
Troubleshooting valve performance with PD²I tuning
The following issues can often be resolved by adjusting the PID gain
values for your pressure controller.
Fast oscillation around the setpoint
•
Increase the P gain in increments of 10%, and
then adjust the I gain to fine-tune.
Overshot setpoint
•
If D is not zero, increase the P gain in increments of 10%.
•
In rare situations D may be zero; in that case, decrease
the P gain in 10% increments to avoid overshoot.
Delayed or unattained setpoint
•
Increase the P gain in increments of 10%, and
then increase the I gain to fine-tune.
✓
Valve tuning can be complex. If you have any trouble, please
call support (
) to guide you through the process.
Or, visit
for more detailed instructions.
