PID tool kit

[Swimmer]

Controlling the RPM of a motor. Using the linear fit coefficients.vi to get the output RPM of the motor to achieve the appropriate RPM for the fixture. The input to the vi are 2 arrays. The first is the RPM Array that has 2 rows, 0,current measured RPM
The 2nd is the 0,current command.
The result from this vi is the slope. I divide the new RPM setpoint by the slope to get the new command.
Since the motors are fairly linear this gets me with in +-20 RPM. Then I go into a while loop where I make fine adjustments to the RPM until the setpoint is reached.

Question: Is there some thing in the PID tool kit that will do all of this more neatly and quickly and accurately?

My current process of adjustment takes about 4 seconds to settle. If I change
the process I would want it to be just as accurate if not an improvement.

Thanks,
Dave

[Jeremy Braden]

I do not know enought about PID to answer your question directly. Four minutes sounds too long to settle. Have you looked at the shipping examples for the PID toolset? You can find it by opening LabVIEW 6.1 >> help >> find examples >> toolsets and modules >> PID Control >> PID.

[Swimmer]

Yes I have. What I find is that PID tuners never stop tuning. So there is a constant ossilation. We are using a belt ratio from the electric motor to the fixture of about 2.5:1. So any ossilation is magnified by 2.5. So I guess I'm looking for a PID that will stop adjusting the output once within a specified range of the setpt.

Thanks,
DAve