When does the PID integral integrator total reset? (Integral Windup)
We are using the BMIStandard.PIDCtrl controller for our PID control.
I assume they have anti integral windup code incorporated into the control algorithm.
Is the integral integrator reset when the controller output either reaches its Min and Max output limits (adjustable from the controller faceplate) or when the controller is switched to manual?
In our cascade controllers and cases where we switch between controllers to drive the final control element we have been switching the in-active controller to manual mode and forcing the output to track the live controller.
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I think the anti-windup only limits the overrun at the Output Range itself (RealIO Min/Max) and probably you'll still see some lag, as it is not a direct limit on the value.
What you should see when changing the mode from manual is a direct reset of the Integrator to match the Output Value (this has actually nothing to do with wind-up), but sounds like exactly what you want to have when switching between multiple Controllers.
I agree with Rob's comment, if you need Cascade Loops it could be you require "CC" connections and more advanced Controllers like "PIDAdvancedCC" from ControlAdvancedLib.
by Rob Lyon
I'm not familiar with the BMI version of the AC800M PID controller. However, there are some known issues with BackTracking when a cascade slave PID hits an output limit which can cause unexpected behaviour in the Master.
What EXACTLY are you seeing ?
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