A fairly common stumbling block for those new to controller tuning relates to step 2 of the controller design and tuning recipe. Step 2 says to "collect controller output (CO) to process variable (PV) dynamic process data around the design level of operation." But suppose disturbance rejection is our primary control objective? Shouldn't we then step or pulse (or "bump") our disturbance variable to generate the dynamic process test data we require? The short answer is, no. Tuning a feedback controller based on the disturbance to measured process variable dynamic relationship is a certain path to failure...
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