Advanced Control Algorithms: Beware of False Prophecies 47 4. Was the PID controller tuned with a reputable method, such as the Ziegler Nichols closed-loop or reaction curve method with the controller gain halved to suppressed oscil- lations? If not, the comparison was unfair; tune the PID controller properly and try again. After these steps, you may still have an insatiable desire to use something more sophisticated than PID control. If so, compare the performance of any proposed algorithm with a PID controller, based on the check points in Table 4-1. Assuming that your high-tech algorithm passes the check points, please do one more thing. Make sure that the controller being used to implement the fancy strategy is self-tuning--initially and when- ever loop gains or dynamics change. No matter how good the algo- rithm is supposed to be, it won't work unless it is well-tuned. And, surely, nobody is left outside the funny farm who would willingly volunteer to learn a new set of tuning adjustments, then use them manually every time the plant started up or was subject to a change