1. A method for detecting abnormal operation associated with a level regulatory control loop, comprising: generating a first signal associated with regulatory control of a level of material in a tank; generating a second signal associated with regulatory control of the level of material in the tank; using a first model to generate a prediction of the second signal as a function of the first signal, the first model including a first regression model in a first range corresponding to a first operating region of the level regulatory control loop, the first model capable of being subsequently configured to include at least a second regression model in at least a second respective range corresponding to at least a second respective operating region different than the first operating region; determining whether the second signal significantly deviates from the prediction of the second signal; and generating a first indicator of an abnormal operation associated with the level regulatory control loop based on whether the second signal significantly deviates from the prediction of the second signal.