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 and corresponding to a first range of the first signal, 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 and corresponding to a second range of the first signal, wherein the first and second ranges of the first signal do not overlap; determining whether the second signal deviates from the prediction of the second signal to an extent that meets a predetermined condition; and generating a first indicator of an abnormal operation associated with the level regulatory control loop based on whether the second signal deviates from the prediction of the second signal to the extent that meets the predetermined condition.