A programmable logic controller (PC) carries out a control algorithm under violations of theontological assumptions (VOA) when the plant does not meet one or more unstated but essential assumptions used in the design of the control algorithm. This paper presents a recovery technique based on the theory of Fuzzy State Fuzzy Output Finite State Machines (FSFO-FSM). The appeal of this approach is that the only known recovery results today are for fuzzy controllers. A common drawback of most linguistic models is that they are essentially static and thus not suitable to model the sequential behavior of a PC program. A FSFO-FSM can act as a sequentialmachine during the normal course of control, yet it possesses all the required linguistic properties during a VOA. This approach can enhance substantially the safety and operational range of existing PC and embedded control applications. This paper describes the control problem, presents results based on simulations, and show architectural constraints when applying this principle to real-world application.