even adaptively sized regions based on the sensitivity of the outputs to input variations at respective portions of the input space the control system also provides a set of special modes for system startup and shutdown these are distinct from the normal operational modes in that energy efficiency is not generally a primary consideration during these transitions and because other control issues may be considered important these modes also provide options for control system initialization and fail safe operation it is noted that since the required update time for the system is relatively long the neural network calculations may be implemented serially on a general purpose computer e g an intel pentium iv or athlon xp processor running windows xp or a real time operating system and therefore specialized hardware other than the data acquisition interface is typically not necessary it is preferred that the control system provide a diagnostic output 236 which u201c explains u201d the actions of the control for example identifying for any given control decision the sensor inputs which had the greatest influence on the output state in neural network systems however it is often not possible to completely rationalize an output further where the system detects an abnormal state either in the plant being controlled or the controller itself it is preferred that information be communicated to an operator or service engineer this may be by way of a stored log visual or audible indicators telephone or internet telecommunications control network or local area network.