Inventors:
Peter R. Wohld - Glen Ellyn IL
International Classification:
G06F 1546
G01M 1900
Abstract:
An evaluation unit accurately measures the elapsed time between two events. The two events mark the start and stop points of a switching device, such as a motor-operated valve, as it is switching between a first state and a second state. This elapsed time, when compared to a base-line elapsed time or a previously measured elapsed time, provides an indication as to whether the performance of the device has degraded to the point where maintenance or replacement of the switching devices required. The unit includes electro-optical means for individually sensing the occurrence of each event, logic means for selecting the occurrence of either event as the starting or stopping point for the time measurement, and a timing circuit for performing and displaying the time measurement. In one embodiment, the unit includes a microprocessor that processes and stores the time measurements for subsequent retrievel by an external central processor, which processor is programmed to analyze the timing data and generate reports that specify performance criteria associated with the switching device under evaluation.