Scan Checking

a type of automatic check in which one measuring device is connected in turn to the transducers of each of the values being checked. During the process, the input switch (usually with programmed control) sequentially connects the transducers to a common checking junction point, which compares the values obtained with the specified values in order to detect deviations in both directions, performs digital transformations on the incoming signals, and processes the incoming information. In many cases the deviations in the higher and lower zones are further divided into undesirable and unacceptable values.

The number of points checked may be as great as several thousand; the scanning rate is dictated by the dynamic characteristics of the process being checked and by the technical capabilities of the input switch and the data-processing system. The results of the checking may be sent to a common output control board (with indications of the number of the parameter being checked) or to separate output control units through a switch operating in phase with the input switch. Scan checking is used for integrated antomation of production processes and in remote-control telemetry systems.