Selective process data logger with instant replay

Abstract

This is a system to record process data only when it has changed enough to be significant to the process being controlled and monitored. Unlike conventional fixed interval data loggers it does not miss a significant event which occurs between fixed time interval data sets. Neither does it fill its memory with repetitive constant data values. The time for data recording is determined by the process behavior and not known in advance. For this reason the time at which a data set was recorded is included within it. This system has a clock calendar, non-volatile memory, microprocessor control, and data replay and display capability. Data can be replayed on the included display using simple reverse and forward buttons to sequentially scan through data records in the non-volatile memory just as if it were a tape recording. A system can be incorporated into process controls to substantially increase their utility.

Dependencies are inferred from the claim text.