SYSTEM CONTROLLER AND REMOTE FAULT ANNUNCIATOR WITH COOPERATIVE STORAGE, SHARING, AND PRESENTATION OF FAULT DATA

摘要

An annunciator for the conduction status of individual switches (15) wired into a series circuit records this status as status history at regular intervals in a memory (69). The status history is preferably recorded as individual entries having the identification number of an open switch (15) along with a time stamp specifying the length of time which that switch (15) has been open. The current entry is recorded in the mem- ory (69) and a new entry started each time the switch (15) for which an entry in the memory (69) is being created closes or a switch (15) currently receiving power opens. A controller (40) separate from the annunciator generates a request signal and provides a request time value to the annunciator specifying the time which has elapsed since the request condition was detected. The annunciator uses the request time value to de- termine the probable switch conduction status at the time of the request.