| 摘要 |
A detector/annunciator circuit for monitoring the status (opened or closed) of field process switches. A two lead "End of Line Device" (ELD) is field mounted proximate the switch, and, during normal operation, detects switch status and transmits this information to panel mounted logic that decodes and annunciates the information. If the ELD's lead wires become open or short circuited, or are subjected to a ground fault, the panel mounted logic can identify the fault, diagnose its type, and annunciate such, thus aiding system troubleshooters.
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