Abstract: An apparatus for detecting cracks in a flexible rotating coupling is disclosed in which the flexible coupling includes a flexible element having a plurality of flexible discs. An electrically conductive, normally continuous, line is affixed to at least one of the flexible discs and connected to a circuit. The conductive line becomes discontinuous if the disc cracks. The circuit is mounted on the coupling and transmits a signal indicative of the continuous or discontinuous condition of the conductive line and thereby the intact or cracked condition of the flexible disc. The transmitted signal is received by a stationary circuit which provides an output indication of the disc's intact or cracked condition.

Abstract: A communications terminal for use with a programmable controller to permit transmission of status and control information between that programmable controller and a plurality of programmable controllers having similar communications terminals associated therewith and connected in a communications loop. The communications terminal permits one programmable controller to utilize signals originating in other programmable controllers and to provide asynchronous time division multiplexed signals to other programmable controllers via a shielded, twisted-pair conductor to control devices connected to those other programmable controllers.

Abstract: An A.C. electric power usage measuring and display system using microcomputer based digital processing. Power usage pulses optically sensed from a watthour meter rotary disc and time pulses sensed from the 60 Hz A.C. power line are input to a microprocessor that is programmed to calculate and display the day of the week 1 to 7, the time of day on a 24-hour clock basis, the total watthours and kilowatthours since the start of a billing period on a decimal basis, the peak interval watthours and kilowatthours on a decimal basis, the peak interval start time and end time on a 24-hour clock basis for a peak interval of predetermined time, the peak power demand in kilowatts on a decimal basis, the day of the peak demand on a weekly 1 to 7 basis, the time of the peak demand on a 24-hour clock basis, and the present demand in kilowatts on a decimal basis.