Abstract: A plurality of operating systems in buildings organized in geographical groups, each group having a local service office, are monitored at both the local offices and a central office for the presence of various combinations of performance criteria defining alarm conditions.

Abstract: A method and apparatus for determining the absolute compression pressure of each cylinder in an internal combustion engine is disclosed. The technique involves analyzing the changes in engine kinetic energy in order to calculate both the work of compression and expansion of each cylinder in a multi-cylinder engine typically during a decelerating engine cycle. Speed data is obtained and the work associated with the compression and expansion process for each cylinder is calculated and compared to the compression and expansion data of a good engine which is stored in computer memory. If a compression fault is present, it can be detected because that cylinder will display a decrease in both the work of compression and expansion. Once a faulted cylinder has been identified, the magnitude of the fault can be calculated and normalized and the compression pressure of each cylinder calculated and displayed.

Abstract: In a position measurement system having a plurality of redundant pulsed light sources, detectors, control circuits, signal conditioning circuits, and signal processors, but having space available for only a single encoder for measuring the position of a monitored device, the pulsed light sources emitting light of different wavelengths which are combined in wavelength multiplexed fashion at the encoder, the combined light then being split for encoding and recombining in time domain multiplexed fashion, the recombined light then being split for filtering of the different wavelengths at the plurality of light detectors each of which provide signal manifestations indicative of the position of the monitored device according to the encoded light pulses of the particular wavelength monitored to the associated control and signal conditioning circuits for transmittal to an associated signal processor.

Abstract: A conventional regenerative comparator is modified by including a transistor switch in the feedback network to open circuit the feedback path according to the output state of the comparator, and by biasing the noninverting input of the comparator with a voltage directly proportional to the amplitude of the input signal, thereby providing variable threshold comparator with a hysteresis transfer characteristic with two distinct state change threshold levels that are a fixed ratio of the amplitude of the input signal.

Abstract: A power loss analyzer for providing a signal processor with a discrete power loss alert signal indicative of an imminent power disruption and for providing to the processor subsequent to a disruption a discrete power loss signal indicative of a power disruption that has resulted in degradation of the data stored in memory is disclosed.

Abstract: A plurality of two-plate capacitive pressure sensors with low parasitic capacitance and easily accessible plates are made with microcircuit and thin film technology by depositing a thin layer of glass over a plurality of thin, rigid plates and thin, narrow electrodes previously deposited on a thick glass dielectric substrate, by etching cavities in the thin layer of glass over the plates, and by anodically bonding, in vacuum, thin, doped silicon diaphragms to the thin layer of glass to form variable capacitors each of whose capacitance varies with the pressure outside the sensor.

Abstract: An improved PBA shutdown monitor circuit senses collective pitch control position rate of change magnitude and inhibits PBA shutdown in response to the continuous presence of sensed magnitude within a range of selected collective pitch rate magnitudes bounded by a slow rate limit signal value and a fast rate limit signal value.

Abstract: An ion/electrostatic probe for an afterburning gas turbine jet engine comprises an afterburner flameholder (24) electrically insulated from other engine parts by means of non-electrically-conductive support rods (30, 45) or by means of electrically conductive rods (30) insulated (50, 52) from the engine case (12). An electrical connection (54) may be brought through the engine case. The flameholder (24) may be insulated (70) from an attached igniter.

Abstract: Low reflectivity electrodes (2, 7) are provided on semiconductive and piezoelectric substrates (1, 6) including a layer (3, 9) of gold-germanium mixture and a layer (5, 8) of raw gold, or only a gold-germanium mixture (10), the total germanium content of the electrode comprising approximately 2%-3% of the total gold and germanium content of the electrode, and the thickness of the electrode being on the order of 1% of the acoustic wavelength.

Abstract: The flexible membrane for sensing a differential pressure in a cylindrical sensor is made from a tube with heavy end rings that gradually taper down to form a flexible membrane such that stresses from membrane flexions are distributed throughout the end rings to prevent the stresses from being transmitted to the joints between the tube and its supporting structure thereby reducing hysteresis and creep deformation effects; temperature and stray capacitance effects are minimized by using the capacitive sensor in a tank circuit having an inductor integral to the transducer structure, the tank circuit oscillating at its resonant frequency for use in indicating the differential pressure.