General Electric Company

Ge Intelligent Platforms Inc.

Bruce C Henderson

Alan Carroll Lovell

Daniel Milton Alley

Ye Xu

Longhui Shen

Vitaly Alexandrovich Tkachuk

Rainer Hanisch

A system for coupling a modulated voltage signal onto a current loop between a host device and a field device, in various embodiments, can include a circuit and an impedance bridge. The circuit is configured to flow current from the field device between two terminals of an input circuit in the host device, wherein the two terminals are included in the current loop. The impedance bridge is positioned between the two terminals and configured to modulate impedance to convert the current in a field loop produced by the field device into terminal voltage modulation, without introducing a DC voltage burden to the current.

Methods, systems, and devices for coupling a modulated voltage signal to a current loop using a variable impedance bridge

A system and method according to various embodiments can include a programmable current sink circuit that comprises a digital-to-analog converter (DAC). The DAC is programmable to set an adjustable magnitude of current sink so that a proper amount of current is jointly sunk from a plurality of inputs to generate a total sink current. With the adjustable current sink, redundant inputs, such as dual modular redundancy or triple modular redundancy, or simplex inputs can jointly sink the proper amount of current.

Programmable current sink for contact input circuits

Provided is programmable circuit for interfacing with a field device. The circuit includes only one analog-to-digital converter (ADC) configured to receive from the field device one from the group including a current signal and a voltage signal. The received one signal has frequency shift keying tones (FSK) superimposed thereon, the ADC being configured to extract information from the received one signal and the FSK tones simultaneously. Also included is only one digital-to-analog converter configured to drive an output signal to the field device, the output signal (i) including one from the group including a current signal and a voltage signal and (ii) being summed with an FSK-modulated signal.

Universal input and output interface

Systems for communicating over a communication interface are provided. An integrated circuit includes circuitry for monitoring a current flowing between two terminals of the integrated circuit. The integrated circuit also includes a voltage driver circuit for modulating a voltage between two terminals of the integrated circuit. The voltage driver modulates the voltage across the two terminals of the integrated circuit to encode data according to the Highway Addressable Remote Transducer protocol.

Current loop voltage modulator for communication interface

A digital filter for a power system stabilizer in a generator power system. The filter comprises a multi-stage filter having a low DC gain, a phase lead in the region of power oscillations (approximately 0.1 to 2 hertz) of the power system, a torsional reject characteristics (approximately 13.5 to 45 hertz) associated with mechanical resonances of the system, and high attenuation at the fundamental power frequency (e.g. 60 hertz). The filter is comprised of four digital filter sections, the first providing a lead and lag characteristics, the second and third providing a torsional reject characteristic, and the fourth providing a substantially zero DC gain characteristic for the elimination of any DC signal offset as well as a line freqeuncy notch, which tracks the fundamental line frequency. The first section, moreover, comprises a separate stage so that its characteristic can be independently adjusted in the field while the second, third and fourth sections are combined in a composite stage whereby the band reject and signal notch requirements are implemented.

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Troutville, VA, United States of America

Bruce C Henderson