A wireless power and communication unit for field devices is configured to connect to a field device and provide operating power and wired digital communication between the unit and the field device. RF circuitry in the unit is configured for radio frequency communication. In one embodiment, power supply circuitry in the unit includes one or more solar power cells that convert solar energy into electricity to power both the unit and the field device. The unit interacts with the field device in accordance with a standard industry communication protocol. The unit communicates wirelessly with an external device, such as a control room, based upon the interaction with the field device.

Wireless power and communication unit for process field devices

Audio perception in local proximity to visual cues is provided. A device includes a video display, first row of audio transducers, and second row of audio transducers. The first and second rows can be vertically disposed above and below the video display. An audio transducer of the first row and an audio transducer of the second row form a column to produce, in concert, an audible signal. The perceived emanation of the audible signal is from a plane of the video display (e.g., a location of a visual cue) by weighing outputs of the audio transducers of the column. In certain embodiments, the audio transducers are spaced farther apart at a periphery for increased fidelity in a center portion of the plane and less fidelity at the periphery.

Techniques for localized perceptual audio

An adapter (300) for coupling to a process control transmitter (308) of the type used to monitor a process variable in an industrial process includes a first connection configured to couple to a first side of a two wire process control loop (302), a second connection configured to couple to a second side of the two wire process control loop (302) and in series with a first connection to a process control transmitter (308), and a third connection configured to couple to a second connection of the process control transmitter (308). Wireless communication circuitry is coupled to at least the third connection and is configured to provide wireless communication for the process control transmitter (308). Intrinsic safety circuitry (460) coupled to at least one of the first, second and third connections is configured to limit transfer of electrical energy to a value which is less than an intrinsic safety value.

Rf adapter for field device with low voltage intrinsic safety clamping

A wireless process communication adapter (14, 30) is provided. The adapter (14, 30) includes a housing (120) having a plurality of openings (150, 152). An end cap (124) is coupled to a first opening (150) of the plurality of openings (150, 152). A field device coupling (122) is disposed at the second (152) of the plurality of openings (150, 152). The housing (120), end cap (124) and field device coupling (122) define a chamber (130) therein. At least one circuit board is disposed within the chamber (130), the circuit board (132, 134) has wireless communication circuitry disposed thereon and is coupleable to a field device (12) through the field device coupling (122). In one aspect, substantially all remaining volume in the chamber is filled with a solid material (136). In another aspect, an explosion-proof barrier (164) is provided in the field device coupling (122). Combinations of the aspects are also provided.

Wireless communication adapter for field devices

In order to detect a defective light source, such as a LED coupled to a DC-DC converter circuit for receiving a power signal, an outage detection circuit comprises a top voltage detector coupled to the LED for detecting a voltage across the LED. The top voltage detector has an top voltage terminal for supplying a top voltage signal. The detection circuit further comprises a differential amplifier coupled to the top voltage terminal for receiving the top voltage signal as a first input signal and coupled to a reference voltage terminal. The reference voltage terminal is configured to supply a reference voltage as a second input signal. The differential amplifier comprises an output terminal for supplying an outage detection signal.

Led outage detection circuit

A peak to peak detector circuit for use in an audio system comprises a first amplifier having an input terminal for receiving an L+R AC audio signal and an output terminal which is serially coupled to a resistor in series with a capacitor for generating a variable dc voltage having a time vs. amplitude relationship corresponding to the input L+R AC audio signal. A clamping diode having a cathode electrode coupled to a reference potential and having an anode electrode coupled to the capacitor operates to limit negative amplitude excursions associated with the variable dc voltage to a predetermined minimal value. A rectifying diode having a cathode electrode coupled to the anode electrode of the clamping diode, and an anode electrode coupled to a second capacitor to charge the second capacitor responsive to the amplitude of said variable dc voltage operates to produce a dc output signal proportional to the peak amplitude of said L+R audio signal.

Alan Anderson Hoover

Papers

Peak to peak signal detector for audio system