Abstract: Microminiature resonant sensor structures are prepared according to micromachining/microfabrication techniques, which structures include thin-film deposits of piezoelectric materials. Such piezoelectric deposits may be excited electrically by including metallized conductive paths during fabrication, or optically. The resonant frequency of the sensor structure is varied by subjecting it to a physical variable, or measurand, such as pressure, temperature, flow rate, etc. Similarly, the resonant frequency of the devices may be detected electrically or optically. The microminiature resonant structures include ribbons and wires, hollow beam and cantilevered hollow beams, and single- and double-ended double beam resonant structures such as tuning forks.

Abstract: A double-tuning-fork (DTF) resonator having electrical circuitry operable, if either tine breaks, to develop a characteristic electrical circuit condition which is detected to produce an indication of failure. In one preferred embodiment, the circuitry includes a dual series circuit for energizing the electrodes on the DTF tines, with (1) a first series circuit passing down one tine to the remote end thereof, across the support segment at that end of the DTF, and back up the other tine, and (2) a second series circuit passing down the other tine to the remote end thereof, across said support segment at that end, and back up the first-mentioned tine. If either tine breaks, or if there is fracture of another part of the DTF carrying an electrode energizing lead, vibratory excitation of both tines ceases, and the output signal is caused to go to a level (e.g. zero) clearly indicating failure of the instrument.

Abstract: In a combustion system, the economic optimum efficiency is achieved by periodically computing a relative index of combustion efficiency using the combustion chamber as a real-time, on-line calorimeter. This is accomplished by first determining the combustion chamber inputs and outputs required to calculate a relative index of performance (including measuring the amount of heat released or work performed at the present air/fuel ratio including the stack losses, without oxygen and/or carbon monoxide sensors), sequentially comparing the latest relative index value with the previous value, then adjusting the air/fuel ratio to achieve an improved index value.

Abstract: An optically driven, electromagnetically oscillating resonant sensor subjected to a stress force wherein the optical driving energy and the optically communicated signal generated in response to the stress force are both communicated a substantial distance along a single optical fiber. A portion of the supply energy drives the oscillatory mechanism and a portion is reflected to a frequency detector by the shuttering action of the resonant element. The device may be configured so as to be electrically driven and optically sensed, optically driven and electrically sensed, or both optically driven and optically sensed for maximum retrofit versatility in past, present, and future process control systems.

Abstract: A language structure and translator specifically adapted for use in constructing computer programs for controlling chemical and physical processing. The translator converts to compilable code programs written as statements expressing control intentions or results. Each textual function and statement is expressed as a data structure which expresses the function, as configured, and the state and values most recently calculated for the relevant variables. Provision is made for treating the program structure (i.e., control connections, program order and components, etc.) as a part of the dynamic state of the application. Graphical symbols, or icons, are employed to draw the eye to critical features in the control program and to lead the eye through critical interrelationships among the several commands of a complicated control system. At the same time, the translator treats the keystrokes generating these icons as statements (i.e.

Abstract: Light from a source is communicated to a measurand site. Interferometric means located at the measurand site modulates the light by means of a resonator, the frequency of which is related to the measurand value, said resonator being driven by the modulated light to provide localized oscillator loop closure at the measurand site. Embodiments are disclosed using modified Fabry-Perot and Michelson interferometer designs.

Abstract: Cut point is controlled in a distillation process by monitoring the partial pressure in a stripper.

Abstract: Beamsplitter means for directing light in a Michelson interferometric drive and frequency sense scheme for use with a mechanical resonator. In a first embodiment a special prism is used. In a second embodiment a four-port coupler is used.

Abstract: A calibration apparatus and associated method for the measurement of valuable fluids in storage or at the point of transfer. More particularly, a calibration apparatus and method for use with capacitive liquid level measurement systems.

Abstract: Vibrating resonant mechanical structures are excited optically by photokinetic energy transfer and detected optically. In particular, a tuning fork sensor measuring a physical parameter is excited into oscillation by radiant energy and the frequency of vibration is detected by radiant energy which may be communicated via an optical fiber. These vibrations are communicated via a fiber optic to a detection location.

Abstract: A differential-pressure transmitter having a range diaphragm and a slack diaphragm to receive process pressures and to apply such pressures to an interior sealed chamber containing a fill-liquid. An internal passageway between the regions adjacent the diaphragms provides for transfer of fill-liquid in response to differential pressure changes. The passageway serially includes a vertically-oriented tube containing a ball of magnetic material and surrounded by a solenoid winding. Energization of the winding lifts the ball to the top of the tube. When the winding is de-energized, the ball drops down through the fill-liquid to create a reference pressure pluse which is directed to the range diaphragm to correspondingly alter the instrument output signal. The output signal is monitored to check the span calibration, and adjustments are made as needed.

Abstract: Reading values, setting values and setting configuration options within a complex programmable apparatus is simplified, by chaining all user interaction points into a single path, cross linking portions of the main path into subpaths and providing keys that step the user according to his selection along the main path, along the subpaths, and between the subpaths. A two part display indicating the general and specific positions clarify the locations and the options available.

Abstract: A differential-pressure instrument the body of which forms a sealed interior pressure chamber containing a fill-liquid and includes a pair of flexible diaphragms to apply to the fill-liquid an input differential pressure to be sensed by an IC strain-gauge chip within the chamber. A spring plate divides the interior pressure chamber into two sections and is deflectable in response to differential pressures. Overrange pressure protection is provided by a valve which is closable by an elastomeric pad carried by the spring plate when the plate deflection reaches a pre-set amount. Valve closure locks the fill-liquid in place alongside the plate to provide an incompressible liquid back-up preventing further deflection of the plate, thus preventing further increases in differential pressure across the IC chip. In one embodiment, valves are placed on both sides of the spring plate to protect against both high-side and low-side overrange pressures.

Abstract: A micromechanical electric shunt is fabricated by micromachining according to recent IC fabrication procedures. A plurality of such shunts is incorporated on a single substrate to form novel process station or post identification or signature encoding apparatus for use on a telecommunications bus or the equivalent. Such identification of signature encoding apparatus may be configured for conventional binary coding. Both frequency and current derivative mode apparatus are disclosed.

Abstract: Differential-pressure measuring apparatus comprising a casing providing a closed chamber filled with fluid and divided into two sections by a pressure-responsive element. The input pressures are applied to the two chamber sections respectively to develop a corresponding force on the pressure-responsive element. A sealed evacuated housing of non-magnetic material is in one chamber section and contains a double-tuning-fork (DTF) the resonant frequency of which varies with longitudinal tension force applied to the DTF. The force developed by the pressure-sensitive element is coupled by magnetic elements through the wall of the housing and to the DTF so as to control the resonant frequency of the DTF in accordance with the differential pressure to be measured. The DTF is activated to produce an output signal reflecting the differential pressure.

Abstract: The Swinging Door Method of compressing an industrial process data stream is described. Data used for generating a line graph is compressed for display or storage while preserving maximum, and minimum values, and other valuable data features. The method establishes offsets from a first point which then defines a corridor opening. Subsequent points are received to refine the defined error band or corridor direction until a point is received that cannot be included in the corridor. An end point for the corridor is then generated. The corridor end points then replace the intervening raw data as the output.

Abstract: A method for patterning a photoresist or insulating layer on a printed wiring board utilizes two photoreactive coatings comprising a photoprocessable ultraviolet (UV) sensitive layer overlaid with a thin, unexposed, undeveloped strip base silver film. A white light x-y plotter, preferably employing an octagonal aperture, is driven directly from a CAD system to expose the film on the board in the desired pattern without affecting the underlying UV sensitive layer. The film is then developed on the board and employed as an in situ mask for the underlying UV layer during exposure of the board to a UV flood lamp. After UV exposure the film is peeled off to allow conventional processing of the selectively polymerized layer. This technique produces high resolution, inspectable onboard masks in full registration using reliable low energy plotters.

Abstract: Reading values, setting values and setting configuration options within a complex programmable controller is simplified, by chaining all user interaction points into a single path, cross linking portions of the main path into subpaths and providing keys that step the user according to his selection along the main path, along the subpaths, and between the subpaths. A two part display indicating the general and specific positions clarify the locations and the options available.

Abstract: A differential-pressure transmitter having a range diaphragm and a slack diaphragm to receive process pressures and to apply such pressures to an interior sealed chamber containing a fill-liquid. An internal passageway between the regions adjacent the diaphragms provides for transfer of fill-liquid in response to differential pressure changes. The passageway serially includes a vertically-oriented tube containing a ball of magnetic material and surrounded by a solenoid winding. Energization of the winding lifts the ball to the top of the tube. When the winding is de-energized, the ball drops down through the fill-liquid to create a reference pressure pulse which is directed to the range diaphragm to correspondingly alter the instrument output signal. The output signal is monitored to check the span calibration, and adjustments are made as needed.

Abstract: Apparatus for converting an analog-format electrical signal or quantity (such as the magnitude of an electrical circuit element) into a corresponding pulse-format signal, preferably in the form of a train of periodic pulses the lengths of which are controllable as a percentage of the cyclic period. A pulsed duty-cycle signal is developed in a negative feedback loop around an integrator having an analog-format input signal. The integrator output controls the d-c level of an up-and-down ramp signal which is fed to a comparator to produce pulses during the times the ramp voltage is above (or below) the firing threshold of the comparator. These pulses control a switch between the integrator input and a reference voltage so as to produce a negative feedback signal for the integrator.