Abstract: A current source circuit includes a variable impedance circuit coupling the returns of dual-floating power sources, and is configured to limit maximum current output in the event of fault and facilitate detection thereof. The first power source powers the current loop using its source, with the current loop returning through the second power source's return. Control circuitry detects an increase in current beyond the predetermined maximum and appropriately increases the impedance between the first and second power sources returns to limit current provided to the current output to the predetermined maximum. This amount of current is detected by, for example, analog to digital conversion and the fault can thereby be appropriately signaled.

Abstract: A field controller for use in a distributed control system including an area controller and at least one field controller. The field controller manages at least one controlled device in an industrial process operation. The field controller comprises a processor module segment through which it can control a selected number of devices, and it may also include one or more expansion module segments to enable it to control a larger number of controlled devices. The processor module segment includes a processor module and at least one local interface module for interfacing to a controlled device, and the expansion module segment includes interface modules for interfacing to other controlled devices. In the processor module segment, the processor module and said local interface module are interconnected by a bus segment, which is also connected to an upstream off-module connector.

Abstract: A method of calibrating a multivariate controller in a coordinated control system of an electric power generating station includes an expert system for collecting data at a plurality of operating parameters of the power generating system and providing that data to a characterizer block. By using the calibration data, which is predictive of the response of the power generating system to an external disturbance, the characterizer block provides a feedforward signal to the multivariate controller before the effect of the external disturbance can propagate throughout the power generating system. In the method of the invention, the expert system is implemented as a spreadsheet with a DDE interface to the power generating system and an automatic script file generator for communicating to the characterizer block.

Abstract: A continuously controlled current increasing charge pump having n series-connected input capacitors coupled to a voltage/current source for developing a constant output voltage of at least ##EQU1## and an output current I.sub.o =nI.sub.in. Regulating circuits are also disclosed to regulate the output voltage. The charge pump consists of plural input switches that switch alternately the positive and negative sides of a like plurality of series-connected capacitors onto at least one output switch and output capacitor. The output switch is synchronized with the input switches and alternates between the negative and the positive output side of each capacitor.

Abstract: A current conversion circuit having multiple voltage levels with CMOS gates that switch the output capacitors so as to be coupled to the input of another voltage level to move the charge from one voltage level to another voltage level and thus increase the output current while decreasing the output voltage.

Abstract: A method of reducing noise in a mass flow measuring system includes equalizing the ratio of stiffness to mass of a sleeve located in a flow path to the ratio of stiffness to mass of a rod located within the sleeve. The method further includes recognizing a frequency signal from two capacitive sensors mounted to sense axial deflection of the sleeve relative to the rod. The frequency signal is twice the frequency signial from two capacitive sensors mounted to sense lateral deflection of the sleeve relative to the rod. An output of the capacitive sensors for sensing lateral deflection is connected to a conductance circuit and an output of two additional capacitive sensors mounted to sense lateral deflection is connected to the another conductance circuit. The method includes adjusting an output of one of the conductance circuits such that the sum of the outputs is zero.

Abstract: A pressure transmitter apparatus having a unitary body portion, separate diaphragms and flange elements and disposed within the body, a first and second normally vertical pressure passage. The first and second pressure passageways communicate respectively between first and second pressure openings extending normally horizontally through the body portion, and a transducer mounting element. The mounting element, coupled to the body portion and located above the pressure passageways, mounts a transducer that generates a differential pressure signal. One or a pair of diaphragm elements are configured to form first and second process diaphragms, closing first and second pressure openings. The flange element overlies the diaphragm element and is removably and replaceably secured to the body portion.

Abstract: An I/O device in the form of an internal dongle includes a body having connective structure being arranged to removably attach the body to a housing of an electronic device. The dongle also includes a circuit assembly that has an exterior connector on the body for electrically connecting to a second electronic device, a dongle circuit being electrically coupled to the external connector through the body, an electronic cable having a first end electrically coupled to the dongle circuit, and a second end being structured and arranged to connect to an electronic component of the first mentioned electronic device within the housing.

Abstract: A magnetic flowmeter has a tube for supporting fluid flow including a circuit for indicating when the tube is empty to prevent an erroneous flow signal from being provided by the flowmeter, as well as a diagnostic circuit indicating when electrodes in the flowmeter are partially fouled. The circuits include an amplifier connected to two electrodes in the tube and a variable resistor. In a normally operating mode, the amplifier produces an oscillating signal when the tube is empty, and in a diagnostic mode, the amplifier produces an oscillating signal when the electrodes are partially fouled.

Abstract: An industrial computing device includes a field mountable primary housing having a removable side cover to facilitate expansion. Within the primary housing there is a head board having a processor on one side. On the opposite side, there is an expansion connector adapted to receive an expansion board and at least one peripheral connector, which is coupled to the processor within the housing. The peripheral connector receives at least one PCMCIA card such that the PCMCIA card is also within the housing when plugged into the peripheral connector. The expansion board includes at least one more peripheral connector to receive at least one more PCMCIA card. The peripheral connector, the expansion connector and the side cover are oriented orthogonal to a mounting plane of the computing device. The primary housing can also include a removable front cover, which together with a top or bottom portion of the primary housing, provides an aperture for flush-mounting an I/O device in the form of an internal dongle.

Abstract: A Keypad Annunciator Graphical User Interface, (KAGUI), for use by an operator of a process control system for presenting and responding to alarm state data generated by the process control system, is disclosed. The KAGUI provides an interactive display of a keypad annunciator on a monitor display screen. A panel manager display and a dynamic icon enhance operator awareness, in a multi-window display environment, of alarms. The KAGUI synchronizes alarm data presented by the KAGUI with process control system alarm data and informs the operator of the status of interprocess communication.

Abstract: A single-sided differential pressure sensing chip having a cavity formed in the top surface of a substrate, a deformable diaphragm spanning the cavity, and a pressure passage connecting the top surface of the substrate with the cavity, and a method of making the same are described. A first fluid pressure applied to the top surface of the substrate in the vicinity of the diaphragm exerts a force on the top surface of the diaphragm, and a second fluid pressure applied to the top surface of the substrate near the pressure passage exerts a force on the bottom surface of the diaphragm. The diaphragm deflects in response to the forces exerted upon it, and a sensing element detects the flexing of the diaphragm. The pressure sensing chip can be contained within a housing structure formed of a carrier and a cap.

Abstract: Methods and apparatus for the concurrent display of two or more property pages of a Graphical User Interface (GUI) are disclosed. A user can select a property page displayed by a first property sheet system and create a second property sheet system that displays the selected property page at second, user selected display position. Alternatively, the user can place, or dock, the selected property page into an existing property sheet system for inclusion therein and display thereby. The first property sheet system displays, at a first display position, any of the property pages remaining therein. Typically, the selected property page is removed from the first property sheet system and the first property sheet system is destroyed if it contains no other property pages. The invention allows a user of a GUI to concurrently display and interact with multiple property pages of multiple property sheet systems for optimizing the exchange of information with the GUI.

Abstract: A field mountable controller boots by transmitting a seed letterbug to a server. The server responds with an initial operating system and program. The program reads configuration information about the controller and transmits it back to the server which responds with a particular letterbug for the controller. The controller then transmits the letterbug to a boot image server which returns a corresponding operating system image to the controller. The controller then boots using the operating system.

Abstract: Drivers and sensors in Coriolis-type mass flowmeters are used to monitor and predict flowmeter failure modes due to mechanical deterioration during meter operation. The relative values of two different signals, e.g, resonant frequencies, associated with Coriolis flow conduit motion are monitored as an indicator of excessive mechanical deterioration and also used to compensate for shifts in meter factor. The noise spectrum of the sensor output is also monitored to indicate mechanical fatigue of the tubes. Energy loss in the vibrating tubes is monitored as an indication of fatigue to determine tube failure by determining the drive power needed to maintain constant velocity oscillation or measuring the decay rate of the drive signal when driver power is interrupted.

Abstract: In a process control system, a user selects a displayed object. The user then asks to be shown documents related to the selected object. A list of related documents is automatically displayed to the user who may then select a document for display. The association of documents with displayed process control objects is facilitated by a document librarian. Within the document librarian, a user drags documents from within a document hierarchy over to hierarchically designated objects within the process control system, and drops them thereon. Links between the documents and the process control objects are thereby established.