Abstract: A method for determining the pulsatile flow characteristics in fluid flow driven by a periodic pressure disturbance includes the step of evaluating the spectrum of a signal representative of the vortices generated by a vortex flowmeter. Because of the periodic pressure disturbance, the signal is an FM signal in which a carrier, having a frequency corresponding to the vortex-shedding frequency in the absence of pulsating flow, is modulated by the periodic pressure disturbance. The pulsation frequency and amplitude are then estimated on the basis of the separation between adjacent sidebands of the spectrum of the FM signal and the relative amplitudes of the sidebands.

Abstract: A digital flowmeter includes a vibratable conduit, a driver connected to the conduit and operable to impart motion to the conduit, and a sensor connected to the conduit and operable to sense the motion of the conduit. A control and measurement system is connected to the driver and the sensor. The control and measurement system includes circuitry to receive a sensor signal from the sensor, generate a drive signal based on the sensor signal using digital signal processing, supply the drive signal to the driver, and generate a measurement of a property of a two-phase material flowing through the conduit based on the signal from the sensor.

Abstract: A method for changing the difference between the number of active controlled variables and the number of available manipulated variables in a multivariate control system. Controlled variables can be adaptively classified into one of an ordered plurality of classes, with each class having a rank that defines its position within the order. If the number of active valid controlled variables exceeds the number of available manipulated variables, the active controlled variables from the lowest ranking class having active controlled variables are then deactivated according to a predefined priority order by setting their associated setpoints equal to their measured values. Otherwise, inactive controlled variables from the highest ranking class having inactive controlled variables are reactivated according to the same predefined priority order by setting their associated setpoints to the desired setpoint values.

Abstract: A digital flowmeter includes a vibratable conduit, a driver connected to the conduit and operable to impart motion to the conduit, and a sensor connected to the conduit and operable to sense the motion of the conduit. A control and measurement system is connected to the driver and the sensor. The control and measurement system includes circuitry to receive a sensor signal from the sensor, generate a drive signal based on the sensor signal using digital signal processing, supply the drive signal to the driver, and generate a measurement of a property of a two-phase material flowing through the conduit based on the signal from the sensor.

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: In a position control system for monitoring the position of a valve, a signal transmitter for generating a signal indicative of a valve position includes a shaft coupled to the valve and rotatable to an azimuth angle indicative of the valve position. The signal transmitter includes a signal flag mounted on the shaft in either a calibration state or an operating state. In the calibrating state, a signal-flag adjuster sets the azimuth angle of the signal flag independently of the shaft or of any other signal flags. In the operating state, the signal flag rotates with the shaft.

Abstract: Information is transmitted to a network by a system which receives data from a first processor into a first FIFO and from a second processor into a second FIFO. Data exiting the first FIFO is discarded. As data is received into second FIFO, data exiting the FIFO is transferred to the network. When and end-of-message indication is detected in the received data, the contents of the FIFOs are compared. If a miscompare occurs, transferred data from the second FIFO to the network is caused to be in error. Accordingly, a message sent to the network from the second FIFO will be rejected either by the network or by a receiving node.

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 operator workstation has a worksurface and left and right upper support members extending upward from the worksurface. Multiple flat-panel display units are mounted between the support members above the level of the worksurface. The displays are mounted above one another, between the support members. Lower support members support the workstation in connection with a base mounted between the lower support members. The base has a substantially triangular cross-section, while the lower support members have a substantially triangular shape.

Abstract: The invention relates to a vortex flow meter for ultra pure applications. The vortex flow meter of the invention employs a smooth and continuous fluorocarbon layer to coat a number of fluid accessible surfaces of the flowmeter. The coating prevents or minimizes contact between the process fluid and the fluid accessible surfaces of the flowmeter, thus allowing the flow meter to measure the flow rate of a process fluid having a level of purity of typically one part per trillion without contaminating the fluid. The flowmeter of the invention is advantageously less costly and more accurate than conventional flow meters for ultra pure applications.

Abstract: A pulse width modulation (“PWM”) generation circuit is described. The circuit includes a main PWM generator, a trimming signal generator, and a summer. The main PWM signal generator generates a main PWM output which is modified by the summer in accordance with a trimming signal produced by the trimming signal generator. In particular, the main PWM signal may be lengthened, shortened, or preserved by the summer circuit. Accordingly, the main PWM signal is trimmable, without direct modification thereof by using the trimming signal generator.

Abstract: Equipment storage apparatus, such as equipment racks and cabinets, according to the invention have a vertical load bearing member with a stepped cross-section. Thus, for example, a load bearing member of a frame according to one aspect of the invention can have two faces on its front: one with a frontward directed normal for accommodating equipment mounts, and one with a frontward directed normal for accommodating front door mounts. A pair of such load bearing members can be provided, along with one or more horizontal cross-pieces or other such structural elements, to form a frame defining a generally rectangular central region in which mounted equipment is disposed.

Abstract: A digital signal processing system operating in conjunction with a vortex flowmeter passes a digital representation of a flowmeter signal into a multistage decimator having two outputs. The two outputs correspond to the vortex flowmeter signal downsampled to two different sampling frequencies. One of the two outputs passes to an on-line channel having an adaptive bandpass filter for tracking the fundamental frequency of the vortex flowmeter signal, thereby continuously monitoring the flow rate. The other of the two outputs passes to an off-line channel having a tunable bandpass filter that can be used to observe frequency components other than those near the fundamental frequency. The system thus enables maintenance personnel to conveniently monitor the noise spectrum generated by the flow without interrupting the operation the flow measurement.

Abstract: An operator workstation has a worksurface and left and right upper support members extending upward from the worksurface. Multiple flat-panel display units are mounted between the support members above the level of the worksurface. The displays are mounted above one another, between the support members. Lower support members support the workstation in connection with a base mounted between the lower support members. The base has a substantially triangular cross-section, while the lower support members have a substantially triangular shape.

Abstract: An article adapted to pass a cable through a housing includes a substantially solid body, including front and rear ends. A side surface of the body provides a groove extending into the body from the front to the rear end. The groove is sized to carry a selected size electric cable. The body also includes connective structure adapted to removably connect the body to the housing. The article also includes a sheet of nonconductive material extending across the groove at the front end of the body. The sheet provides a circular opening sized to allow the cable to pass therethrough. The sheet also has a slit extending from the side surface to the circular opening. The sheet is fabricated of a resilient material and is structured to allow the cable to be inserted through the slit and into the circular opening such that the cable extends along the groove and extends into the housing from the rear end of the body when the body is connected to the housing.

Abstract: A computer is connected to redundant network switches by primary and secondary connections, respectively. Test messages are sent across each connection to the attached switches. A break in a connection, or a faulty connection, is detected upon a failed response to one of the test messages. In response to this failure, traffic is routed across the remaining good connection. To facilitate fast protocol rerouting, a test message is sent across the now active connection bound for the switch connected to the failed connection. This message therefor traverses both switches causing each to learn the new routing. Rerouting is therefor accomplished quickly.

Abstract: A valve position controller tuning method avoids impact of friction in valve positioner tuning by building a dynamic model of a valve positioner from a monotonic open-loop response of a valve stem position to a change in valve position controller output. To this end, a model form is selected based on the type of pneumatic actuator and relay that controls valve flow modulating of member motion, and the valve position controller is operated in an open-loop mode. The method includes changing a valve position controller output signal to cause the valve positioner to move a valve flow modulating member, connected to valve positioner, monotonically from one stuck position to another stuck position immediately after a motion in that same direction. When a valve stem position reaches a position threshold, a first valve stem position change and a corresponding time change are measured. The method includes measuring valve stem position changes at times that depend on the first measured time change.

Abstract: The present invention includes an electropneumatic positioner having an external binary input block which provides access to the electrical output of an integral electronic position controller to control operation of a valve relay. The invention enables manual control of the positioner for safety, maintenance etc.