Abstract: An industrial process control system includes a remote transmitter that measures a process variable to transmit data over a process control loop. A local databus interface includes an active current source and is configured to transmit and/or receive data on a local databus. The local databus includes a signaling wire operated to a high signal level during idle communications and modulated between the high and a low signal level during data communication. The active current source is coupled to the signaling wire of the databus to limit current drawn by the signaling wire during a low signal level.

Abstract: A scalable process transmitter architecture includes a unitized sensor module and an optional scalable transmitter. The sensor module has a sensor output that is configurable which can connect locally to a scalable transmitter module to form a transmitter, or can be wired directly to a remote receiver. The scalable transmitter can mount on the unitized sensor module and generates a scalable output for a remote receiver. The transmitter module can provide more advanced features for specific applications.

Abstract: A process variable transmitter connects a serial bus to an accessory load. A supply limiter circuit provides a first supply current limit and provides a stored energy output. A recessive driver circuit draws a drive current from the stored energy output and couples the drive current to the serial bus. The recessive driver circuit provides a drive current limit. A dominant driver circuit has a dominant state in which it conducts the drive current, and an inactive state in which the drive current is available to the accessory load.

Abstract: A modular process transmitter having a scalable EMI/RFI filtering architecture includes a unitized sensor module and a transmitter module. The unitized sensor module is adapted to operate as a stand-alone process transmitter. The transmitter module can couple to the unitized sensor module to expand the capabilities of the unitized sensor module. The unitized sensor module includes a sensor housing, a sensor circuit and a removable sensor EMI/RFI filtering circuit. The sensor circuit provides a sensor output in accordance with either a local format or a first communication protocol. The sensor EMI/RFI filtering circuit filters noise in accordance with the first communication protocol. The transmitter module includes a transmitter module housing, a communications circuit, and a transmitter module EMI/RFI filtering circuit.

Abstract: A scalable process transmitter architecture includes a unitized sensor module and an optional scalable transmitter. The sensor module has a sensor output that is configurable which can connect locally to a scalable transmitter module to form a transmitter, or can be wired directly to a remote receiver. The scalable transmitter can mount on the unitized sensor module and generates a scalable output for a remote receiver. The transmitter module can provide more advanced features for specific applications.

Abstract: Disclosed is a process control transmitter having an externally accessible DC circuit common that eliminates the need to perform level shifting of signals communicated between the transmitter and external processing electronics. The process control transmitter includes first, second and third terminals which feedthrough a housing. Circuitry contained in the housing is coupled to the first, second and third terminals and is adapted to communicate information to external processing electronics through the second and third terminals using a digital signal that is regulated relative to a DC common that is coupled to the second terminal. External processing electronics can couple to the second and third terminals and interpret the digital signal without having to perform level-shifting adjustments.

Abstract: A pressure sensor module and method for pre-installation without a converter module. The pressure sensor module is hermetically sealed and can remain undamaged in an installation environment without a converter module. The pressure sensor module can be assembled later with a converter module in the installation environment. The pressure sensor module includes an isolator, a pressure sensor and a circuit that provides a bus for energization, control and a digital pressure output. The bus is connected to contacts in an insulating feedthrough. An integrally formed hermetic external support structure surrounds the pressure sensor and circuit. The hermetic external support structure has a threaded process fluid inlet around the isolator, and a threaded support sleeve supporting the feedthrough.

Abstract: A sensor module has an outer module housing with an fluid inlet and a feedthrough with five electrical contacts. A transducer circuit in the module has a sensor connected to the inlet, a regulator connected to contacts 1, 2 and a transceiver providing a serial output to contact 3. A logic circuit is selectable to a first mode of operation in which the logic circuit generates ON-OFF logic levels on contacts 4, 5 or it can be selected to a second mode of operation in which the logic circuit detects ON-OFF logic levels on the contacts 4, 5.

Abstract: A scalable process transmitter architecture includes a unitized sensor module and an optional scalable transmitter. The sensor module has a sensor output that is configurable which can connect locally to a scalable transmitter module to form a transmitter, or can be wired directly to a remote receiver. The scalable transmitter can mount on the unitized sensor module and generates a scalable output for a remote receiver. The transmitter module can provide more advanced features for specific applications.

Abstract: A scalable process transmitter architecture includes a unitized sensor module and an optional scalable transmitter. The sensor module has a sensor output that is configurable which can connect locally to a scalable transmitter module to form a transmitter, or can be wired directly to a remote receiver. The scalable transmitter can mount on the unitized sensor module and generates a scalable output for a remote receiver. The transmitter module can provide more advanced features for specific applications.

Abstract: A process transmitter communications circuit has link terminals which are coupled to a process link, which supplies power to the circuit. A power source is coupled to one of the link terminals and is independent from the power supplied from the process link. Communications circuitry is coupled to the power source and link terminals, which transmits a transmitter signal over the process link, through the link terminals. A power sensing component is coupled to at least one of the link terminals and the communications circuitry and senses whether the power supplied by the process link is inadequate to transmit the transmitter signal. A power control component is coupled to the power source, the link terminals and the communications circuitry and selectively applies power from the power source to the communications circuitry for transmitting the transmitter signal when the power sensing component senses there is inadequate power supplied by the process link.

Abstract: A direct current (DC) powered process instrument start up circuit includes an energy storage device, a switching regulator circuit, a variable impedance circuit, and a voltage measurement circuit. The energy storage device is coupled between first and second power supply terminals. The switching regulator circuit is coupled to the energy storage device and has a regulated voltage output. The variable impedance circuit is coupled between the energy storage device and the first power supply terminal and has an impedance control input. The voltage measurement circuit has a measurement input coupled to the energy storage device and a measurement output coupled to the impedance control input.

Abstract: A level transmitter for use in a process application measures height of a product in a tank. The level transmitter includes a microwave antenna directed into the tank. A low power microwave source sends a microwave signal through the microwave antenna. A low power microwave receiver receives a reflected microwave signal. Measurement circuitry coupled to the source and receiver initiates transmitting of the microwave signal and determines product height based upon the received, reflected signal. Output circuitry coupled to a two-wire process control loop transmits information related to product height over the loop. Power supply circuitry in the level transmitter coupled to the two-wire process control loop receives power from the loop which powers the level transmitter including the microwave source and the microwave receiver.

Abstract: The invention comprises an additional zipper lock attachment. The zipper lock attachment is form of a spring steel rod with its ends overlapping one another in parallel flush engaged position. An intermediate portion of the steel rod has lateral bend.

Abstract: A jogging stroller includes a tricycle wheeled frame adapted for the installation of an existing vehicle child safety seat therein. Most such seats include clips which are attachable to a metal rod structure, as found in the typical grocery shopping cart, and the present stroller includes such structure providing for the rigid clipping of such seats to the stroller frame. Alternatively, the seats may be strapped to the frame if desired. Preferably, the frame structure is formed of steel tubing for strength and durability. The wheels are relatively large, preferably being of fifteen inch diameter, in order to provide for ease of movement over uneven terrain, and are quickly and easily removable without need for tools in order to provide for compact storage. The handles are foldable over the remainder of the structure when the seat is removed, for further compact storage. The handle grips are forwardly angled, for optimum ergonomics for a person pushing the stroller.

Abstract: The use of flexures in the form of flat spiral springs cut from sheet metal materials provides support for coaxial nonrotating linear reciprocating members in power conversion machinery, such as Stirling cycle engines or heat pumps. They permit operation with little or no rubbing contact or other wear mechanisms. The relatively movable members include one member having a hollow interior structure within which the flexures are located. The flexures permit limited axial movement between the interconnected members, but prevent adverse rotational movement and radial displacement from their desired coaxial positions.

Abstract: A protection circuit is provided for protecting sensitive electrical field instruments from a transient voltage strike and for ensuring that the instruments will meet safety approval during high potential voltage testing. The first and second wires of a two-wire circuit are connected to a first and second terminal respectively. A first surge arrestor electrically couples a first path between the first and second terminal. An impedance and a transient suppressor are connected in series and electrically couple a second path between the first and second terminal. The second path is coupled in parallel with the first path between the first and second terminal and is coupled closer to the internal components of the electrical instruments to be protected than is the first path. A second surge arrestor is electrically coupled between the second terminal and ground, and has a higher voltage breakdown potential than the first surge arrestor.

Abstract: An intestinal catheter is inserted into the gastrointestinal tract by use of an endoscope or a guidewire in combination with an inflatable bolus and performs the functions of aspirating the stomach and feeding the small intestine. The inflatable bolus may be filled with a heavy liquid such as water so that the downstream end of the catheter is moved through the gastrointestinal tract by peristalsis.

Abstract: A raisable hood plate mechanism for a vehicle hood comprises a pair of large plates laterally spaced in separate centered openings on opposite sides of the hood. The plates are pivotable along front edges and raisable at rear edges to provide rear-facing engine compartment ventilation, as well as glare deflection from the operator's eyes and bug and stone deflection from the windshield. The plate can be opened manually or by mechanical, fluid or electrical remote actuation mechanisms. An automatic closer can be employed. The plate can be light transmissive and solar collectors can be used with the plate.

Abstract: An interface unit is provided for transmitting signals to and receiving signals from several transmitters. The interface unit includes a DC power supply, an active load, and a transmit/receive circuit connected to the first wire of a two wire circuit which transmits signals to and receives signals from the transmitters. The active load is connected in series with the DC power supply between the first and second wire of the two wire circuit and has a first impedance at DC and a second, higher impedance within a frequency range defined by the signals transmitted to and received from the transmitters.