Abstract: A meter electronics (20) for generating a drive signal for a vibratory flowmeter (5) is provided according to an embodiment of the invention. The meter electronics includes an interface (201) and a processing system (203). The processing system is configured to receive the sensor signal (201) through the interface, phase-shift the sensor signal (210) substantially 90 degrees to create a phase-shifted sensor signal, determine a phase shift value from a frequency response of the vibratory flowmeter, and combine the phase shift value with the sensor signal (201) and the phase-shifted sensor signal in order to generate a drive signal phase (213). The processing system is further configured to determine a sensor signal amplitude (214) from the sensor signal (210) and the phase-shifted sensor signal, and generate a drive signal amplitude (215) based on the sensor signal amplitude (214), wherein the drive signal phase (213) is substantially identical to a sensor signal phase (212).

Abstract: A meter electronics (20) for generating a drive signal for a vibratory flowmeter (5) is provided according to an embodiment of the invention. The meter electronics includes an interface (201) and a processing system (203). The processing system is configured to receive the sensor signal (201) through the interface, phase-shift the sensor signal (210) substantially 90 degrees to create a phase-shifted sensor signal, determine a phase shift value from a frequency response of the vibratory flowmeter, and combine the phase shift value with the sensor signal (201) and the phase-shifted sensor signal in order to generate a drive signal phase (213). The processing system is further configured to determine a sensor signal amplitude (214) from the sensor signal (210) and the phase-shifted sensor signal, and generate a drive signal amplitude (215) based on the sensor signal amplitude (214), wherein the drive signal phase (213) is substantially identical to a sensor signal phase (212).

Abstract: A bus instrument (10) configured to predictively limit power consumption and adapted for use with a two-wire instrumentation bus is provided. The bus instrument (10) includes a sensor (13), a shunt regulator (14), and a controller (20). The controller (20) is configured to generate a predicted available power Ppredicted that will be available to the bus instrument (10) after a change in the loop current IL, compare the predicted available power Ppredicted to a present time power Pt0 comprising a controller power Pcontroller plus a sensor power Psensor, and reduce the sensor power Psensor if the total available power Pavailable is less than the controller power Pcontroller plus the sensor power Psensor.

Abstract: A method for executing a processing routine that utilizes an external memory is provided. The processing routine requires more than one external memory access. The method comprises the step of distributing the external memory access after a predetermined number of external memory accesses.

Abstract: A step-down voltage converter (100) for generating an output voltage (VOUT) from an input voltage (VIN) is provided. The converter (100) includes a switch (111) having a first terminal (112) and a second terminal (114), wherein the second terminal (114) is electrically coupled with the output voltage (VOUT). Also included is a rectifier (117) having a first terminal (118) and a second terminal (120), wherein the second terminal (120) is electrically coupled with the output voltage (VOUT). A first inductor (124) electrically couples the first terminal (112) of the switch (111) with the input voltage (VIN). A second inductor (126) magnetically coupled with the first inductor (124) electrically couples the first terminal (118) of the rectifier (117) with a voltage reference (128). A switch controller (110) coupled with the output voltage (VOUT) is configured to control the switch (111).

Abstract: An instrument power controller (120) for adaptively providing an output voltage VO and an output current IO that together maintain a substantially constant electrical output power PO is provided. The controller (120) includes inputs (121) for receiving an input power PI, outputs (122) for providing the substantially constant output power PO to a variable impedance load L, and a communication path (126) for receiving a load voltage VL. The instrument power controller (120) is configured to determine an input voltage VI and an input current II, determine an effective resistance RL of the load L and set the output voltage VO and the output current IO based on the input voltage VI, the input current II, and the effective resistance RL. The output voltage VO is substantially independent from the input voltage VI. The output voltage VO and the output current IO are varied to maximize a load power PL while maintaining the substantially constant electrical output power PO.

Abstract: A step-down voltage converter (100) for generating an output voltage (VOUT) from an input voltage (VIN) is provided. The converter (100) includes a switch (111) having a first terminal (112) and a second terminal (114), wherein the second terminal (114) is electrically coupled with the output voltage (VOUT). Also included is a rectifier (117) having a first terminal (118) and a second terminal (120), wherein the second terminal (120) is electrically coupled with the output voltage (VOUT). A first inductor (124) electrically couples the first terminal (112) of the switch (111) with the input voltage (VIN). A second inductor (126) magnetically coupled with the first inductor (124) electrically couples the first terminal (118) of the rectifier (117) with a voltage reference (128). A switch controller (110) coupled with the output voltage (VOUT) is configured to control the switch (111).

Abstract: A meter electronics (20) for generating a drive signal for a vibratory flowmeter (5) is provided according to an embodiment of the invention. The meter electronics includes an interface (201) and a processing system (203). The processing system is configured to receive the sensor signal (201) through the interface, phase-shift the sensor signal (210) substantially 90 degrees to create a phase-shifted sensor signal, determine a phase shift value from a frequency response of the vibratory flowmeter, and combine the phase shift value with the sensor signal (201) and the phase-shifted sensor signal in order to generate a drive signal phase (213). The processing system is further configured to determine a sensor signal amplitude (214) from the sensor signal (210) and the phase-shifted sensor signal, and generate a drive signal amplitude (215) based on the sensor signal amplitude (214), wherein the drive signal phase (213) is substantially identical to a sensor signal phase (212).

Abstract: A two-wire bus instrument (500) adapted for use with a two-wire bus (308) is provided according to an embodiment of the invention. An instrument element (304) receives a third current and generates one or more sensor measurement signals. A signal processor (512) receives a second current and processes the one or more sensor measurement signals to produce a data signal. A communication system (511) receives a first current, receives the data signal, generates a digital communication signal including the data signal, and modulates the digital communication signal onto a two-wire bus (308). A communication power supply (501) connected across the two-wire bus (308) provides the first current to the communication system (511). A signal processing power supply (502) connected across the two-wire bus (308) provides the second current to the signal processor (512). A drive current power supply (503) connected across the two-wire bus (308) provides the third current to the instrument element (304).

Abstract: A system for setting baud rate and communication protocol in a remote device. In this invention, the remote device receives samples of signals from a host device in a buffer. The remote device then detects a baud rate of said signals from the samples. A protocol being used by the host device to communicate is also determined from the samples. The remote device is then set to communicate using the determined protocol at the detected baud rate.

Abstract: A circuit for supplying a DC output of a desired voltage from an input regardless of power received. In this circuit, a rectifier converts an alternating current (AC) input to direct current (DC) or changes a DC input to a desired polarity. A boost converter receives DC current having a first voltage from the rectifier and outputs DC current having at least a minimal voltage. Finally, a buck boost converter receives the DC current having at least the minimal voltage and outputs DC having a desired voltage.

Abstract: Meter electronics for a Coriolis flowmeter capable of being intrinsically safe. A signal conditioner receives power from a power supply in a host system remote from the signal conditioner. Drive circuitry in the signal conditioner generates a drive signal and applies the drive signal to a driver affixed to at least one conduit of the Coriolis flowmeter. Pick-off signal conditioning circuitry in the signal conditioner receives input signals from a first pick-off sensor and a second pick-off sensor affixed to the at least one conduit of the Coriolis flowmeter, generates information indicating properties of a material flowing through the conduit from the input signals, and transmits output signals containing the information to the host system.

Abstract: To increase power to a measurement device, the measurement device measures a first voltage across the measurement device. The measurement device then determines an operating current based on the first voltage. The operating current is a maximum current that the measurement device draws without dropping a measurement device voltage below a threshold voltage to prevent resetting of the measurement device. The measurement device then generates a signal to change the power to use the operating current.

Abstract: The described circuit is an intrinsically safe circuit configured for supplying intrinsically safe power from a power supply in a hazardous environment. The intrinsically safe circuit reduces a number of node connections by reducing a number of components. The intrinsically safe circuit comprises an opto-coupler circuit configured for receiving a control signal, a resistor, and a single voltage limiting circuit. The reduction in components and node connections results in a reduction of board costs and area, while maintaining a desired level of protection.

Abstract: A circuit for supplying power to an intrinsically safe circuit having a power supply and output terminals includes an integrated current source feedback and current limiting element. Voltage limiting circuitry between the power supply and the output terminals limits the voltage across a load. Current limiting circuitry includes barrier resistors which convert current to voltage for input to an operational amplifier comparing a reference voltage with the voltage level representing the load current and providing a control input signal to a transistor for limiting a current applied to the load.

Abstract: An I/O signaling circuit having a single path through the circuit which can be configured to operate in one of a plurality of modes. A first circuit in the I/O signaling circuit adjusts the current flowing from a power supply to ground. A second circuit adjusts the voltage between a high potential terminal and low potential potential terminal through a remote secondary processing device. A processor determines the proper mode in which the circuit is to operate and then generates signals to adjust the first and second circuits to configure the circuit.

Abstract: Circuitry that provides alternating current to a load from a unipolar power supply. A current source in the circuitry controls current applied to the load. A first switch and a second switch are connected between the load and the current source and allow current to flow from the current source to the load in a first direction responsive to the first switch and the second switch being closed. A third switch and a fourth switch connected between the load and the current source allow current to flow from the current source to the load in a second direction responsive to the third switch and the fourth switch being closed.

Abstract: An adjustable charge pump design employs a variable voltage level means to reduce the charge on the charge pump charging capacitor. The charge pump output is thereby controlled without the use of any secondary pass elements applied to the charge pump output voltage. The variable voltage level means, e.g. a variable resistor, "steals" voltage from the charging capacitor in either an inverting charge pump configuration or a doubling configuration. The voltage converter employing the adjustable charge pump is advantageously applied to providing an adjustable contrast control for an LCD display. Certain intrinsic safety requirements are achievable with the present design thereby making possible a backlit, intrinsically safe LCD display.

Abstract: An opto-coupler comprising an LED and a photo-transistor whose collector resistor is connected in parallel with a diode comprising the emitter-base junction of a second transistor. This diode prevents saturation of the photo-transistor and at the same time, the current through the emitter-base junction diode of the second transistor is amplified by the gain of the second transistor to achieve and optimum signal output level across the collector resistor of the second transistor. The emitter-base junction diode of the second transistor prevents the photo-transistor from saturating and, in so doing, improves the rise and fall times of the collector current of the photo-transistor. The operation of the photo-transistor in a nonsaturation mode and the optimization of its rise and fall times for its collector currents result in an improvement in the data rate of the input signal that can be accommodated by the opto-coupler circuit.