Abstract: An electromagnetic flowmeter having a single bobbin coil for developing a magnetic field through which a liquid passes. The single bobbin coil is a part of an electromagnet unit which also includes first and second pole pieces which are disposed symmetrically about the channel through which the liquid passes. The pole pieces are focused toward the liquid flow channel to develop a uniform magnetic field which extends through the channel.

Abstract: A dual processor computer system with error checking that stops immediately when a discrepancy is detected between the two processors. The system includes a first processor for executing a series of instructions including input/output instructions. A second processor executes the same instructions independently of and in synchronization with the first processor. Both processors have a processor independent bus interface. All significant processor address, data, and control signals are connected to all peripheral devices by a processor independent I/O bus. A comparison circuit detects discrepancies in the operation of the two lock step processors and provides a signal that immediately stops operation of the processors when an error is detected. Each processor is connected through its associated processor independent bus interface to the comparison circuit and the first processor is also connected through its interface to the I/O bus.

Abstract: A magnetoinductive flow meter with a measuring tube, an electromagnet device with at least one electric conductor loop arrangement for generating a magnetic field penetrating the measuring tube at right angles to the longitudinal axis thereof, and at least two measuring electrodes, which are arranged opposite one another at right angles to the longitudinal axis of the measuring tube in such a way that they can be used to tap a measuring voltage induced owing to the flow, proceeding at right angles to the magnetic field, of a liquid flowing through the measuring tube. The electric conductor loop arrangement has an electrically conductive sheet-metal part which is fitted on the inner side or on the outer side of the body of the measuring tube and is provided with at least one cutout as inner boundary of the conductor loop current path running around the cutout in the sheet-metal material.

Abstract: An electromagnetic flowmeter comprising a body having a central channel having a measuring region, an inlet region and an outlet region. Relative to liquid flow through the central channel, the inlet region is upstream of the measuring region, and the outlet region is downstream of the measuring region. The inlet region and outlet region have diameters substantially greater than the diameter of the measuring region. A transition region extends between the inlet region and the measuring region, and a transition region extends between the measuring region and the outlet region. First and second cavities are respectively positioned in the inlet region and the outlet region, and third and fourth diametrically opposed cavities extend from the measuring region of the central channel. First and second grounding electrodes are respectively positioned in the first and second cavities, and third and fourth measuring electrodes are respectively positioned in the third and fourth cavities.

Abstract: A FSK modulator which uses the combination of a state machine and a toggle flip-flop to generate the FSK signals. The state machine has a loop having a predetermined number of states. The number of clock cycles that the state machine takes to traverse the loop depends on the state or level of the signal at the input to the modulator. The flip-flop converts the state machine output signal to a signal having a rectangular waveform.

Abstract: A method and apparatus for notifying a receiving device of fault conditions in a sensing element or an instrument. The instrument generates an analog signal that has an amplitude which is representative of a variable. The analog signal amplitude has a range defined by a lower limit and an upper limit. The instrument transmits the analog signal to the receiving device. When the instrument detects a fault condition in itself or in the sensing element, the transmitter periodically changes the analog signal amplitude by a predetermined amplitude for as long as the fault condition exists. The predetermined amplitude and its polarity are such that the amplitude of the periodically changed analog signal lies within the range. The receiving device generates an alarm when it detects the pulses.

Abstract: An electrochemical sensor wherein an ion impermeable plug is interposed between the adjacent faces of the large plugs that are used in the salt bridge. The salt bridge also includes a solid cylindrical plug that passes through the ion impermeable plug to thereby interconnect the adjacent large plugs. The large plugs have a central bore for receiving the glass sense electrode. The impermeable plug has protrusions to provide a better seal between the impermeable plug and the glass sense electrode and the impermeable plug and the housing in which the salt bridge is inserted. In addition, the sensor may also include a rigid liner between the large plugs and the glass sense electrode to act as a barrier to prevent damage to this sense electrode during and after impregnation.

Abstract: A computer keyboard retaining assembly having a removable peg mounted to the bottom of the keyboard and being insertable into a spring loaded peg holder mounted flush with a workstation work surface to allow rotational and lateral movement of the keyboard along the surface to optimally orient the keyboard with respect to the workstation operator while preventing the accidental dropping of the keyboard off the Workstation surface.

Abstract: A method and apparatus for calculating a ratio, R, having a first capacitance value, C.sub.1, in inverse relation to a second capacitance value, C.sub.2, where C.sub.1 and C.sub.2 are the capacitance values of a first capacitor and a second capacitor respectively. The first and second capacitors each have an independent electrode and share a common electrode. An AC voltage is applied to the common electrode producing first and second AC current signals at the two independent electrodes. A dual switched-capacitor integrated circuit and two current to frequency converters respectively convert the first and second AC current signals to first and second frequency signals having values f.sub.1 and f.sub.2. A microprocessor receives the first and second frequency signals and calculates R from f.sub.1 and f.sub.2.

Abstract: A position control circuit having a demodulator with automatic tuning capability for use in an electro-hydraulic positioning system used to position a servo device. The position control circuit includes the demodulator, an analog to digital converter with an input voltage range, and a microcontroller. The demodulator has a gain and is operable to convert a feedback signal from the servo device to a position signal having a lower voltage value when the servo device is at its 0% position and an upper voltage value when the servo device is at its 100% position; the lower voltage value and upper voltage values being a function of the demodulator gain.

Abstract: Digital supervisory and diagnostic circuitry to provide a watchdog function and a low voltage detect function and diagnostics for those functions. The watchdog function has a high immunity to EMI and RFI disturbances and may be enabled or disabled as necessary. An indication is provided of the cause of the last reset so that a reset due to EMI can be distinguished from a reset due to a power failure. The low voltage detect circuitry is implementable in an integrated circuit chip. The low voltage detect circuitry eliminates oscillations from the reset signal and provides a delay which is programmable by the user. The circuitry is designed so that the length of the delay can never be zero.

Abstract: A wing station is mounted proximately to a computer monitor to allow simultaneous viewing of both the wing station and the computer monitor by the operator. The wing station includes a liquid crystal display and an annunciator unit with a control panel.

Abstract: A self diagnostic system for a flame detector. The system produces an optical determinant signal from an analog determinant signal that has a controllable amplitude and frequency. The system detects the optical determinant signal and the optical signal from the flame and processes both signals to thereby continuously monitor the flame while also continuously analyzing the operating status of the flame detector.

Abstract: A computer floppy drive mounting assembly is made to be slidably removable from a slide casing assembly located proximately to an open slot on the front of the computer without the use of any by allowing the drive mounting assembly to have a slotted portion near the front which fits over the edge of the open slot to hold the floppy drive in the computer and which when lifted over the edge allows easy removal of the floppy drive to provide easy access to the computer fuses inside the computer to allow them to be serviced and or replaced by the computer operator.

Abstract: A method and apparatus for increasing the resolution of a pulse width modulated signal representative of a measured parameter such as the pressure measured by a pressure cell. The analog signal from the pressure cell is converted to a digital signal using a predetermined clock frequency. The digital signal is scaled to 2.sup.N (N is an integer greater than or equal to one) times the clock frequency and the N lowest order bits are checked to determine if they are a one or a zero. A one is added to the least significant bit of the scaled digital signal in a predetermined manner in the next N consecutive cycles of the scaled digital signal dependent upon the which of the N lowest order bits are a one.