Honeywell G.m.b.h.

Honeywell International Inc.

John T Adams

Rolf Lee Strand

John E Bohan, Jr

Timothy M Tinsley

T Michael Tinsley

Steven C Nichols

Arlon D Kompelien

Marvin D Nelson

Sybrandus B V Munsterhuis

Bruce L Hill

Ulrich Bonne

Cleopatra Cabuz

Brent Chian

Eugen I Cabuz

Timothy J Nordberg

Edward L Schwarz

Peter M Anderson

Tzu-Yu Wang

Kenneth B Kidder

Dale A Mueller

Richard W Simons

B Hubert Pinckaers

Stephen J Kemp

Gerrit Jan Baarda

Jeffrey R Meyer

Arthur J Punyko

Phyllis L Brown

A low-cost, two-wire, half-duplex high speed powered communications bus having a master/controller and one or more slave/sensor/interface units. The master/controller may have a current-limited power supply, and receive/transmit circuitry. Each slave/sensor/interface may have polarity protection and also have receive/transmit circuitry. The power supply may provide high/low voltage levels on the bus and over-current protection, and have one or more diodes for mis-wire protection. Each transmit circuit may have a tunable R-C network for limiting RF emissions. Each slave/sensor/interface may receive data and power over the two-wire bus.

Two-wire communications bus system

A system for adjusting a bias voltage of a flame sensing system. The system may use pulse width modulation to adjust the bias voltage. The system may have a flame sensing rod that conveys an electrical equivalent circuit of a flame presence to a detector via low pass filter. An excitation voltage may be conveyed via a DC blocking mechanism to the sensing rod. A pulse width modulation signal may be conveyed via a bias resistor to a node of the low pass filter and the detector. The input of an A/D converter may be that of the detector for flame signals. Also, leakages between the node of the A/D converter connection and the voltage source and/or ground may be detected and compensated. Further, leakage of the DC blocking mechanism may be minimized.

Dynamic DC biasing and leakage compensation

A gas valve body with a first flow chamber and, a second flow chamber including and a main valve positioned in line and between the first flow chamber and the second flow chamber. The main valve can be opened by creating a pressure differential across the main valve. An electrostatically controlled pilot valve is provided for controlling the pressure differential across the main valve for 'on-ff' operation. The electrostatically controlled pilot valve may also be operated to 'modulate' the pressure differential across the main valve along a range of pressure differential values.

Electrostatically actuated gas valve

A water heater control system that prevents the accumulation and accidental ignition of dangerous quantities of unwanted flammable vapors. The system intermittently generates a spark at a predetermined interval such that if unwanted flammable vapors are present, they are burned in a controlled manner. The system obviates the need for flammable vapor sensors.

Sensorless flammable vapor protection and method

A controller area network (CAN) has a plurality of nodes connected to transmit and receive data over a serial data line using an interface circuit to connect the node to the data line. Each interface circuit includes an isolation element, typically a diode, to connect the interface circuit to the data line. An indicator element in the interface circuit is powered when the node is transmitting. The isolation element in each node prevents other nodes while transmitting, from powering the indicator element in its node.

Status indicator for an interface circuit for a multi-node serial communication system

A controller area network (CAN) has a plurality of nodes connected to transmit and receive data over a serial data line. An AC power source is also connected to each node. Each node senses the AC power waveform and synchronizes bit transmission and bit detection with the waveform. In a preferred embodiment, each node includes a circuit that detects zero crossings by the AC waveform, providing two accurately synchronized bit intervals per complete AC cycle. A preferred version of the invention includes hardware and software that detects miswires of the node to the data and power lines.

AC synchronization with miswire detection for a multi-node serial communication system

A solid-state fail safe gas valve system in which first and second gas valves are arranged in series in a gas passageway, the valves being actuatable by first and second solenoid operators respectively, the second operator requiring a voltage greater than the operating voltage supplied to the valve system to achieve actuation. The operators are separately energized through microprocessor controlled switches so that a capacitor connected across the second operator and its switch is pumped to a voltage above the supplied voltage by voltage induced by interrupted energization of the first operator.

Fail-safe gas valve system with solid-state drive circuit

A flame rectification type flame sensor circuit and method in which a generator injects periodic pulses of alternating voltage into a flame region, the voltage across the flame region being processed by a filter/amplifier which, in proper operation, produces a non-zero output signal only during the time a flame is present and a pulse of alternating voltage is being supplied by the generator. Final indication of a flame is produced only if a non-zero output signal occurs during the time a pulse of alternating voltage is being supplied, and not during the time between successive pulses of alternating voltage. Failure of an electrical component in the filter/amplifier is indicated if a non-zero output signal occurs during the time between successive pulses of alternating voltage.

Flame rectification sensor employing pulsed excitation

An interface circuit is designed to connect a first logic circuit such as a microcontroller with a second similar microcontroller using three wires and allowing for simultaneous transfer of data from each of the microcontrollers to the other. A transmitter element in each interface circuit has a bias resistor which cooperates with a pull-up resistor in the other interface circuit to provide an indication for one of the logic circuits when the other of the logic circuits and its associated interface circuit loses power or when one of the three connecting wires is disconnected.

Connected processing systems including mutual power off and signal path

A method and apparatus provide input protection in a system having a controller which monitors a controller terminal for at least one monitor period. The controller terminal is coupled for bi-directional operation. The controller terminal is set to an output configuration for at least a portion of the time that the controller terminal is not being monitored by the controller.

Microcontroller controlled input protection

An apparatus and method for providing a microprocessor having an inaccurate oscillator with a desired time base. The cycles of the output signal of the oscillator are counted by a first counter until the counted number equals a predetermined correction count. The first counter then produces a timing signal. A second counter is set up to create an actual count indicative of the number of output signals occurring during a predetermined number of periods of an AC signal generator connected to the microprocessor. A predetermined desired count is then subtracted from the actual count to produce a difference count. The difference count is then added to the old correction count to create a new correction count. By iterating this process until the difference count is equal to zero, the timing signal is modified until it is equal to the desired time base.

Self correcting time base for inaccurate oscillators

A recovery algorithm for a setback thermostat uses the intersection of the space temperature with a sloped recovery temperature line which approximates the change in temperature as a function of time during recovery of the temperature controlled space from a setback temperature, to determine the time at which recovery to the occupancy temperature should begin. The thermostat starts recovery when the current space temperature crosses the recovery temperature line. A useful feature of the apparatus and method which implement the invention, computes and constantly updates the slope of the recovery temperature line. The update of the recovery temperature line slope is based on miss time, i.e., the time between actually achieving the desired next set point temperature and the next set point time associated with the next set point temperature. If the heating or cooling load on the space changes, the recovery temperature will frequently cross the recovery temperature line at a different time, causing recovery to start at a time more compatible with the current heating or cooling load in order to complete recovery at or near the desired time.

Self-adjusting recovery algorithm for a microprocessor-controlled

Low cost temperature sensor for thermostats utilizing a calibration resistor and a microprocessor with switchable ports wherein said microprocessor selects between high impedance input or an output for a temperature sensing element and a calibration resistor where by selecting the input, the temperature sensing element or the calibration resistor are effectively removed from the circuit thus allowing the low cost temperature sensor to self calibrate itself.

Low cost calibration system for frequency varying temperature sensing

A thermostat having a simple battery level detection circuit. The output of an oscillator, having a frequency dependent upon the battery level, is compared to the output of a battery level independent time base. If the two outputs are not in a predetermined relationship, all connected HVAC equipment is shut off.

Thermostat having simple battery level detection

A process of operating an electronic thermostat so that it models the effects of a mechanical thermostat anticipator.

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Minneapolis, MN, United States of America

John T Adams