Abstract: A system for determining the flow rate and temperature of air moving through a duct including a sampling or sensing head for sampling the air moving through the duct, a flow rate sensor connected to the sensing head for providing an output signal relating to the flow rate of air moving through the duct based upon the sampling of that air, and a temperature sensor connected to the sensing head for determining the temperature of the air moving through the duct based upon the sampling of the air moving through the duct.

Abstract: In a contention polling arrangement wherein polling messages are transmitted by a central controller for simultaneously polling a group of remote stations, the polling message contains an address which defines the entire range of remote stations to be polled and the remote stations will respond if their addresses fall between the address contained in the polling message and an address resulting from converting any trailing 0's of the address in the polling message to 1's.

Abstract: A method for producing sinusoidal waves uses the steps of generating a plurality of clock signals during a 2.pi. period, using the clock signals to control the generation of 2.pi. periodical square wave pulses having preselected length and phase relationships during respective ones of the clock signals and applying the square wave pulses to a low pass filter. The reduction of pulse length as well as the phase relationship of the pulses is evaluated from a system of equations by setting the odd harmonics of corresponding Fourier series to zero or to a predetermined minimum value. A circuit device utilizing this method uses a switching amplifier operated in a binary sequence having a period corresponding to the desired sine wave period and a low pass filter connected to the output of the amplifier.

Abstract: A system for determining the optimum stop time of an air conditioning system within a building so that energy can be conserved by shutting down the temperature control system an amount of lead time prior to end of occupancy of said building wherein said amount of lead time is arranged to confine space temperature within a comfort range as said space temperature drifts during said amount of lead time, said system including a space temperature sensor for sensing space temperature within the building, an outdoor air temperature sensor for sensing outdoor air temperature external to the building, and a controller connected to the space temperature sensor, the outdoor air temperature sensor and the temperature control system for determining temperature drift rate within the building and for turning off the temperature control system before the end of occupancy of the building by an amount of lead time dependent upon the temperature drift and the outdoor air temperature.

Abstract: A semiconductor junction related structure to control sensitivity of signal processing systems to signals of greater versus smaller values.

Abstract: An electromagnetic valve uses a solenoid coil to produce a magnetic attraction of a cylindrical shell core against the action of a spring. A valve seat is constituted by a plate of a hard material arranged to cooperate with a circular ridge on an end of the core to obtain an hermetic seal therebetween. The plate is maintained against a bearing surface within a valve housing by a telescoping element located within the shell core and providing a sliding support surface for the shell core.

Abstract: An explosion-proof type electro-displacement converter device comprising a cylindrical first yoke attached through a permanent magnet which is at the center of the bottom of a bowl-shaped second yoke, an exciter coil winding supported elastically by springs and arranged in the magnetic path formed between the yokes, the opening of the bowl-shaped yoke is sealed by a sealing means, and an output stem linked with the exciter coil winding and projecting, leaving an explosion-proof gap, through an opening which penetrates through the bowl-shaped yoke or the sealing means.

Abstract: A float stabilized constant current source uses a floated cylinder with a rotational signal output generator and two torque generators for applying a linear torque and an opposing current squared torque to the floated cylinder, respectively. The current squared torque is balanced against the linear torque by a servo system applying a current to the torque generators in series to create a point of zero net torque on the floated cylinder. The current is obtained from the signal generator representative of a cylinder rotation and is used as a stabilized constant output current, i.e., a precision constant current reference driving an electrical load.

Abstract: A fluid pressure regulating valve having a two-stage high and low flow rate control capability combined with a natural-LP gas control pressure changeover uses a spring biased pressure regulating diaphragm controlling a fluid through an orifice defined by a valve seat. A solenoid valve armature is attached to a spring providing the spring bias for the diaphragm and is arranged to be actuated by a selectively energizable solenoid coil. An extension of the armature is captured by a step regulator assembly which is threaded into a valve body containing the regulating diaphragm. The high fire and low fire adjustments in the step regulator assembly are on non-moving threaded members attached to the regulator assembly and bearing on the extension of the armature to vary the energized and deenergized position of the solenoid armature.

Abstract: A control system having combined closed loop and duty cycle functions uses a differential amplifier for amplifying the difference between a setpoint or reference temperature for a system to be controlled and a detected system temperature, a thermostat having a differential circuit for providing a predetermined hysteresis lag for an output of the amplifier and a duty cycle generating circuit for changing the operating potential of the differential circuit in accordance with a predetermined duty cycle to shift the operating point of the differential circuit.

Abstract: A communication apparatus for receiving both power and a sensor signal over the same transmission line having a first variable impedance element and a receiving impedance element connected in series across the transmission line, a second variable impedance element and a series impedance element connected in series across the transmission line, and a control circuit for controlling the first variable impedance element to maintain the transmission line voltage constant and for controlling the second variable impedance element to maintain the current flowing through the series impedance element constant, the control circuit simultaneously controlling the first and second variable impedance elements to maintain the current flowing through the series impedance element constant while transmitting data over the transmission line.

Abstract: A D.C. power control for a D.C. solenoid actuator which may be used for a D.C. solenoid operated valve uses a timer circuit for switching from an initial high pull-in power after a predetermined delay to a low hold power for the valve solenoid utilizing a pulse control where the valve "on" time is held constant and the "off" time is varied. The pulses are high frequency to prevent the valve from switching with each of the pulses while enabling the average current in the valve solenoid coil to be controlled independently between the pull-in and hold current values.

Abstract: An A.C. power control circuit for a D.C. solenoid actuator which may be used for a solenoid operated valve uses a triac circuit to initially apply A.C. line voltage to energize the solenoid coil of the valve to be actuated to provide valve pull-in power. A capacitor in an RC network is concurrently charged to a D.C. level, and the D.C. voltage on the capacitor is used to control the gate of the triac. After a predetermined delay as determined by the RC network charging time of the capacitor, the triac is phase controlled to produce a change in the current applied to the solenoid coil. In one embodiment, the voltage applied to the solenoid coil changes at this time from the full sine wave voltage of the A.C. source to a voltage pulse which is only a portion of the positive half of the input sine wave. This voltage produces a change in the power applied to the solenoid coil to a hold-in power level. This circuit produces a current pulse phase control of up to 90.degree..

Abstract: In a variable time division distributed bus control system for determining the order in which a plurality of stations can communicate messages over a common communication channel, the system includes a communication channel for transmitting information between a plurality of stations, each station having a time slot memory for storing at least one address identifiable as a time slot during which an assigned station can transmit information over the communication channel, each time slot having only one station assigned thereto, and a transmission controller responsive to the messages being transmitted over the communication channel and responsive to the time slot memory for transmitting messages over the communication channel when it is the turn of each station to transmit.

Abstract: A two-stage solenoid valve uses a pair of stacked coaxial armatures in a cylindrical sleeve housing. A first armature is provided with a fluid sealing ring and is urged by a first spring to peripherally seal an adjacent internal fluid port in a valve base supporting a first end of the sleeve housing. The first armature is provided with a coaxial bore extending through the armature and coaxial with the fluid sealing ring to form a fluid channel. The second armature also has a coaxial bore extending therethrough with a resilient sealing member slideably retained within the bore. A second spring is arranged to urge the resilient sealing member against a first end of the bore in the second armature and to extend therefrom to a fixed plug in a second end of the cylindrical housing. The resilient sealing member cooperates with a fluid port defining an end of the coaxial bore in the first armature opposite the end of the first armature having the fluid sealing surface.

Abstract: A receiving apparatus for receiving an electrical signal over a 2-wire transmission line, the electrical signal having a signal component and a bias component, the bias component being used by the receiving apparatus for providing power to the receiving apparatus, the receiving apparatus having a first variable impedance element and a receiving impedance element connected in series across the transmission line, a second variable impedance element and a series impedance element connected in series across the transmission line, and a control circuit for controlling the first variable impedance element to stabilize the voltage across the transmission line to a constant value and for controlling the second variable impedance element to stabilize the current flowing through the series impedance element to a constant value, so that a current flowing through the receiving impedance element relates to the signal component and the current flowing through the series impedance element relates to the bias component.

Abstract: An alarm message generation and broadcast system having supervision including an alarm message generation circuit for generating an alarm message, an output for receiving the alarm message so that the alarm message can be broadcast in response to an alarm event; and a supervision circuit connected to the alarm message generation circuit and responsive to the alarm message for providing a trouble signal when the alarm message is not properly received by the supervision circuit.

Abstract: An adaptive control system uses a controller for controlling an air temperature treatment apparatus at a reduced energy consuming level during periods of non-occupancy of a building and for energizing the air treatment apparatus before occupancy so that a desired internal building temperature is reached by a time of occupancy.