Abstract: A thermostat having a temporary "now" and "next" functions. The temporary "next" function allows the user to program a temporary deviation from a preprogrammed schedule used to control the temperature within a space. The combination temporary "now" and "next" function allows a user to temporarily set a current setpoint which will be held until a temporary next setpoint becomes the control setpoint, after which the thermostat returns to the preprogrammed setpoints.

Abstract: A security system in which sensors are included in one or more groups which are stored in the system. Groups of sensors are selectably actuable by a user entering mode information into the system so that only the selected group(s) will provide indication of an alarm condition when a sensor indicates an alarm event has occurred.

Abstract: A structure is formed from two layers of material having opposite conductivity types. A first region is formed within the structure, and extends at least in part into a layer to be etched. A surface of the structure is then masked and etched. The result is a microstructure which varies with the conductivity type and geometry of the region formed and etchant used.

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

Abstract: A thermostat providing external communication comprising two microprocessors. One microprocessor may be dedicated to the external communication while the other microprocessor runs the application programming. The thermostat is separated into a thermostat housing and subbase. One microprocessor may be located within the thermostat housing with the other located within the subbase. This allows for changing the applications programming through replacement either the housing or the subbase. Replacement of only one portion of the thermostat is cheaper and can be easier.

Abstract: A thermostat which includes a transceiver for receiving and sending communications externally of the thermostat. A thermostat receiving external communications from another thermostat includes an external temperature responsive portion to modify the setpoint of the receiving thermostat based on the information received by the receiving thermostat.

Abstract: A structure and method of making a piezoresistive transducer with reduced offset current. The transducer is comprised of a piezoresistive die having a support rim and a diaphragm, and a support housing having a wall and an aperture. The shape of the diaphragm is matched with the shape of the aperture while the shape of the support rim is matched with the shape of the wall. By matching these shapes, temperature induced stresses are reduced, thus reducing temperature induced offset currents.

Abstract: A system for controlling the operation of an HVAC system which includes a direct expansion coil, a condenser, a pre-cool coil, and a control system. The control system includes a controller and sensors. The controller receives signals indicative of air flow through the direct expansion coil from the sensors, compares the received signal to a stored air flow rate, and disables the compressor if the stored air flow rate is equal to or greater than the stored value. The controller is also adapted to vary air flow into an occupied space for small changes in the cooling load. In addition, the controller can artificially load the compressor during periods of small cooling load by restricting flow of a cooling agent between the cooling tower and the condenser, or by directing warm water from the condenser through the pre-coil coil.

Abstract: A system for controlling the operation of an HVAC system which includes a direct expansion coil, a condenser, a pre-cool coil, and a control system. The control system includes a controller and sensors. The controller receives signals indicative of air flow through the direct expansion coil from the sensors, compares the received signal to a stored air flow rate, and disables the compressor if the stored air flow rate is equal to or greater than the stored value. The controller is also adapted to vary air flow into an occupied space for small changes in the cooling load. In addition, the controller can artificially load the compressor during periods of small cooling load by restricting flow of a cooling agent between the cooling tower and the condenser, or by directing warm water from the condenser through the pre-coil coil.

Abstract: A pressure transducer having means for improving the linearity and sensitivity of an output signal from the pressure transducer. Ribs and bosses are introduced in the diaphragm region to collect the moments caused by a difference in pressure on the two sides of the diaphragm and thus improve device sensitivity. In addition, the ribs and bosses prevent stretching of the piezoresistors thus improving the linearity of the device. A constraint can also be included to improve the alignment of the piezoresistors thus improving the linearity of the device.

Abstract: In a wireless alarm system an arrangement for increasing the reliability that messages will be received is provided. Each transmitter transmits an alarm message a plurality of times with delays between the messages. Successive delay times are of different duration to increase the likelihood that messages will not be lost if two transmitters transmit at the same time.

Abstract: A low voltage monitor and microcontroller output monitoring circuit for insuring proper operation of a microcontroller in a furnace control system. A switch connected to a reset port of the microcontroller is capable of putting either a high or low voltage signal at the reset port. A high signal is required for normal operation of the microcontroller. The low voltage monitor connects to a power supply providing power to the microcontroller and causes the switch to provide a low signal to the reset port if the output voltage of the power supply drops below a predetermined level. The output monitoring circuit insures that the microcontroller is operating properly by insuring that the microcontroller is producing an output signal at a predetermined frequency and repetition rate. If the output signal is not at the predetermined frequency, the output monitoring circuit causes a low voltage to be present at the reset port.

Abstract: A thermostat having a simple to see and use setup-setback visual indicator. One temperature control is used to set temperature while a second temperature control is used to activate the setup or setback. The second temperature control is offset from the body of the thermostat in the setup or setback mode to provide simple visual indication of the setup or setback.

Abstract: A system for controlling the operation of an HVAC system which includes a direct expansion coil, a condenser, a pre-cool coil, and a control system. The control system includes a controller and sensors. The controller receives signals indicative of air flow through the direct expansion coil from the sensors, compares the received signal to a stored air flow rate, and disables the compressor if the stored air flow rate is equal to or greater than the stored value. The controller is also adapted to vary air flow into an occupied space for small changes in the cooling load. In addition, the controller can artificially load the compressor during periods of small cooling load by restricting flow of a cooling agent between the cooling tower and the condenser, or by directing warm water from the condenser through the pre-coil coil.

Abstract: A control device for a radiator valve comprises a housing (10, 12) including an operating, display, control and power supply portion, (14, 16, 18). Said housing comprises a cut-out (24) with which it is slipped-over a motorized drive unit (30-84). When the housing (10, 12) is removed from the drive unit, a reception housing (38) for a motor (34) and a gear unit (36) can be rotated as a hand wheel with respect to a stationary drive housing (32) flanged to the radiator valve so that the valve may be manually operated. A ring (66) being rotatable with respect to the reception housing (38) and a drive housing (32) allows balancing of tolerances and matching to radiator valves of different manufacturers.

Abstract: A system for controlling the operation of an HVAC system which includes a direct expansion coil, a condenser, a pre-cool coil, and a control system. The control system includes a controller and sensors. The controller receives signals indicative of air flow through the direct expansion coil from the sensors, compares the received signal to a stored air flow rate, and disables the compressor if the stored air flow rate is equal to or greater than the stored value. The controller is also adapted to vary air flow into an occupied space for small changes in the cooling load. In addition, the controller can artificially load the compressor during periods of small cooling load by restricting flow of a cooling agent between the cooling tower and the condenser, or by directing warm water from the condenser through the pre-coil coil.

Abstract: In order to distinguish useful electrical signals from noise signals which are superimposed on the useful signals, a time window is moved along the receiver signal by means of a shift register. If within this time window the received signal exceeds a predetermined minimum level for a predetermined period of time, this receiver signal is recognized as being a useful signal.

Abstract: A system for controlling the operation of an HVAC system which includes a direct expansion coil, a condenser, a pre-cool coil, and a control system. The control system includes a controller and sensors. The controller receives signals indicative of air flow through the direct expansion coil from the sensors, compares the received signal to a stored air flow rate, and disables the compressor if the stored air flow rate is equal to or greater than the stored value. The controller is also adapted to vary air flow into an occupied space for small changes in the cooling load. In addition, the controller can artificially load the compressor during periods of small cooling load by restricting flow of a cooling agent between the cooling tower and the condenser, or by directing warm water from the condenser through the pre-coil coil.

Abstract: A gas valve control system including a microprocessor, a first relay, a second relay, flame sensor and a timer. The timer is connected to the switch which is connected in the power supply path of the second relay. The second relay is connected to the valve. Activation of the first relay causes activation of the second relay causing the valve to open. Also, activation of the first relay causes the timer to operate. The flame sensors then must sense flame or else the microprocessor will deactivate the first relay. If the microprocessor fails to deactivate the first relay, the timer causes the switch to open and break the power supply path to the second relay. This in turn causes the valve to close.

Abstract: A system and method for delineating the edges of an object in an image frame formed of a two dimensional array of pixels represented by a plurality of gray scale values representing the gray scales of the pixels. A reference contrast level based on the distribution of contrast levels between contiguous pixels is established, and the contrast levels of pairs of pixels in square groupings of four contigous pixels are compared with the reference contrast level. A two dimensional array of elements corresponding to the arrangement of the square groupings of pixels is formed in which each element has a first value only if the contrast level between a pair of pixels in a square grouping is greater than the reference contrast level.