Abstract:
The present invention is a technique for forming a digital signal representing an environmental condition. The technique consists of measuring the variable time constant of an analog sensing device having a variable resistance dependent upon the environmental condition and a capacitor as well as measuring the reference time constant of a precision fixed resistor and the same capacitor. The time constants are measured by discharging the capacitor, charging the capacitor through the appropriate element and measuring the time for the voltage across the capacitor to reach a predetermined level. Lastly, the digital ratio between the two time constants is formed. This digital ratio is the digital representation of the environmental condition sensed by said analog sensing device.
Abstract:
The present invention is a technique for thermostatic control of a temperature modifying apparatus such as a heating unit or an air conditioning unit. This technique involves measuring the ambient temperature, generating an error signal based upon the difference between a set point temperature and the measured ambient temperature, operating the temperature modifying apparatus according to the error signal, and adjusting the set point temperature based upon the time history of the error signal. In accordance with the preferred embodiment of the present invention, the temperature modifying apparatus is operated during the next cycle interval with a duty cycle proportional to the error signal at the start of the cycle interval. In the preferred embodiment the set point is adjusted via an adjustment quantity which is increased if the new duty cycle factor is greater than the previous duty cycle factor, decreased if the new duty cycle factor is less than the previous duty cycle factor and maintained unchanged if the new duty cycle factor equals the previous duty cycle factor, with the adjustment quantity maintained within a predetermined band.
Abstract:
The present invention is a technique for thermostatic control of a temperature modifying apparatus such as a heating unit or an air conditioning unit. This technique involves measuring the ambient temperature, generating an error signal based upon the difference between a set point temperature and the measured ambient temperature, operating the temperature modifying apparatus according to the error signal, and adjusting the set point temperature based upon the time history of the error signal. In accordance with the preferred embodiment of the present invention, the temperature modifying apparatus is operated during the next cycle interval with a duty cycle proportional to the error signal at the start of the cycle interval. In the preferred embodiment the set point is adjusted via an adjustment quantity which is increased if the difference between a desired temperature is of one sense decreased if the difference is of the opposite sense and maintained unchanged if the desired temperature equals the measured temperature, with the adjustment quantity maintained within a predetermined band.
Abstract:
An electronic de-icing thermostat adapted to be connected to an air-cooling apparatus, such as an air conditioner, to control its state of operation. The thermostat includes means for generating a digital electrical signal representative of a desired temperature setpoint, means for measuring the ambient temperature of the thermostat and means for generating control signals for deenergizing the compressor in the air-cooling apparatus for a first preselected period of time whenever the compressor is determined to have run continuously for a second preselected period of time in order to inhibit the accumulation of ice on the cooling element of the air-cooling apparatus. The device preferably includes means for adaptively adjusting the length of the second and/or first preselected periods of time as a function of the change in the rate of change of the ambient temperature measured during the operation of the air-cooling apparatus.
Abstract:
A programmable thermostat employing means for sensing the ambient temperature on the thermostat, a clock for generating digital electrical signals representative of real time, a programmable digital memory for retaining a schedule of times and temperature ranges for a particular repetitive time cycle, display means for indicating selected information including programming mode, time, and temperature conditions during the programming and operation of the device, and control means for interrogating the current temperature range in the times-temperatures schedule, determining whether the ambient temperature on the thermostat is within that range, and generating a control signal to the furnace or air conditioner when appropriate.
Abstract:
An electronic multiple-setback thermostat for residential and commercial use includes an internal clock having a week-long cycle. The thermostat is programmed by the operator, usually manually actuable input devices, to control the furnace/air conditioning system to achieve a schedule of temperatures over the weekly period by simply inputting the temperature desired to be attained at the time of entry. Each temperature entry may be programmed to reoccur on a daily basis or to modify the program on a once-a-week basis. The thermostat employs an internal clock which controls memory addresses so that each memory location is representative of a short time period during the weekly cycle. A desired temperature signal is entered in a memory location determined by the clock state at the time of entry and is read out to the control system each time that time state reoccurs. The external temperature sensor employs a thermistor controlled oscillator that is used as the system clock source during failures of the primary power source.
Abstract:
An electronic multiple-setback thermostat for residential and commercial use includes an internal clock having a week-long cycle. The thermostat is programmed by the operator, usually manually actuable input devices, to control the furnace/air conditioning system to achieve a schedule of temperatures over the weekly period by simply inputting the temperature desired to be attained at the time of entry. Each temperature entry may be programmed to reoccur on a daily basis or to modify the program on a once-a-week basis. The thermostat employs an internal clock which controls memory addresses so that each memory location is representative of a short time period during the weekly cycle. A desired temperature signal is entered in a memory location determined by the clock state at the time of entry and is read out to the control system each time that time state reoccurs.The external temperature sensor employs a thermistor controlled oscillator that is used as the system clock source during failures of the primary power source.
Abstract:
An electronic multiple-setback thermostat for residential and commercial use includes an internal clock having a week-long cycle. The thermostat is programmed by the operator, usually manually actuable input devices, to control the furnace/air conditioning system to achieve a schedule of temperatures over the weekly period by simply inputting the temperature desired to be attained at the time of entry. Each temperature entry may be programmed to reoccur on a daily basis or to modify the program on a once-a-week basis. The thermostat employs an internal clock which controls memory addresses so that each memory location is representative of a short time period during the weekly cycle. A desired temperature signal is entered in a memory location determined by the clock state at the time of entry and is read out to the control system each time that time state reoccurs. The external temperature sensor employs a thermistor controlled oscillator that is used as the system clock source during failures of the primary power source.