Electronic thermostat

• US RE32,960 E
• Filed: 09/26/1985
• Issued: 06/20/1989
• Est. Priority Date: 03/17/1977
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Levine, Michael R.
• Primary Examiner(s): Gruber, Felix D.
• Application Number:
  US06/780,412
• Time in Patent Office: 1,363 Days
• Field of Search: 364/505, 364/418, 364/143, 364/144, 364/557, 236/46 R, 236/68 B, 236/DIG. 8, 165/12, 165/22, 165/26, 340/309.15, 219/492, 62/157, 62/231
• US Class Current: 700/278
• CPC Class Codes: G05D 23/1917 using digital means
• CPC Class Codes: G05D 23/24 the sensing element having a resistance varying with temperature, e.g. a thermistor

Abstract

A thermostat for generating control signals for a furnace, air conditioner, or the like, employs a constant frequency, periodically alternating electrical source and an oscillator incorporating an element having a thermal-sensitive electrical characteristic so the oscillator frequency varies as a function of the ambient temperature. A comparator receives the two outputs and generates a signal representative of the ambient temperature. The stable output is also provided to dividing circuits to generate a signal representative of the time that is used to interrogate a digtal memory storing a desired temperature-time period, such as a week or month. The ambient temperature signal is compared with the desired temperature signal to generate an output control signals. A display provides a read-out of time and temperature and is used along with a keyboard or the like in programming the memory.

Claims

1. digital time generating means..]. .Iadd.18. A thermostat for controlling the application of electrical power to a specified electrically controlled temperature modifying device comprising:

a source of a periodically alternating electrical signal whose frequency is constant at ambient temperatures over the range of the thermostat;

a source of a periodically alternating electrical signal whose frequency varies as a function of the ambient temperature on the thermostat;

circuit means, responsive to the respective frequencies of said time-base electrical signal and said temperature-sensitive electrical signal, for generating a digital electrical signal representing the ambient temperature on the thermostat;

a clock utilizing an output from said source of a constant frequency electrical signal to generate digital electrical signals having values representative of real time;

a programmable, digital memory;

means for loading said memory with a plurality of separate programs for alternative use in controlling the specified temperature modifying device, each said program comprising digital signals representing desired temperatures at particular times over a twenty-four hour period;

means for selecting one of said plurality of said programs;

circuitry for applying the output of the clock to the memory to generate a digital electric signal representative of the desired temperature at a particular time as stored in said selected program; and

means for receiving the electrical signal and the output of the memory and for generating a control signal for said specified temperature modifying device as a function of the difference between the ambient temperature and the desired temperature;

whereby, through the use of said means for selecting one of said programs the ambient temperature at the thermostat may be controlled in accordance

2. with different days of the week..Iaddend. .Iadd.19. A thermostat for controlling the application of electrical power to a specified electrically controlled temperature modifying device comprising:

a source of a periodically alternating electrical signal whose frequency is constant at ambient temperatures over the range of the thermostat;

a source of a periodically alternating electrical signal whose frequency varies as a function of the ambient temperature on the thermostat;

means for comparing the frequency of said constant frequency signal with the frequency of said varying frequency signal to generate a signal representing the ambient temperature on the thermostat;

a clock utilizing an output from said source of a constant frequency signal to generate digital electrical signals having values representative of real time;

a programmable, digital memory;

means for loading said memory with a plurality of separate programs for alternative use in controlling the specified temperature modifying device, each said program comprising digital signals representing desired temperatures at particular times over a twenty-four hour period;

means for selecting one of said plurality of programs;

circuitry for applying the output of the clock to the memory to generate a digital electric signal representative of the desired temperature at a particular time as stored in said selected program; and

means for receiving the signal having a characteristic which is a function of ambient temperature and the output of the memory and for generating a control signal for said specified temperature modifying device as a function of the difference between the ambient temperature and the desired temperature,

whereby, through use of said means for selecting one of said programs the ambient temperature at the thermostat may be controlled in accordance with

3. different days of the week..Iaddend. .Iadd.20. A thermostat for controlling the application of electrical power to a specified electrically controlled temperature modifying device comprising:

a source of a periodically alternating electrical signal whose frequency is constant at ambient temperatures over the range of the thermostat;

a source of a periodically alternating electrical signal whose frequency varies as a function of the ambient temperature on the thermostat, said variation being measured from a base frequency at a base temperature;

a counter for periodically generating a digital count representative of the difference between the current value of said temperature-variable frequency and the base frequency;

means for subtracting a digital base-temperature adjustment number from each said count and to derive from the result a digital signal representative of the ambient temperature on the thermostat;

a clock utilizing an output from said source of a constant frequency signal to generate digital electrical signals having values representative of real time;

a programmable, digital memory;

means for loading said memory with a plurality of separate programs for alternative use in controlling the specified temperature modifying device, each said program comprising digital signals representing desired temperatures at particular times over a twenty-four hour period;

means for selecting one of said plurality of programs;

circuitry for applying the output of the clock to the memory to generate a digital electric signal representative of the desired temperature at a particular time as stored in said selected program; and

means for receiving the electrical signal having a characteristic which is a function of ambient temperature and the output of the memory and for generating a control signal to the specified temperature modifying device as a function of the difference between the ambient temperature and the desired temperature;

whereby, through use of said means for selecting one of said programs the ambient temperature at the thermostat may be controlled in accordance with

4. different days of the week..Iaddend. .Iadd.21. A thermostat for controlling the application of electrical power to a specified electrically controlled temperature modifying device comprising:

a source of a periodically alternating electrical signal whose frequency is constant at ambient temperatures over the range of the thermostat;

a source of a periodically alternating electrical signal whose frequency varies as a function of the ambient temperature on the thermostat, said variation being measured from a base frequency at a base temperature;

a counter for periodically generating a digital count representative of the difference between the circuit value of said temperature-variable frequency and the base frequency;

means for dividing said count by a digital temperature-slope adjustment number and to derive from the result a digital signal representative of the ambient temperature on the thermostat;

a clock utilizing an output from said source of a constant frequency signal to generate digital electrical signals having values representative of real time;

a programmable, digital memory;

means for loading said memory with a plurality of separate programs for alternative use in controlling the specified temperature modifying device, each said program comprising digital signals representing desired temperatures at particular times over a twenty-four hour period;

means for selecting one of said plurality of programs;

circuitry for applying the output of the clock to the memory to generate a digital electric signal representative of the desired temperature at a particualr time as stored in said selected program; and

means for receiving the electrical signal having a characteristic which is a function of ambient temperature and the output of the memory and for generating a control signal to the specified temperature modifying device as a function of the difference between the ambient temperature and the desired temperature;

whereby, through use of said means for selecting one of said programs the ambient temperature at the thermostat may be controlled in accordance with

5. different days of the week..Iaddend. .Iadd.22. A thermostat for controlling the application of electrical power to a specified electrically controlled temperature modifying device comprising:

a source of a periodically alternating electrical signal whose frequency is constant at ambient temperatures over the range of the thermostat;

a source of a periodically alternating electrical signal whose frequency varies as a function of the ambient temperature on the thermostat, said variation being measured from a base frequency at a base temperature;

a counter for periodically generating a digital count representative of the difference between the current value of said temperature-variable frequency and the base frequency;

means for subtracting a digital base-temperature adjustment number from each said count to generat an intermediate result;

means for dividing said intermediate result by a digital temperature-slope adjustment number to generate a final result and to derive from the final result a digital signal representative of the ambient temperature on the thermostat;

a clock utilizing an output from said source of a constant frequency signal to generate digital electrical signals having values representative of real time;

a programmable, digital memory;

means for loading said memory with a plurality of separate programs for alternative use in controlling the specified temperature modifying device, each said program comprising digital signals representing desired temperatures at particular times over a twenty-four hour period;

means for selecting one of said plurality of programs;

circuitry for applying the output of the clock to the memory to generate a digital electric signal representative of the desired temperature at a particular time as stored in said selected program; and

means for receiving the electrical signal having a characteristic which is a function of ambient temperature and the output of the memory and for generating a control signal to the specified temperature modifying device as a function of the difference between the ambient temperature and the desired temperature;

whereby, through use of said means for selecting one of said programs the ambient temperature at the thermostat may be controlled in accordance with different days of the week..Iaddend. .Iadd.23. A thermostat for controlling the application of electrical power to a specified electrically controlled temperature modifying device comprising;

means for generating an electrical signal having a characteristic which varies as a function of the ambient temperature on the thermostat;

pi pi a clock operative to generate digital electrical signals having values representative of real time;

a source of a constant frequency, periodically alternating electrical signal forming part of both said means for generating an electrical signal having a characteristic which varies as a function of the ambient temperature on the thermostat and said clock;

a programmable, digital memory;

means for loading said memory with a plurality of separate programs for alternative use in controlling the specified temperature modifying device, each comprising digital signals representing desired temperatures at particular times over a twenty-four hour period;

means for selecting one of said plurality of programs;

circuitry for applying the output of the clock to the memory to generate a digital electric signal representative of the desired temperature at a particular time as stored in said selected program; and

means for receiving the electrical signal having a characteristic which is a function of ambient temperature and the output of the memory and for generating a control signal to the specified temperature modifying device as a function of their difference,

whereby, through use of said means for selecting one of said programs the ambient temperatures at the thermostat may be controlled in accordance with different days of the week..Iaddend.