Programmable thermostat employing a fail safe real time clock

• US 7,185,825 B1
• Filed: 06/24/2004
• Issued: 03/06/2007
• Est. Priority Date: 06/24/2004
• Status: Active Grant

• Current Assignee: Rosen Technologies LLC (IPValuation Partners, LLC)
• Original Assignee: Howard Rosen
• Inventors: Rosen, Howard
• Primary Examiner(s): NORMAN, MARC E
• Application Number:
  US10/875,579
• Time in Patent Office: 985 Days
• Field of Search: 236/94, 236/1.C, 236/46.R, 236/46.C, 621/57, 622/31, 700/275, 700/276
• US Class Current: 236/46.00C
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/32 Responding to malfunctions or emergencies
• CPC Class Codes: F24F 11/37 Resuming operation, e.g. after power outages; Emergency starting
• CPC Class Codes: F24F 11/61 using timers
• CPC Class Codes: F24F 11/64 using pre-stored data
• CPC Class Codes: F24F 2110/10 Temperature
• CPC Class Codes: G05B 2219/25251 Real time clock
• CPC Class Codes: G05B 2219/2614 HVAC, heating, ventillation, climate control

Abstract

A programmable thermostat for controlling space conditioning equipment receives power from the equipment. The thermostat has an interactive interface for user programming, a temperature sensor and a processor including: a central processing unit; a memory for storing program and data information, a real time clock and a non volatile random access memory. A control program stored in the memory causes the real time clock to periodically read its current time and date information into the non-volatile RAM. Upon restart after an outage, the time and date information stored in the non-volatile RAM is read into the real time clock to provide an acceptable time and date basis for resuming operation. Accordingly, the need for providing a backup power source, such as a battery or a supercap, is eliminated. In one exemplary embodiment, the thermostat also includes a receiver for accessing precision time and date signals from, for example, WWVB. The output of the receiver is used to periodically update the time and date in the real time clock such that, even after an outage, the real time clock will be accurate. If the receiver is not operating for some reason after an outage, then the real time clock will still be set from the non-volatile RAM.

Claims

1. A programmable thermostat for controlling space conditioning equipment comprising:

A) means coupling suitable power for energizing said thermostat from said space conditioning equipment to said thermostat;

B) an interactive interface for a user to enter programming information into said thermostat;

C) a temperature sensor for providing an electrical signal indicative of the temperature of a conditioned space in which the temperature sensor is situated;

D) a processor, said processor including;

1) a central processing unit;

2) a first memory coupled to said central processing unit for storing program and data information; and

3) an input/output unit including;

a) a sensor input coupled to said temperature sensor for receiving said electrical signal therefrom; and

b) a control output coupled to the space conditioning equipment for issuing control signals thereto;

4) a real time clock;

5) a non-volatile random access memory; and

6) a control program stored in said first memory directing;

a) said real time clock to periodically read its current time and date information into said non-volatile memory; and

b) upon restart after a loss and then return of power from said space conditioning equipment, read the time and date information stored in said non-volatile memory into said real time clock.

2. The thermostat of claim 1 in which said non-volatile random access memory is included in said first memory.

3. The thermostat of claim 2 which includes a vacation mode of operation.

4. The thermostat of claim 1 which includes a vacation mode of operation.

5. The thermostat of claim 1 which further includes a receiver adapted to receive current time and date information from an external source of the current time and date, said receiver being coupled to said real time clock such that the time and date information thereof is updated from said receiver.

6. The thermostat of claim 5 in which said receiver receives wireless signals from said external source.

7. The thermostat of claim 6 which includes a vacation mode of operation.

8. The thermostat of claim 5 in which said receiver receives signals via the Internet from said external source.

9. The thermostat of claim 8 which includes a vacation mode of operation.

10. The thermostat of claim 5 which includes a vacation mode of operation.

11. A programmable thermostat for controlling space conditioning equipment comprising:

A) means coupling suitable power for energizing said thermostat from said space conditioning equipment to said thermostat;

B) an interactive interface for a user to enter programming information into said thermostat;

C) a temperature sensor for providing an electrical signal indicative of the temperature of a conditioned space in which the temperature sensor is situated;

D) a processor, said processor including;

1) a central processing unit;

2) a first memory coupled to said central processing unit for storing program and data information; and

3) an input/output unit including;

a) a sensor input coupled to said temperature sensor for receiving said electrical signal therefrom; and

b) a control output coupled to the space conditioning equipment for issuing control signals thereto;

4) a real time clock; and

5) a receiver adapted to receive current time and date information from an external source of the current time and date, said receiver being coupled to said real time clock such that the time and date information thereof is updated from said receiver.

12. The thermostat of claim 11 in which said receiver receives wireless signals from said external source.

13. The thermostat of claim 12 which includes a vacation mode of operation.

14. The thermostat of claim 11 in which said receiver receives signals via the Internet from said external source.

15. The thermostat of claim 14 which includes a vacation mode of operation.

16. The thermostat of claim 11 which includes a vacation mode of operation.