DC Thermostat with Latching Relay Repulsing

• US 20150370270A1
• Filed: 06/18/2014
• Published: 12/24/2015
• Est. Priority Date: 06/18/2014
• Status: Active Grant

• Current Assignee: International Controls and Measurements Corporation
• Original Assignee: International Controls and Measurements Corporation
• Inventors: Pan, Weidong, Muench, Michael P., Kadah, Andrew S.
• Granted Patent: US 9,891,602 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: G05D 23/1902 characterised by the use of a variable reference value
• CPC Class Codes: G05F 1/463 Sources providing an output which depends on temperature

Abstract

A thermostat, of the type that employs latching relays to connect thermostat power to the various wires of the thermostat run, has a re-pulse feature that supplies latching pulses at a given interval, e.g., three hours, to ensure that the relays are in their proper state agreeing with the thermostat mode and the room temperature relative to the setpoint(s). In the case that the room air temperature is changing in a manner contrary to the current heating or cooling mode, which may indicate the latching relay has been knocked or bumped and needs to have its proper state re-established, the thermostat microprocessor issues pulses to the latching relay(s) more frequently, e.g., each 30 minutes, and the re-pulses may have a longer pulse width, e.g., increased from 20 ms to 25 ms.

Claims

1. Wall thermostat adapted to be mounted on a wall of a comfort space and coupled by a set of thermostat wires to a comfort air apparatus that provides heated or cooled air to said comfort space when the temperature of air in said comfort space reaches a temperature setpoint selected by an occupant of said comfort space;

and comprising

a housing adapted to be mounted on the wall of said comfort space;

a temperature sensing element in or on said housing;

a selector mechanism configured to permit the occupant to adjust said temperature setpoint;

a DC power source within said housing providing DC power at a battery voltage V_b;

a display on said housing;

a microprocessor within said housing adapted to control actuation of said comfort air apparatus to issue a call for heating or cooling when the comfort space temperature reaches a temperature based on said temperature setpoint and to control deactuation of said comfort air apparatus when the comfort air temperature changes from said temperature setpoint by a swing amount to end said call for heating or cooling;

said microprocessor including

power terminals connected with said DC power source;

one or more input terminals connected with said temperature sensing element;

one or more output terminals connected with said display; and

at least a first pair of output terminal ports;

at least one latching relay having ON and OFF inputs connected respectively to respective output ports of said at least one pair of output terminal ports of the microprocessor, said latching relay having a contact mechanism to connect thermostat power to one wire of said set of thermostat wires in response to a pulse from one output terminal port of said pair of output terminal ports and to disconnect thermostat power from said one wire in response to a pulse from the other output terminal port of said at least one pair of output terminal ports;

said microprocessor further including a re-pulsing functionality operative to sense if a call for heating or cooling is present and if so to issue pulses from said one output terminal port to the ON input of the associated latching relay at a predetermined interval and at a predetermined pulse width, and if a call for heating or cooling is absent to issue pulses from the other output terminal port to the OFF input of the associated latching relay at a predetermined interval and at a predetermined pulse width.

2. The wall thermostat according to claim 1, wherein said predetermined interval is at least 60 minutes.

3. The wall thermostat according to claim 2, wherein said predetermined interval is substantially 180 minutes.

4. The wall thermostat according to claim 1, said microprocessor further including a functionality operative, when there is a call for heating present and comfort space temperature is below said temperature setpoint, to provide pulses from said one output terminal to the ON input of the latching relay at a predetermined time interval shorter than the first-mentioned predetermined interval.

5. The wall thermostat according to claim 4 wherein said predetermined time interval is substantially 20 minutes.

6. The wall thermostat according to claim 1, said microprocessor further including a functionality operative, when there is a call for cooling present and comfort space temperature is above said temperature setpoint, to provide pulses from said one output terminal to the ON input of the latching relay at a predetermined time interval shorter than the first-mentioned predetermined interval.

7. The battery powered wall thermostat according to claim 6 wherein said predetermined time interval is substantially 20 minutes.

8. The wall thermostat according to claim 1, said microprocessor further including a functionality operative, when there is no call for heating present and comfort space temperature is above said temperature setpoint, to provide pulses from said other output terminal to the OFF input of the latching relay at a predetermined time interval shorter than the first-mentioned predetermined interval.

9. The wall thermostat according to claim 1, said microprocessor further including a functionality operative, when there is no call for cooling present and comfort space temperature is below said temperature setpoint, to provide pulses from said other output terminal to the OFF input of the latching relay at a predetermined time interval shorter than the first-mentioned predetermined interval.

10. The wall thermostat according to claim 1, said microprocessor further including a functionality operative, when there is a call for heating present and comfort space temperature is below said temperature setpoint, to provide pulses from said one output terminal to the ON input of the latching relay at a predetermined time interval shorter than the first-mentioned predetermined interval, and to provide said pulses at a pulse width increased over said predetermined pulse width.

11. The wall thermostat according to claim 1, said microprocessor further including a functionality operative, when there is a call for cooling present and comfort space temperature is above said temperature setpoint, to provide pulses from said one output terminal to the ON input of the latching relay at a predetermined time interval shorter than the first-mentioned predetermined interval, and to provide said pulses at a pulse width increased over said predetermined pulse width.

12. The wall thermostat according to claim 1, said microprocessor further including a functionality operative, when there is no call for heating present and comfort space temperature is above said temperature setpoint, to provide pulses from said other output terminal to the OFF input of the latching relay at a predetermined time interval shorter than the first-mentioned predetermined interval, and to provide said pulses at a pulse width increased over said predetermined pulse width.

13. The wall thermostat according to claim 1, said microprocessor further including a functionality operative, when there is no call for cooling present and comfort space temperature is below said temperature setpoint, to provide pulses from said other output terminal to the OFF input of the latching relay at a predetermined time interval shorter than the first-mentioned predetermined interval, and to provide said pulses at a pulse width increased over said predetermined pulse width.

14. The wall thermostat according to claim 1, said microprocessor further including a functionality operative, when there is a call for heating present and comfort space temperature is detected to be decreasing, to provide pulses from said one output terminal to the ON input of the latching relay at a predetermined time interval shorter than the first-mentioned predetermined interval, and to provide said pulses at a pulse width increased over said predetermined pulse width.

15. The wall thermostat according to claim 1, said microprocessor further including a functionality operative, when there is a call for cooling present and comfort space temperature is detected to be increasing, to provide pulses from said one output terminal to the ON input of the latching relay at a predetermined time interval shorter than the first-mentioned predetermined interval, and to provide said pulses at a pulse width increased over said predetermined pulse width.

16. The wall thermostat according to claim 1, said microprocessor further including a functionality operative, when there is no call for heating present and comfort space temperature is detected to be increasing, to provide pulses from said other output terminal to the OFF input of the latching relay at a predetermined time interval shorter than the first-mentioned predetermined interval, and to provide said pulses at a pulse width increased over said predetermined pulse width.

17. The wall thermostat according to claim 1, said microprocessor further including a functionality operative, when there is no call for cooling present and comfort space temperature is detected to be increasing, to provide pulses from said other output terminal to the OFF input of the latching relay at a predetermined time interval shorter than the first-mentioned predetermined interval, and to provide said pulses at a pulse width increased over said predetermined pulse width.

18. The wall thermostat according to claim 1, wherein said DC power source is comprised of one or more power cells.