Wall thermostat and the like

• US 4,373,664 A
• Filed: 05/14/1981
• Issued: 02/15/1983
• Est. Priority Date: 01/30/1980
• Status: Expired due to Term

• Current Assignee: Robertshaw Controls Company (Schneider Electric SE)
• Original Assignee: Robertshaw Controls Company (Schneider Electric SE)
• Inventors: Bauer, Frederick T., Barker, Charles E., Cairo, Anthony C., Jackson, Auzville Jr.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US06/263,730
• Time in Patent Office: 642 Days
• Field of Search: 364/557, 364/505, 236/46 R, 236/46 F, 236/78 R, 236/78 D, 165/12, 165/26, 340/309.3, 340/527
• US Class Current: 236/46.00R
• CPC Class Codes: F23N 2223/08 Microprocessor; Microcomputer
• CPC Class Codes: F23N 5/203 using electronic means
• 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: G05D 23/24 the sensing element having a resistance varying with temperature, e.g. a thermistor

Abstract

Apparatus is provided for a wall mounted thermostat to accept and convert manually generated instructions to binary encoded electronic impulses to control ambient air conditions in the environment in which the thermostat is located. The parameters of operation include a building heating control which reduces the desired ambient temperature at night, beginning at a prescribed time and returning to a higher daytime level at a different prescribed time. The system may also adjust desired temperature depending upon humidity conditions and alter the timing of heating and air conditioning control by predicting when a desired temperature will be reached in order to avoid overshoot. The system includes a liquid crystal or light emitting diode display and communicates with a power source and with heating and air conditioning switches such as relays or contactors.

Claims

1. An ambient air unitary self contained wall thermostat comprising:

ambient air temperature sensing providing analog signals indicative of actual temperature in an enclosed zone;

analog to digital conversion means for converting said signals indicative of actual temperature to binary encoded form;

means for storing a desired temperature in binary encoded form;

means for manually entering said desired temperature into said means for storing;

means for comparing said binary encoded signals indicative of actual desired temperatures and for providing an actuating signal to a heating or cooling source to conform said actual temperature to said desired temperature;

means for selectively suppressing response to prevent misleading transitory excursions of sensed temperature from average actual zone temperature; and

means responsive to the provisions of said actuating signal for determining the predicted time of coincidence of said actual temperature with said desired temperature in response to operation of said heating or cooling source and for responsively terminating generation of said actuating signal.

2. Apparatus according to claim 1 wherein said means for determining the predicted time of coincidence of said actual temperature and said desired temperature further comprises:

temperature gradient determining means coupled to said temperature sensing means for determining incremental temperature gradient during provision of said actuating signal,

means connected to said temperature gradient determining means and to said means for storing for calculating the predicted time at which actual temperature will coincide with said desired temperature at the rate of said incremental temperature gradient, and

means for terminating said activating signal prior to said predicted time to compensate for thermal inertia of said heating or cooling source.

3. Apparatus according to claim 1 wherein said means for suppressing response by preventing the provision of said actuating signal includes buffer storage means interposed between said analog to digital converter and said means for comparing, said buffer storage means for accumulating successive ones of said signals indicative of actual temperature to provide an output to said means for comparing indicative of an average of actual temperature over a prescribed interval of time.

4. Apparatus according to claim 1 further comprising:

temperature averaging means interposed between said temperature sensing means and said means for comparing, said temperature averaging means for averaging a plurality of successive temperature signals from said temperature sensing means and for enabling said means for comparing to provide said activating signal when average actual temperature deviates from said selected desired temperature by more than a predetermined allowable limit.

5. Apparatus according to claim 1 further characterized in that said means for selectively suppressing response to misleading transitory excursions, includes clock means for designating sampling times, and for actuating said ambient air temperature sensing means for computing a mean ambient air temperature from said binary encoded analog signals indicative of actual temperature provided at said sampling times, whereby said means for comparing said binary encoded signals provides an actuating signal when said ambient air temperature deviates from said desired temperature.

6. Apparatus according to claim 5, further comprising means for storing a maximum allowable deviation between mean ambient air temperature and desired temperature, whereby said means for comparing provides an actuating signal only when said mean ambient air temperature deviates from said desired temperature by at least said maximum allowable deviation.

7. Apparatus according to claim 1 further characterized in that said means for selectively suppressing response to misleading transitory excursions determines direction and cumulative magnitude of departure of sensed temperature from average actual zone temperature over a prescribed interval of time.

8. A wall thermostat comprising:

ambient air temperature sensing means providing analog signals indicative of actual zone temperature in an enclosed zone,

analog to digital conversion means for converting said signals indicative of actual temperature to binary encoded form,

means for storing a desired temperature in binary encoded form,

means for manually entering said desired temperature into said means for storing,

means for comparing said binary encoded signals indicative of actual and desired temperatures and for providing an actuating signal to a heating or cooling source to conform said actual temperature to said desired temperature, and

means responsive to the provision of said actuating signal for determining the predicted time of coincidence of said actual temperature with said desired temperature in response to operation of said heating or cooling source and for responsively terminating generation of said actuating signal.

9. Apparatus according to claim 8, wherein said means for determining the predicted time of coincidence of said actual temperature and said desired temperature further comprises:

temperature gradient determining means coupled to said temperature sensing means for determining incremental temperature gradient during provision of said actuating signal,

means connected to said temperature gradient determining means and to said means for storing for calculating the predicted time at which actual temperature will coincide with said desired temperature at the rate of said incremental temperature gradient, and

means for terminating said actuating signal prior to said predicted time to compensate for thermal inertia of said heating or cooling source.