# US 2014/0156079 A1 · Method of controlling a motorized window treatment

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- Number: US 2014/0156079 A1
- Document ID: US20140156079A1
- Status: Published application
- Kind: A1
- Application number: 13/838,876
- Filed: 2013-03-15
- Published: 2014-06-05
- Earliest claimed: 2012-11-30
- Assignees: Lutron Electronics Co., Inc.
- Applicants: Lutron Electronics Co., Inc.
- Inventors: Brian Michael Courtney; Timothy Gill; Shilpa Sarode
- Web page: https://patentgrep.com/patent/US20140156079A1

## CPC

- G05B 15/02: electric
- E06B 9/32: Operating, guiding, or securing devices therefor (operation of tilting bars E06B9/307)
- E06B 9/68: Operating devices or mechanisms, e.g. with electric drive
- E06B 2009/6809: {Control}
- E06B 2009/6827: {sensing light}
- Y02A 30/24: Structural elements or technologies for improving thermal insulation
- Y02B 80/00: Architectural or constructional elements improving the thermal performance of buildings
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- E06B: FIXED OR MOVABLE CLOSURES FOR OPENINGS IN BUILDINGS, VEHICLES, FENCES OR LIKE ENCLOSURES IN GENERAL, e.g. DOORS, WINDOWS, BLINDS, GATES (shades or blinds for greenhouses A01G9/22; curtains A47H; lids for car boots or bonnets B62D25/10; skylights E04B7/18; sunshades, awnings E04F10/00)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

A method comprises measuring a light intensity at a window; determining if the light intensity exceeds a cloudy-day threshold; operating in a sunlight penetration limiting mode to control the motorized window treatment to control the sunlight penetration distance in the space; enabling the sunlight penetration limiting mode if the light intensity is greater than the cloudy-day threshold; and disabling the sunlight penetration limiting mode if the total lighting intensity is less than the cloudy-day threshold. The cloudy-day threshold is maintained at a constant threshold if a calculated solar elevation angle is greater than a predetermined solar elevation angle, and the cloudy-day threshold varies with time if the calculated solar elevation angle is less than the predetermined solar elevation angle. The cloudy-day threshold is a function of the calculated solar elevation angle if the calculated solar elevation angle is less than the predetermined solar elevation angle.

## Claims

### Claim 1

A method of controlling a motorized window treatment positioned adjacent to a window on a wall of a building, the method comprising:
sampling a light intensity outside of the building;
computing a rate of change of the light intensity;
automatically controlling movement of the window treatment in a sunny operation mode if the absolute value of the computed rate of change is at least a first threshold value; and
automatically controlling movement of the window treatment in a cloudy operation mode if the absolute value of the computed rate of change is less than the first threshold value and the light intensity is less than a second threshold value.

### Claim 2 (depends on 1)

The method of claim 1, further comprising automatically controlling movement of the window treatment in the sunny operation mode if the absolute value of the computed rate of change is less than the first threshold value and the light intensity is at least the second threshold value.

### Claim 3 (depends on 1)

The method of claim 1 wherein the step of computing the rate of change includes:
summing or averaging the sampled light intensity over each of a plurality of intervals to provide a respective intensity value for each respective interval; and
calculating the rate of change as the difference between ones of the intensity values divided by a length of one of the intervals.

### Claim 4 (depends on 1)

The method of claim 1 wherein the step of computing the rate of change includes:
calculating the rate of change as the difference between first and second sampled light intensities divided by a length of time between sampling the first light intensity and sampling the second light intensity.

### Claim 5 (depends on 1)

The method of claim 1, wherein the step of controlling movement of the window treatment in the sunny operation mode includes:
moving the window treatment to a first position if the light intensity is at least a third threshold value; and
moving the window treatment to a second position if the light intensity is less than the third threshold value.

### Claim 6 (depends on 1)

The method of claim 1, wherein the step of controlling movement of the window treatment in the sunny operation mode includes:
moving the window treatment to a position that is a function of the light intensity.

### Claim 7 (depends on 1)

The method of claim 1, wherein the step of controlling movement of the window treatment in the sunny operation mode includes:
moving the window treatment to a position that is a linear function of the light intensity.

### Claim 8 (depends on 1)

The method of claim 1, wherein the step of automatically controlling movement of the window treatment in a cloudy operation mode includes:
moving the window treatment to a visor position while the absolute value of the computed rate of change is less than the first threshold value.

### Claim 9 (depends on 7)

The method of claim 7, wherein a third threshold value is lower than the first threshold value, and the rate of change of the light intensity is computed more frequently when the absolute value of the computed rate of change is between the first threshold value and the third threshold value than when the absolute value of the computed rate of change is between zero and the third threshold value.

### Claim 10

A method of controlling a motorized window treatment positioned adjacent to a window on a wall of a building, the method comprising:
(a) sampling a light intensity outside of the building;
(b) computing a rate of change of the light intensity;
(c) automatically controlling movement of the window treatment based on the light intensity if the absolute value of the light intensity is at least a first threshold value; and
(d) automatically controlling movement of the window treatment based at least partially on a rate of change of the light intensity if the absolute value of the light intensity is less than the first threshold value.

### Claim 11 (depends on 10)

The method of claim 10, wherein step (d) includes moving the window treatment to a first position if the absolute value of the rate of change of the light intensity is at least a second threshold value.

### Claim 12 (depends on 11)

The method of claim 11, wherein step (d) includes moving the window treatment to a second position if the absolute value of rate of change of the light intensity is less than the second threshold value.

### Claim 13 (depends on 10)

The method of claim 10, wherein step (d) includes moving the window treatment to a position that varies as a function of the light intensity if the absolute value of the rate of change of the light intensity is less than a second threshold value.

### Claim 14 (depends on 10)

The method of claim 10, wherein step (d) includes:
controlling the window treatment in a sunny day mode if the absolute value of the rate of change of the light intensity is greater than or equal to a second threshold value; and
controlling the window treatment in a cloudy day mode if the absolute value of the rate of change of the light intensity is less than a threshold value.

### Claim 15 (depends on 14)

The method of claim 14, wherein the step of controlling the window treatment in a sunny day mode includes causing the window treatment to remain in a sunny day position for at least a predetermined minimum time period before transitioning to a cloudy day position.

### Claim 16 (depends on 14)

The method of claim 14, wherein the step of controlling the window treatment in the cloudy day mode includes transitioning to control the window treatment in the sunny day mode immediately upon determining that the absolute value of the rate of change of the light intensity has increased to at least the first threshold value.

### Claim 17 (depends on 1)

The method of claim 1, wherein the method includes hysteresis, such that the automatically controlling steps transition between the sunny operation mode and the cloudy operation mode when the rate of change of the light intensity passes through a sunny threshold and a cloudy threshold, wherein the sunny threshold is higher than the cloudy threshold.

### Claim 18

A method of controlling a motorized window treatment for adjusting the amount of sunlight entering a space of a building through a window to control a sunlight penetration distance in the space, the method comprising:
measuring a total light intensity at the window;
calculating a solar elevation angle;
calculating a cloudy-day threshold as a function of the calculated solar elevation angle;
determining if the total light intensity exceeds the cloudy-day threshold;
operating in a sunlight penetration limiting mode to control the motorized window treatment to thus control the sunlight penetration distance in the space;
enabling the sunlight penetration limiting mode if the total light intensity is greater than the cloudy-day threshold; and
disabling the sunlight penetration limiting mode if the total lighting intensity is less than the cloudy-day threshold.

### Claim 19 (depends on 18)

The method of claim 18, wherein the cloudy-day threshold is maintained at a constant threshold if the calculated solar elevation angle is greater than a predetermined solar elevation angle, and the cloudy-day threshold is a function of the calculated solar elevation angle if the calculated solar elevation angle is less than the predetermined solar elevation angle.

### Claim 20 (depends on 19)

The method of claim 19, wherein the cloudy-day threshold is a linear function of the calculated solar elevation angle if the calculated solar elevation angle is less than the predetermined solar elevation angle.

### Claim 21 (depends on 18)

The method of claim 18, further comprising:
controlling the motorized window treatment to a predetermined position when the sunlight penetration limiting mode is disabled.

### Claim 22

A method of controlling a motorized window treatment for adjusting the amount of sunlight entering a space of a building through a window to control a sunlight penetration distance in the space, the method comprising:
measuring a total light intensity at the window;
determining if the total light intensity exceeds a cloudy-day threshold;
operating in a sunlight penetration limiting mode to control the motorized window treatment to thus control the sunlight penetration distance in the space;
enabling the sunlight penetration limiting mode if the total light intensity is greater than the cloudy-day threshold; and
disabling the sunlight penetration limiting mode if the total lighting intensity is less than the cloudy-day threshold;
wherein the cloudy-day threshold varies with time around sunrise and sunset, and is maintained at a constant threshold near midday.

### Claim 23 (depends on 22)

The method of claim 22, wherein the cloudy-day threshold varies with time if a calculated solar elevation angle is less than a predetermined solar elevation angle, and is maintained at the constant threshold if the calculated solar elevation angle is greater than the predetermined solar elevation angle.

### Claim 24 (depends on 23)

The method of claim 23, wherein the cloudy-day threshold is a function of the calculated solar elevation angle if the calculated solar elevation angle is less than the predetermined solar elevation angle.

### Claim 25 (depends on 24)

The method of claim 24, wherein the cloudy-day threshold is a linear function of the calculated solar elevation angle if the calculated solar elevation angle is less than the predetermined solar elevation angle.

### Claim 26 (depends on 22)

The method of claim 22, wherein the cloudy-day threshold varies with time for a first predetermined time period after sunrise and a second predetermined time period before sunset.

### Claim 27 (depends on 22)

The method of claim 22, further comprising:
controlling the motorized window treatment to a predetermined position when the sunlight penetration limiting mode is disabled.

### Claim 28

A system comprising:
a motorized window treatment adapted to be positioned adjacent to a window on a wall of a building:
a sensor for sampling a light intensity outside of the building; and
a processor configured to:
compute a rate of change of the light intensity,
automatically control movement of the window treatment in a sunny operation mode if the absolute value of the computed rate of change is at least a first threshold value, and
automatically control movement of the window treatment in a cloudy operation mode if the absolute value of the computed rate of change is less than the first threshold value and the light intensity is less than a second threshold value.

### Claim 29 (depends on 28)

The system of claim 28, wherein the processor is further configured to automatically control movement of the window treatment in the sunny operation mode if the absolute value of the computed rate of change is less than the first threshold value and the light intensity is at least the second threshold value.

### Claim 30 (depends on 28)

The system of claim 28, wherein controlling movement of the window treatment in the sunny operation mode includes:
moving the window treatment to a first position if the light intensity is at least a third threshold value; and
moving the window treatment to a second position if the light intensity is less than the third threshold value.

### Claim 31

A system comprising:
a motorized window treatment adapted to be positioned adjacent to a window on a wall of a building, comprising:
a sensor for sampling a light intensity outside of the building; and
a processor configured for:
computing a rate of change of the light intensity;
automatically controlling movement of the window treatment based on the light intensity if the absolute value of the light intensity is at least a first threshold value; and
automatically controlling movement of the window treatment based at least partially on a rate of change of the light intensity if the absolute value of the light intensity is less than the first threshold value.

### Claim 32 (depends on 31)

The system of claim 31, wherein the processor is configured for moving the window treatment to a first position if the absolute value of the rate of change of the light intensity is at least a second threshold value.

### Claim 33 (depends on 32)

The system of claim 32, wherein the processor is configured for moving the window treatment to a second position if the absolute value of rate of change of the light intensity is less than the second threshold value.

### Claim 34 (depends on 31)

The system of claim 31, wherein the processor is configured for:
controlling the window treatment in a sunny day mode if the absolute value of the rate of change of the light intensity is greater than or equal to a second threshold value; and
controlling the window treatment in a cloudy day mode if the absolute value of the rate of change of the light intensity is less than a threshold value.

### Claim 35 (depends on 34)

The system of claim 34, wherein the step of controlling the window treatment in a sunny day mode includes causing the window treatment to remain in a sunny day position for at least a predetermined minimum time period before transitioning to a cloudy day position.

### Claim 36 (depends on 31)

The system of claim 31, wherein the method includes hysteresis, such that the automatically controlling steps transition between the sunny operation mode and the cloudy operation mode when the rate of change of the light intensity passes through a sunny threshold and a cloudy threshold, wherein the sunny threshold is higher than the cloudy threshold.

### Claim 37

A system for controlling a motorized window treatment for adjusting the amount of sunlight entering a space of a building through a window to control a sunlight penetration distance in the space, comprising:
a sensor for measuring a total light intensity at the window; and
a processor configured for:
calculating a solar elevation angle;
calculating a cloudy-day threshold as a function of the calculated solar elevation angle;
determining if the total light intensity exceeds the cloudy-day threshold;
operating in a sunlight penetration limiting mode to control the motorized window treatment to thus control the sunlight penetration distance in the space;
enabling the sunlight penetration limiting mode if the total light intensity is greater than the cloudy-day threshold; and
disabling the sunlight penetration limiting mode if the total lighting intensity is less than the cloudy-day threshold.

### Claim 38 (depends on 37)

The system of claim 37, wherein the cloudy-day threshold is maintained at a constant threshold if the calculated solar elevation angle is greater than a predetermined solar elevation angle, and the cloudy-day threshold is a function of the calculated solar elevation angle if the calculated solar elevation angle is less than the predetermined solar elevation angle.

### Claim 39 (depends on 37)

The system of claim 37, wherein the processor is configured to control the motorized window treatment to a predetermined position when the sunlight penetration limiting mode is disabled.

### Claim 40

A system for controlling a motorized window treatment for adjusting the amount of sunlight entering a space of a building through a window to control a sunlight penetration distance in the space, comprising:
a sensor for measuring a total light intensity at the window; and
a processor configured for:
determining if the total light intensity exceeds a cloudy-day threshold;
operating in a sunlight penetration limiting mode to control the motorized window treatment to thus control the sunlight penetration distance in the space;
enabling the sunlight penetration limiting mode if the total light intensity is greater than the cloudy-day threshold; and
disabling the sunlight penetration limiting mode if the total lighting intensity is less than the cloudy-day threshold;
wherein the cloudy-day threshold varies with time around sunrise and sunset, and is maintained at a constant threshold near midday.

### Claim 41 (depends on 40)

The system of claim 40, wherein the cloudy-day threshold varies with time if a calculated solar elevation angle is less than a predetermined solar elevation angle, and is maintained at the constant threshold if the calculated solar elevation angle is greater than the predetermined solar elevation angle.

### Claim 42 (depends on 41)

The system of claim 41, wherein the cloudy-day threshold is a function of the calculated solar elevation angle if the calculated solar elevation angle is less than the predetermined solar elevation angle.

### Claim 43 (depends on 40)

The system of claim 40, wherein the cloudy-day threshold varies with time for a first predetermined time period after sunrise and a second predetermined time period before sunset.