Occupancy sensor having automated hysteresis adjustment for open-loop daylighting operation

• US 9,370,080 B2
• Filed: 01/11/2016
• Issued: 06/14/2016
• Est. Priority Date: 02/25/2013
• Status: Expired due to Fees

• Current Assignee: Leviton Manufacturing Company Incorporated
• Original Assignee: Leviton Manufacturing Company Incorporated
• Inventors: Leinen, Richard A.
• Primary Examiner(s): Le, Tung X
• Application Number:
  US14/992,157
• Publication Number:
  US 20160128166A1
• Time in Patent Office: 155 Days
• Field of Search: 315149-159, 315/291, 315/307, 315/312
• US Class Current: 1/1
• CPC Class Codes: F21S 8/006 Solar simulators, e.g. for testing photovoltaic panels
• CPC Class Codes: H05B 47/10 Controlling the light source
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/115 by determining the presence or movement of objects or living beings
• CPC Class Codes: H05B 47/19 via wireless transmission
• CPC Class Codes: H05B 47/1965 using handheld communication devices
• CPC Class Codes: H05B 47/20 Responsive to malfunctions or to light source life; for protection
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

A system and method provide fail-safe operation of a lighting system. A lighting level detector is used to obtain a baseline lighting level for a low-intensity light. If the detector measures less than the baseline level when an occupancy sensor determines the space is unoccupied, a high-intensity light is energized and an indication is provided to a user that the low-intensity light has failed. A method provides daylighting operation of a lighting system. An occupancy sensor can have Wi-Fi functionality to enable remote configuration of the sensor. A line voltage occupancy sensor can include an interface with low voltage devices. An occupancy sensor can include an integral interface to enable an external control system to override the sensor'"'"'s normal logic under emergency conditions. An occupancy sensor can include an active temperature compensation feature. An occupancy sensor can also incorporate an automatically adjustable coverage area.

Claims

1. A sensor, comprising:

a housing;

a light sensor located in the housing, the light sensor for detecting ambient light levels in the monitored space;

a processor communicatively coupled to the light sensor; and

a load control device communicatively coupled to the processor, the load control device coupled to a load for selectively energizing and de-energizing the load in response to a signal received from the processor;

wherein the processor is programmed to perform an open-loop daylighting calibration routine for calculating an amount of light contributed by the load and using the calculated amount of light to automatically adjust a sensed light level at which the load is being energized or de-energized.

2. The sensor of claim 1, wherein the processor is programmed to automatically perform the open-loop daylighting calibration routine.

3. The sensor of claim 1, wherein the processor is programmed to automatically perform the open-loop daylighting calibration routine when a manual set point for the light sensor is being set.

4. The occupancy sensor of claim 1, wherein the open-loop daylighting calibration routine comprises automatically energizing and de-energizing the load and calculating a change in the amount of light detected by the light sensor between the energized and de-energized states of the load, the calculated change comprising the amount of light contributed by the load.

5. The sensor of claim 4, wherein the open-loop daylighting calibration routine comprises automatically energizing and de-energizing the load a plurality of times to calculate the change in the amount of light detected by the light sensor.

6. The sensor of claim 4, wherein the processor is programmed to calculate a hysteresis value based on the calculated change, the hysteresis value being greater than the amount of light contributed by the load.

7. The sensor of claim 6, wherein the hysteresis value is more than twice the amount of light contributed by the load.

8. The sensor of claim 6, further comprising non-volatile memory coupled to the processor, the hysteresis value stored in the non-volatile memory.

9. The sensor of claim 6, the processor programmed to command the load control device to de-energize the load when the light sensor detects an ambient light level exceeding a predetermined system set point, the first predetermined system set point being based on the hysteresis value.

10. The sensor of claim 1, the sensor further comprising, an occupancy sensing element located in the housing, the occupancy sensing element for sensing an occupancy condition of a monitored space, the processor being communicatively coupled to the occupancy sensor.

11. A sensor, comprising:

a housing;

an occupancy sensing element, the occupancy sensing element for sensing an occupancy condition of a monitored space;

a light sensor for detecting ambient light levels in the monitored space;

a processor communicatively coupled to the occupancy sensing element and the light sensor; and

a load control device communicatively coupled to the processor, the load control device further coupled to a load for selectively energizing and de-energizing the load in response to signals received from the processor based on the occupancy condition sensed by the occupancy sensing element;

wherein the processor is programmed to perform an open-loop daylighting calibration routine for calculating an amount of light contributed by the load and using the calculated amount of light to automatically adjust a sensed light level at which the load is being energized or de-energized.

12. The sensor of claim 11, wherein the load control device, the occupancy sensor, the light sensor, and the processor are all located in the housing.

13. The sensor of claim 11, wherein the open-loop daylighting calibration routine comprises automatically energizing and de-energizing the load a plurality of times and calculating a change in the amount of light detected by the light sensor between the energized and de-energized states of the load, the calculated change in the amount of light comprising the amount of light contributed by the load.

14. The sensor of claim 13, wherein the processor is programmed to calculate a hysteresis value based on the calculated change in the amount of light, the hysteresis value being greater than the amount of light contributed by the load.

15. The sensor of claim 14, wherein the hysteresis value is greater than twice the amount of light contributed by the load.

16. The sensor of claim 15, the processor programmed to command the load control device to de-energize the load when the light sensor detects an ambient light level exceeding a predetermined system set point, the first predetermined system set point being based on the hysteresis value.

17. The sensor of claim 16, further comprising a software timeout to delay the de-energizing of the load when the light sensor detects ambient light level exceeding a predetermined system set point.

18. A method for open loop daylighting, comprising:

determining, via a light sensor, an ambient light level of a monitored space;

determining, via a processor associated with the light sensor, whether the light level is less than a first predetermined light level or is greater than a second predetermined light level;

performing, at the processor, an open-loop daylighting calibration routine for determining the amount of light contributed by the load;

commanding, by the processor, a load control device to energize a load associated with the monitored space when the light level is determined to be less than the first predetermined light level;

commanding, by the processor, the load control device to de-energize the load associated with the monitored space when the light level exceeds the second predetermined value;

wherein the difference between the first and second predetermined light levels is more than two times the amount of light contributed by the load.

19. The method of claim 18, further comprising automatically performing the open-loop daylighting routine when a manual set point of the light sensor is programmed.

20. The method of claim 18, further comprising using a software timeout to delay the energizing of the load when the light sensor detects that the ambient light level is less than the first predetermined value, and to delay the de-energizing of the load when the light sensor detects that the ambient light level is greater than the second predetermined value.