Self calibrating, adaptive setpoint daylighting
A method and means for creating a daylight harvesting controller with a self calibrating light sensor and an adaptive setpoint that maintains a user determined light level is disclosed herein. The system includes a light sensor for monitoring the ambient light level of a designated control zone and a means to receive and interpret light level adjustment commands created by a user or user surrogate. The system includes means to limit the setpoint to a maximum value, suspend daylighting activity when lights are being adjusted or are turned off, and to delay setpoint capture and the start or resumption of daylighting until an adjustment cycle is completed and the zone light sources have reached a nominally steady state.
1. A method to dynamically capture a new setpoint for a daylighting-control zone, the method performed by a daylighting controller, said daylighting controller having at least one daylighting-control object, and comprising the steps of:
listening for a light-level-adjustment command being transmitted to one or more lighting-load-control objects controlling light sources in said daylighting-control object's control zone;
categorizing said light-level-adjustment command as On, Off, Raise/Lower, or Ignored;
when an applicable On or Raise/Lower command is detected, starting a setpoint-capture cycle;
suspending the daylighting operation of said daylighting-control zone until said setpoint-capture process has completed;
waiting for the current light-level-adjustment cycle to complete or be cancelled; and
when the current light-level-adjustment cycle has completed, reading and then writing the currently sensed light level of said daylighting-control object's control zone as the new setpoint of said daylighting-control object;
wherein:
no commands or other daylighting messaging listened for by said daylighting-control object within said daylighting-control zone need be processed through a central server or central processor, and
said daylighting controller can respond and operate autonomously and automatically throughout said setpoint-capture process without any manual user control to take said daylighting controller out of its normal mode of operation.
2. The method of claim 1 , wherein said new setpoint must be less than or equal to a maximum-allowed setpoint value.
3. The method of claim 1 , wherein said step of listening for a light-level-adjustment command is performed by passively and continuously monitoring all communications on a local lighting-control network to which all said local control devices and load controllers are connected.
4. The method of claim 3 , wherein said light-level-adjustment commands and associated communications comply with the DALI message protocol.
5. The method of claim 1 , wherein if said daylighting-control object categorizes said light-level-adjustment command as On, or Raise/Lower, then said step of responding to the detection of an applicable On or Raise/Lower command further includes cancelling any ongoing daylighting activity before starting a setpoint-capture cycle.
6. The method of claim 1 , wherein said light-level-adjustment commands may originate from user or user-surrogate devices, which are connected to either local or remote networks.
7. The method of claim 1 , further comprising the step of, if an applicable Off command is detected while said daylighting control is not in an idle state, then immediately canceling any ongoing daylighting activity and returning said daylighting-control object to its idle state.
8. The method of claim 1 , wherein the length of said setpoint-capture cycle is determined by a delay timer that is reset each time an On or Raise/Lower command is detected and/or when the sensed light level becomes nominally stable.
9. The method of claim 1 , wherein said step of reading said current light level may be performed by reading and then averaging the sensed light level of additional peripheral light sensors to achieve a single common ambient level for said daylighting-control zone.
10. The method of claim 1 , wherein: said daylighting-control object changes to a run state immediately after said writing of said new daylighting setpoint; and incremental adjustment commands are periodically and asynchronously transmitted to lighting-load-control objects controlling regulated light sources affecting the light level of said daylighting-control zone as needed to maintain said daylighting setpoint and as allowed by the output range of said lighting-load controllers.
11. The method of claim 10 , wherein the rate of daylighting adjustment is determined by a variable that sets the time delay between adjustments.
12. The method of claim 10 , wherein said regulated light sources include both electric lights and modulated sources of natural light.
13. A daylighting-control device configured to maintain a user or user-surrogate determined light level in a daylighting-control zone comprising:
a means for listening for messages being transmitted via a communications network;
a means for reading, interpreting, and categorizing said messages;
a means for sensing the current ambient light level of said daylighting-control zone;
a means for automatically suspending the daylighting operation of said daylighting-control device until a light-level-adjustment process has completed or has been cancelled;
a means for reading and then storing said ambient light level value as the setpoint of said daylighting-control device when a current light-level-adjustment cycle has completed;
a means for reading and comparing said ambient light level to said setpoint value; and
a means for transmitting light-level-adjustment commands;
wherein:
no commands or other daylighting messaging listened for by said daylighting-control device on said communications network need be processed through a central server or central processor, and
said daylighting-control device can respond and operate autonomously and automatically throughout said setpoint reading and storing process without any manual user control to take said daylighting-control device out of its normal mode of operation.
14. The device of claim 13 , wherein said means for sensing said current ambient light level includes one or more light-sensing devices located throughout said daylighting-control zone and connected via said communications network.
15. The device of claim 13 , wherein said communications network is a digital-lighting-control network that conforms to the DALI standard.
16. The device of claim 13 , wherein all physical components of the light-level-control system are hosted within a single physical node.
17. The device of claim 13 , wherein the physical components of the light-level-control system are hosted by separate physical nodes connected via said communications network.