Lighting control system with priority override

A lighting control system for controlling the brightness of a lamp in accordance with the minimum lighting needs of an environment in which the lamp is used, said system comprising:

• (a) adjustable control means for producing a first signal having a value representing a first desired lamp brightness, said adjustable control means having a manually movable actuator for selectively determining the value of said first signal;
• (b) occupant-sensing means for sensing the absence of a human being in said environment and, in response to detecting such absence for a predetermined time interval, for selectively producing a second signal, said second signal having a value representing a second desired lamp brightness;
• and
• (c) a logic and control unit comprising (i) means for comparing the respective values of said first and second signals and for producing an output signal to cause the lamp to operate at the lower of the first and second desired lamp brightnesses, and (ii) means responsive to movement of said actuator for overriding the output of said comparing means to cause the lamp brightness to be determined only by said first signal, said logic and control means operating to change lighting levels at a preset rate when said second signal determines the desired lamp brightness, and at a faster rate when said first signal determines the desired lamp intensity.

Alighting control system for controlling a fluorescent dimming ballast to adjust the brightness of a fluorescent lamp controlled by such ballast in accordance with the minimum lighting needs of an environment in which the lamp is used, said system comprising:

• (a) adjustable dimming means for producing a first signal having a value representing a first desired lamp brightness in said environment, said dimming means having a manually movable actuator for adjusting the value of said first signal;
• (b) occupant sensing means for sensing the absence of a human being in said environment and, in response to detecting such absence for a predetermined time interval, for selectively producing a second signal, said second signal having a value representing a second desired lamp brightness in said environment;
• and
• (c) a logic and control unit comprising:
• (i) means for comparing the respective values of said first and second signals and for producing an output signal to said ballast to cause the lamp to operate at the lower of the first and second desired lamp brightnesses, and (ii) means responsive to movement of said actuator for overriding the output of said comparing means to cause the lamp brightness to be determined only by said first signal, said logic and control means operating to change lighting levels at a preset rate when said second signal determines the desired lamp brightness, and at a faster rate when said first signal determines the desired lamp intensity.

A lighting control system for controlling the voltage applied to a fluorescent dimming ballast to adjust the brightness of a fluorescent lamp controlled by such ballast in accordance with the minimum lighting needs of an environment in which the lamp is used, said system comprising:

• (a) adjustable dimming means for producing a first signal having a value representing a first desired lamp brightness in said environment, said dimming means having a manually movable actuator for adjusting the value of said first signal;
• (b) occupant sensing means for sensing the absence of a human being in said environment and, in response to detecting such absence for a predetermined time interval, for selectively producing a second signal, said second signal having a value representing a second desired lamp brightness in said environment;
• (c) photosensing means for sensing the level of natural light in such environment and for producing a third signal having a value representing a third desired lamp brightness;and
• (d) a microprocessor-based logic and control unit comprising:
• (i) means for comparing the respective values of said first, second and third signals and for producing an output signal to said ballast to cause the lamp to operate at the lowest of the first, second and third desired lamp brightnesses, and (ii) means responsive to movement of said actuator for overriding the output of said comparing means to cause the lamp brightness to be determined only by said first signal, said logic and control means operating to change lighting levels at a preset rate when said second signal determines the desired lamp brightness, and at a faster rate when said first signal determines the desired lamp intensity.

A lighting control system for controlling the brightness of a lamp in accordance with the minimum lighting needs of an environment in which the lamp is used, said system comprising:

• (a) adjustable control means for producing a first signal having a value representing a first desired lamp brightness;
• (b) occupant-sensing means for sensing the absence of a human being in the environment and, in response to detecting such absence for a predetermined time interval, for selectively producing a second signal, such second signal having a value representing a second desired lamp brightness;
• and
• (c) a logic and control unit comprising:
• (i) means for comparing the respective values of the first and second signals and for producing an output signal to cause the lamp to operate at the lower of the first and second desired lamp brightnesses, and (ii) means responsive to a third signal indicating a need for full lamp brightness for overriding the output of the comparing means to cause the lamp brightness to be determined only by the third signal.

A lighting control system for controlling the power applied to a lamp to control the brightness of the lamp in accordance with the minimum lighting needs of an environment in which the lamp is used, said system comprising:

• (a) occupant-sensing means for sensing the presence of a human being in the environment;
• (b) logic and control means coupled to said occupant sensor for setting the lamp brightness at a first level when the presence of a human being is sensed, and for setting the lamp brightness at a second level lower than said first level when no such presence is sensed;
• and
• (c) a time clock for producing a signal indicating the time of day, said logic and control means being responsive to said time clock signal to set the lamp brightness to zero at certain times of day and to be set at said second level at other times of day when the environment is unoccupied.