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© 2014-2021 Acuity Brands Lighting, Inc. All rights reserved. Rev. 12/28/21
nCM ADCX (PC) RJB - TN-140-001
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PHOTOCELL OPERATION
The nCM ADCX RJB sensor continuously adjusts a space’s lighting to achieve maximum daylight harvesting while maintaining a minimum light level, referred
to as the set-point. When no daylight is available, the sensor allows the controlled dimmable lighting to operate at its full bright level. As daylight increases and
begins to contribute to the overall light level of the room, the Automatic Dimming Control (ADC) feature starts dimming the room proportionally, eventually
reaching the full dim level (or optionally switching off, see paragraph below). As the daylight levels fall, the ADC feature will again take control of the lights;
reducing the dim level (increasing the brightness) in order to achieve the necessary total light level. At the point when all daylight contribution is gone,
lighting will be back at its full bright level.
The nCM PC RJB sensor does not control dimming, but instead signals nLight devices located elsewhere within the sensor’s zone to switch a controlled lighting
load on when more light is needed. The lights are also signaled to turn off when light is above the set-point plus a 10% safety factor and deadband. The safety
factor will prevent the system from cycling when the light level is very near the set-point. The deadband is the level of light contributed by the artificial lights
being controlled. This level is tracked so if the lighting conditions change (for example a lamp burns out) the point at which the lights turn off is adapted
accordingly. If the photocell can not view the lights being controlled (for example if it is looking up at skylights), there is no deadband and the sensor is said to
be working open loop. There is also an adaptive cloud delay (optional) before the photocell turns the lights off to prevent the system from cycling on a cloudy
day.
AMPLE DAYLIGHT
Set-point
Lights Turn
ON
Lights Turn
OFF
DEADB
AND
NO DAYLIGHT
AMPLE DAYLIGHT
Set-point
Lights Full
ON
Lights Full
DIM
DIMMING
ON/OFF CONTROL (nCM PC RJB)
AUTOMATIC DIMMING (nCM ADCX RJB)
