Application Notes
Daylighting Control
Sensor Location Guidelines (in this order of prescedence)
• According to occupancy sensor placement rules (applicable for combination units only)
• Outside the direct cone of light from indirect fixtures
• As close to the fixture being controlled as possible
• Between 6 and 15 feet from window
• Above the least illuminated space in work areas
• Away from spaces exposed to direct beam sunlight
• Away from lighting that it is not controlling
Following these guidelines as closely as possible will:
• Improve the close loop operation of the sensor
• Result in better Auto Set-Point selection
• Allow for greater dynamic range of dimming (-ADC option only)
General Programming Instructions
All sensor programming is done by pressing the button on the side of the unit the number of times corresponding to the function or selection desired.
1. Enter function number (FN #) i.e., press button five times to enter FN #5 (Set-Point 10’s Digit).
2. LED will blink back the current FN’s setting: i.e., 2 blinks for 20 foot candles
(see table).
3. Press button the number of times for new desired setting:
i.e, press one time for 10 foot candles
Note: The LED will blink back the new setting three times as confirmation. You must let the LED blink this new setting back all three times before continuing to another function.
Automatic Set-Point Selection Procedure
1.
2.
3.
4.
5.
Press Button four times to enter Function 4 (FN #4).
Press Button four times to engage Automatic Set-Point (Setting 4).
LED will begin to blink quickly indicating you have 30 seconds to move away from sensor and assure no shadows are being cast.
Sensors with the -ADC option will then dim the lights to various levels. Sensors w/
an On/Off Photocell (-PC, -P, or -PD option) will just cycle the lights. During this
process the sensor is taking readings to determine how much light it is controlling. This value is used in calculating the Auto Set-Point and Deadband.
After this cycle, the sensor will drive the lights to the level necessary to maintain the Set-Point.
Note: If after the Auto Set-Point calibration procedure the light level is too high/ low for
user’s preference, refer to the table on page 2 of this document to determine recommended adjustments.
Setting Dim Range
To modify the upper or lower limits of the dimming range, use FN #15 and FN #16.
G001-002
Calculating Sunlight Discount Factor
Because all rooms have different reflective characteristics, a variable sunlight discount factor is used to improve the sensor’s tracking accuracy during periods of high daylight. To determine if changes to the default sunlight discount factor are necessary, make the
following general assessments about the room where the sensor is located.
Begin calculations at the default sunlight discount factor of 4, and then use FN#7 to a select new factor if necessary (see Note).
Flooring
a.
if shiny or white tile, add 1.
b.
if dark carpet, subtract 1.
Proximity of Photocell to Window
a.
if less than 7ft, add 1.
b.
if more than 10ft, subtract 1.
Lighting Direction
a.
if room frequently receives direct sunlight, add 1.
b.
if room seldom receives direct sunlight (eg. North facing window), subtract 1.
Space Utilization
a.
for office type workspaces, add 1.
b.
for non-workspaces (hallway, vestibules), subtract 1.
Note: For open loop application always set the Sunlight Discount Factor to 1.
General Application & Usage Guidelines
• Auto Set-Point calibration is based on the assumption that the space was designed to be
adequately (100%) lit by the lighting controlled by the sensor. Rooms that are over or under lit by design may need to have the Set-Point adjusted.
• Occupants desiring more energy savings should decrease the Set-Point
(FN #8, Selection 1).
• The following table gives suggestions on how to fine tune sensors to occupants’
preferences.
@ Low Daylight Conditions @ High Daylight Conditions
Light Level
is too Low
Increase Set-Point
(FN#8, Setting 2)
Increase Sunlight Discount
Factor (FN#7)
Light Level
is too High
Decrease Set-Point
(FN#8, Setting 1)
Decrease Sunlight Discount
Factor (FN#7)
• If during Auto Set-Point calibration the sensor reads a level less than 4 fc, the set-point
will be defaulted to 4 fc.
• FN #5 and FN #6 can also be used to manually program the Set-Point value.
• For sensors used in open loop applications, running Auto Set-Point is not recommended.
• Sensors have dynamic cloud detection which prevents excessive cycling on cloudy days
by adjusting the time it takes before shutting lights off (5-25 minutes).
• Continuous rapid blinking from the sensor LED will occur before transitioning lights
On/Off due to daylight.
Sensor Switch, Inc.
900 Northrop Rd., Wallingford, CT 06492
(203) 265-2842 info@sensorswitch.com
www.sensorswitch.com
revised 06/12/2006
copyright Sensor Switch, Inc. 2006