7
Design-in Guide - EasyAir SNS300
April 2019
X1
X2
Y1
Y2
H
Motion detector
The occupancy sensor is a PIR (Passive Infrared)
sensor that detects movement with an X-Y
cross-area under an angle of X = 72° and Y = 86°. Two
types of movements are defined in NEMA WD7 as
follows:
• Major movement: movement of a person walking
into or through an area.
• Minor movement: movement of a person sitting at
an office desk reaching for a telephone, turning the
pages in a book, opening a file folder, picking up a
coffee cup, etc.
When installed in a typical office ceiling at H, the
sensor is sensitive to minor movements within X1 by
Y1 area. It will respond to minor movements down to
a few centimeters at the task area of a desk and is
sensitive to major movements within a range of X2
by Y2. The maximum recommended height to place
the sensor in the ceiling is 10ft/3m to assure
movement coverage and detection. The PIR sensor
reacts on movement by means of a temperature
difference, such as the human body temperature
versus its surrounding temperature. A car that just
starts its engine is not seen by the PIR nor does the
PIR see people sitting within the car or a forklift truck.
Therefore, it is recommended not to use EasyAir
SNS300 in outdoor, parking or industrial
applications. Please refer to the EasyAir SNS300
datasheet for coverage area details.
Figure 1. Motion detection area. H: ceiling height. Minor movement detection area: X1 by Y1. Major movement detection area: X2 by Y2.
August, 2019
