3 Operation overview
SMARTS II
19
Alarm indication overview
3.3 Sensor
The SMARTS II detects all types of electric fields from 2 MHz to 100
GHz. The monitor uses a dual sensor design. The microwave portion of
each sensor employs thermocouple detectors so that radar signals are
accurately converted to true RMS values while the diode design used for
the lower frequencies provides RMS detection even in very complex,
multi-signal environments. The output of the high frequency sensors is
combined and fed to a low-noise amplifier circuit. Similarly, the output of
the low frequency sensors is combined and fed to another low-noise
amplifier.
The output of these two amplifier circuits is scaled in terms of percent of
the respective human safety standard. The sum of these two amplifier
levels is used to determine whether the monitor is above or below the
alarm threshold that has been selected by the user. SMARTS II respond
equally to all polarizations and cover an entire hemisphere.
3.4 Battery compartment
Removing the cover that is attached with four captive screws accesses
the battery compartment. The cover has an RFI (Radio Frequency
Interference) gasket to ensure that the internal circuits remain isolated
from strong electromagnetic fields.
The U9VL battery can be inserted in the battery compartment. The
BATT
–PS
(battery
–power supply) switch and a two-section
Alarm
Threshold
DIP switch are also located within the battery compartment.
Condition
Audible and visual alarm
indications
Status signal
Normal operation
LED flashes every 40 sec.
Low
Low battery
Alarm chirps and LED flashes every
40 sec.
Low
Test key depressed
Continuous sound, LED flashes
every sec
High
Alarm
Continuous sound, LED flashes
every sec
High
Disconnected
Sensor
Continuous sound, LED flashes
every sec
High
