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Operation
The AirScan
iR has several modes of operation,
TM
including two normal run modes, two 4/20 mA loop
check modes and five calibration modes. These
will be explained in Operation, Section C, Modes of
Operation. Modes are entered by properly activating
pushbuttons located on the circuit board, shown in
Figure 4.
Sensor operation status is indicated by the blink
pattern of seven LED's located in a vertical row on the
right side of the sensor circuit board (see Figure 4).
LED status is differentiated by color and duration/
pattern of blink(s). LED Indicators and Blink
Sequences are shown in Figure 6, followed by an
explanation of blink patterns.
Start-Up Procedure
Before applying power, make a final check of all wiring
for continuity, shorts, grounds, etc. It is usually best
to disconnect external alarms and other equipment
from the sensor until the initial start-up procedures are
completed.
Check the power supply voltage to the sensor with
a digital volt meter set to VDC. Place the black lead
on sensor terminal GND and the red lead on +24 (see
Figure 4, Note 1). Voltage should be between 21 and
28 VDC. If voltage is outside this range, check power
supply and wiring.
After power-up, ensure the LED's below are
operational as follows (see Figure 3):
• Green "Power" LED continuous ON
• Both Fault LED's are OFF
• Green "source" LED is blinking once every 2
seconds
NOTE: For cold/humid adverse environmental
conditions the "ATMOS" LED may be turning on and
off periodically. In addition, the "system" LED may
be blinking or continuous ON, also described in later
sections.
IMPORTANT: The AirScan
calibrated and should require minimal adjustments
after installation.
CARB Compliance: To ensure continued compliance
with CARB performance guidelines, calibrate the unit
in the environment in which it will be used. Frequency
of calibration can improve accuracy; Honeywell
Analytics recommends calibration every 6 months.
iR sensor is factory
TM
AirScan iR - Industrial
Environmental factors such as temperature, humidity,
and pressure can affect accuracy. Consider these
factors when establishing a maintenance program .
Allow the sensor to operate for 12 hours with the
enclosure sealed prior to testing the sensors. This
will give the sensor time to reach thermal equilibrium
to the external and internal temperatures while in
operation. Because sensors are normally located at a
distance from the main unit, the test time required and
accuracy of the response checks will be improved if
two people perform the start-up procedures and use
radio contact.
Start-Up Test:
1. One person exposes each sensor to a small
amount of the gas that is being monitored.
2. The second person stays at the control unit to
determine that each sensor, when exposed to the
gas fumes, is connected to the proper input and
responds, causing appropriate alarm functions.
Figure 3. Required LED status at start-up
7
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