16
ObservAir
Operating Manual
LED Flash Pattern
Sensor Function
1x Blue
Menu enter feedback
1x Green
Reset attenuation
1x Red
Power off
1x Blue
Reserved for future features
2x Blue
Provision WiFi settings
2x Purple
Firmware update mode
Table 5.
Index of menu items displayed when holding down the LED
button. The LED display will cycle through the options in the order listed
until the button is released at the desired selection.
3.2.4.
Attenuation reset
Optical attenuation (ATN) represents the filter’s BC loading. By definition, a
clean filter tab (devoid of any BC) has an ATN of exactly 0. However, since
the optical depth of each filter intrinsically varies, the light intensity
transmitted through the active and reference filters on the tab are not
always equal, and the apparent ATN through the clean filter is therefore not
equal to zero, as desired.
The ObservAir automatically detects when the filter tab has been
changed, measures the apparent ATN, and offsets the ATN data by this
value such that ATN = 0 when the filter is clean. If the sensor does not
automatically detect the filter change for any reason, the ATN can be
manually reset by holding the LED button until the first green flash and
releasing. The LED will flash green twice more to confirm the selection, and
the ATN will be set to zero for the current light intensity values.
3.2.5.
Sensor shutdown
To turn off the ObservAir, hold the LED button to cycle through the menu
until the first red flash and release. The sensor will flash red two more times
to confirm that it is shutting down.
3.2.6.
Sensor alarms and errors
When a measurement error occurs or an alarm is triggered, the LED button
continuously flashes red or yellow. The speed and color of the flashing LED
denotes different error codes. If the ObservAir displays an error, refer to
Section 5 for troubleshooting instructions to diagnose and resolve the issue.
H
ol
d
L
E
D
b
u
tt
on
:
Op
ti
o
n
s
a
p
p
e
a
r
in
o
rd
e
r.
Re
le
a
s
e
fo
r
m
e
n
u
s
e
le
c
ti
o
n
.
17
ObservAir
®
Operating Manual
3.3.
Filter tab replacement
To change the filter tab, first release the thumbscrew by turning it
counterclockwise for about four full turns (Figure 8). Remove the filter tab
by pulling is straight out from the front of the sensor. The filter tab should
release from the sensor with little resistance. If there is any resistance,
further loosen and/or push down lightly on the thumbscrew to release the
filter tab. Second, insert a new filter tab with the notch aligned to the solid
white circle on the faceplate, as shown in Figure 9. Third, insert the new
filter as far as possible, such that the tip of the notch is flush to the front
panel, and hand tighten the thumbscrew firmly.
Figure 8.
Step 1 of filter tab replacement: Loosen thumbscrew and
remove the filter tab
Figure 9.
Step 2 of filter tab replacement: Insert a clean filter into the
sensor. Align filter notch with the solid white circle on the front panel.
Filter
Align filters/notch on tab with
solid white mark
Notch