Unihedron SQM-LU-DL, Operator'S Manual

Page: 21 / 101

5.2 Diagnostic LED
Current consumption values:
I
Q
= 209 uA Quiescent current (5.1)
I
W
= 10 mA Wake current (5.2)
I
M
= 55 mA Measure current (5.3)
Current consumption timing:
t
Q
= 1 − ( t
W
+ t
M
) (5.4)
t
W
=
3 s
60 s
(5.5)
t
M
=
5 s
n
×
60 s
(5.6)
n = number of minutes between samples (5.7)
Current consumption formula:
I
Avg
= t
Q
×
I
Q
+ t
W
×
I
W
+ t
M
×
I
M
(5.8)
Figure 5.3: Current profile
As an example for determining battery life of a 3AH battery with sampling every 5 minutes:
T
Batt
=
AH
Rating
I
Average
(5.9)
=
AH
Rating
( I
Q
×
t
Q
+ t
W
×
I
W
+ t
M
×
I
M
)
(5.10)
=
3 AH
(209 uA × 0 . 9 ˙3 +
3 s
60 s
× 10 mA +
5 s
5
×
60 s
× 55 mA )
(5.11)
= 1861 hrs, or 78 days, or 2.5 months (5.12)
Note that measuring is still performed for ”Threshold” settings, even when it is too bright to record a reading. Measuring
is performed to determine this ”measure” state, and I
M easure
still applies.
5.2 Diagnostic LED
When the unit is connected to a battery, the red LED near the USB connector will illuminate in the sequence shown in
Figure 5.4 (firmware feature version 26 onwards):
Unihedron SQM-LU-DL Operator’s Manual -
20220119
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