Campbell RF400, Instruction Manual

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Appendix L. RF400/RF410 Average Current Drain Calculations
L-3
EXAMPLE #1 (Remote RF400/RF410 in default standby mode)
There is a Point-to-Point system with base RF400/RF410 and remote
RF400/RF410. The
remote station senses weather conditions and sends low-
resolution data to final storage. The base station collects 10 data points from
the remote station once per minute. Both stations are configured for “<4 mA,
½ sec Cycle” (the default standby mode). The remote station operates on solar
power and we are interested in knowing the average current drain contribution
of the RF400/RF410. From the above section:
It = Is + Id + Ir + Ii
Calculating each term:
Is = table mA value = 4 mA
It
≈
6.1 mA
The dominant average current drain contributors are the standby mode current
and the “time of inactivity to sleep” currents. If large quantities of data per
minute were being generated/collected, then Id would become a significant
contributor. In this example the “time of inactivity to sleep” could be reduced
because only 10 data points are sent per collection. Try a value of 10 instead
of 50 reducing the Ii contribution from 2 mA to 0.4 mA.
mA 0.08 mA 73
ms 60,000
ms 65
mA 73
(ms) T
(ms)] N 2 (ms) 45 [
Id
= × = ×
+
=
mA 0.008 mA 24
(ms) 60,000
(ms) 20
Ir
= × =
mA 2 mA 24
(ms) 60,000
ms 5000
Ii
= × =