Campbell CR300 series - Power LED Indicator; Calculating Power Consumption; Power out; Power LED Activity

CR300-Series Datalogger
40
USB port — 5 Vdc via USB connection. If power is also provided with BAT
or CHG, power will be supplied by whichever has the highest voltage. If USB
is the only power source, then SW12V will not be operational. Functions that
will be active with a 5 Vdc source include sending programs, adjusting
datalogger settings, and making some measurements. The excitation range of
VX1 and VX2 is reduced to 150 to 2500 mV. Control ports output 4.75 V, 8
mA maximum.
The CR300 is internally protected against accidental polarity reversal on the
power terminals. Sustained input voltages in excess of 17 V at the BAT
terminals or 33 V at the CHG terminals can damage the CR300.
6.7.1.2 Power LED Indicator
When the CR300 is powered, the red Power LED will turn on according to
power and program states. See TABLE 6-4.
TABLE 6-4. Power LED Activity
LED State Power State Program State
Off No power Not running
1 flash every 10 seconds Powered Running
3 flashes every 10 seconds Powered via USB Running
Always On Powered Not running
6.7.1.3 Calculating Power Consumption
In low-power situations, the CR300 can operate for several months on non-
rechargeable batteries. Power systems for longer-term remote applications
typically consist of a charging source, a charge controller, and a rechargeable
battery. When ac line power is available, a Vac-to-Vdc wall adapter, the on-
board charging regulator, and a rechargeable battery can be used to construct
an uninterruptible power supply (UPS).
When designing a power supply, consider the worst-case power requirements
and environmental extremes. For example, the power requirement of a weather
station may be substantially higher during extreme cold, while at the same
time, the extreme cold constricts the power available from the power supply.
System operating time for batteries can be determined by dividing the battery
capacity (ampere-hours) by the average system current drain (amperes). The
CR300 typically has a quiescent current drain of 1.5 mA and a current drain of
5 mA when running a 1 Hz scan with analog measurements.
Refer to the application note Power Supplies and the video Power Budgeting,
available at www.campbellsci.com, for more help in selecting a power supply.
6.7.2 Power Out
The CR300 includes many terminals to supply voltage and control for sensors
and devices.
• 150 to 5000 mV output — VX terminals supply 150 to 5000 mV. They
source 50 mA each, or 50 mA combined when used concurrently.