Campbell Scientific AP200 CO2/H2O Atmospheric Profile System - Manual (Page 44)

AP200 CO
2
/H
2
O Atmospheric Profile System
TABLE 5-1. Equivalent Resistance for Intake Heaters
Connected in Parallel
Number Of
Heaters
Nominal Resistance
(ohms)
Acceptable Range
(ohms)
4 140 133 to 147
5 112 106 to 118
6 93 88 to 98
7 80 76 to 84
8 70 66 to 74
5.3.3 Power
The AP200 requires a 10 Vdc to 16 Vdc power source. The average power
consumption varies with ambient temperature, mostly due to the heater in the
IRGA that maintains its sample cell at 50°C. There are also heaters and fans
that will cycle on and off to maintain the temperatures of the pump and the
valve manifold. The maximum power consumption may briefly be as high as
45 W if the system is started at cold temperatures (below 0°C).
Carefully design any DC power source to ensure
uninterrupted power. Contact a Campbell Scientific
applications engineer for assistance if needed.
The AP200 can be damaged by pulling unfiltered air into
the valve manifold. Before applying power to the AP200,
make sure each inlet has a filter (such as included in the
AP200 intake assemblies) or is capped.
To reduce the risk of shorting the power supply (this is
especially important when using batteries), connect the
power cable to the AP200 first and then connect the other
end to the power source.
Insert the power cable, CABLEPCBL-L, through the feedthrough and connect
it to the DIN rail bus in the system enclosure. The red, positive wire connects
to one of the terminals labeled 10 to 16 Vdc In. Connect the black, negative
wire to one of the terminals labeled G as shown in FIGURE 5-17. Two
connections are provided for convenience if multiple power sources are to be
connected (for example, two batteries, or a battery and an AC/DC power
adapter).
Each of these two power connections has a diode to prevent
reverse current flow. This allows two batteries to be connected
safely to the AP200 even if one is fully charged and the other is
discharged.
CAUTION
NOTE
32