Campbell Scientific Power Supplies - Campbell CR510 Operator's Manual

SECTION 14. INSTALLATION AND MAINTENANCE
System operating time for the batteries can be
determined by dividing the battery capacity
(amp-hours) by the average system current
drain. The CR510 draws <1 mA in the
quiescent state, 13 mA while processing, and
46 mA during an analog measurement; the
length of operating time for each datalogger
instruction is listed in the programming section.
Typical current requirements for common
CR510 peripherals are given in Table 14.2-1.
14.3 CAMPBELL SCIENTIFIC POWER
SUPPLIES
CR510 Power Supplies are available from
Campbell Scientific with either alkaline or lead
acid batteries, the BPALK and PS12LA,
respectively. The PS512M is also a lead acid
supply with two 9-pin null modem ports for
communication modems, see Section 14.3.3.
The BPALK has 8 D cell alkaline batteries, the
PS12LA has a rechargeable lead acid battery.
The alkaline batteries are discarded after use.
The lead acid batteries should be float charged
with either AC power or a solar panel. The lead
acid battery supplies power during a power
failure or in times of low charge with a solar
panel.
The CH12R and CH512R contain the same
circuitry as the PS12LA and PS512M,
respectively. They are used to float charge an
external 12 VDC Yuasa battery using AC or
solar power. No internal batteries are contained
in the CH12R and CH512R. Their operation,
however, is identical to that of the PS12LA and
PS512M. Other power supply options are
connecting a 12 volt battery directly to the
CR510, Section 14.5, or supplying power from a
vehicle, Section 14.6.
14-2
The PS12LA Power Supply provides 12 volts,
regulates incoming AC or DC power, limits
current from the battery, and provides circuitry
to connect an external 12 volt battery.
Each of the power supplies has a thermal fuse
in the power circuit that limits source current. If
excessive current is drawn, the fuse gets hot,
increases in resistance, and limits current.
When the problem is fixed, the fuse cools and
the resistance decreases, eventually allowing
current to pass. When excessive current is
drawn due to shorting the power leads to the
Terminal Strip, allow 10 to 15 seconds for the
fuse to cool before connecting power.
14.3.1 BPALK ALKALINE POWER SUPPLY
The BPALK uses 8 alkaline D cells and comes
with an AA cell battery pack to supply power
while replacing the D cells. The 4 AA batteries
are not included (see Figure 14.3-1).
To replace the batteries without stopping the
datalogger program, 1) connect the external
battery to the port labeled temporary, 2) remove
the old batteries, 3) replace with new alkaline D
cell batteries, and 4) remove the external
battery.
A fresh set of eight alkaline D cells has 12.4
volts and a nominal rating of 7.5 amp-hours at
20 C. The amp-hour rating decreases with
temperature as shown in Table 14.3-1.
Datalogger Instruction 10 can be used to
monitor battery voltage. Replace the alkaline
cells before the CR510 battery voltage drops
below 9.6 V.