Campbell Scientific CR7 Measurement and Control System - Manual (Page 146)

SECTION 14. INSTALLATION
14-2
tight seal but do require protection from thermal
gradients when used for thermocouple lead
wires (Section 13.4).
14.2 SYSTEM POWER REQUIREMENTS
AND OPTIONS
The standard CR7 is equipped with sealed lead
acid battery packs and charging circuitry for
accommodating (1) 120/240 VAC line power,
(2) solar panels, (3) vehicular 12V power
sources, and (4) external 12V batteries. When
fully charged, the internal batteries of the CR7
are capable of providing 2.5 Amp-Hours of
service or about 5 days of operation in a typical
application where the CR7 is active 10% of the
time.
14.2.1 POWER SUPPLY AND AC CHARGER
Power for charging the internal batteries from
an external AC source is provided to the CR7's
12V charging regulator circuit board through the
power input connector located on the outside of
the case to the right of the Control Module.
The LABORATORY ENCLOSURE has a 4-
position voltage select (100, 120, 220 or 240)
insert chip and 0.1 amp slow blow fuse located
next to the power input connector (on the
outside of the enclosure). CR7s leave the
Factory with the voltage insert chip set to 120
VAC. If the intended line voltage is not 120V,
reposition the chip to correspond as closely as
possible with the AC line voltage available (the
number showing when the chip is inserted
specifies the voltage level).
ENVIRONMENTAL ENCLOSURES are
equipped with a weather-tight bayonet mount 3-
pin circular power connector. Access to the 2-
position (115 and 230) voltage select switch and
0.1 amp slow blow fuse is by lifting up the
Control Module Panel. The switch is set to 115
VAC at the factory.
A temperature compensated 12V CHARGING
REGULATOR CIRCUIT BOARD beneath the
Control Module regulates the charging voltage
supplied to the lead acid batteries and the
voltage to the CR7 operating system. DC
Power sources are connected to the terminal
block on the charging regulator board. The
terminals labeled "EXT BATT" are for
connecting a 12V power source. The terminals
labeled "SOLAR" are for connecting a solar
panel or DC source with sufficient voltage (15-
25 VDC) to charge the internal lead acid
batteries.
The LED auxiliary power light located on the
face of the Control Module, is activated by the
charging regulator when solar or AC charging
circuitry are connected to the CR7. The LED
operates with the ON/OFF switch in either
position but is NOT designed to operate when
an external 12V battery only is connected to the
CR7.
Power to the CR7 operating system is
controlled by the position of the ON/OFF toggle
switch located on the face of the Control
Module.
The sealed lead acid battery packs, located
below the Control Module, are rated at 6V each
and are connected in series to provide 12 VDC.
TABLE 11.2-1. CR7 Battery and Charging
Circuitry Specifications
BATTERY Type Gates #810-0011X
Float Life @ 25 oC 8 yrs minimum
Amp Hour Rating 2.5 amp-hour
Open Circuit Voltage 12.95 typ. with
@ Full Charge charging circuitry
deactivated, 14.1
@ 25 oC when
activated
Open Circuit Voltage 11.76 VDC
@ Full (SAFE) Discharge minimum
Shelf Life, Full Charge Check twice yearly
Charging Time from Full 40 hrs for full
Discharge (AC Source) charge, 20 hrs for
95% full charge
Charging Circuit Float charge with
temperature
compensated
voltage regulation
AC Line Filter (LAB.) 6 amp max, 48-440
Hz, 250 VAC max.
AC Line Filter (ENVIR.) 1 amp max, 50-60
Hz, 250 VAC max.
Power Supply Transformer 6 watt output