Vaisala CT25K - Page 82

Ceilometer CT25K
User’s Guide CT25K-U059en-2.1
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All these voltages are normally supplied by two 18VAC windings. The second
supply rectified from two 10VAC windings is reserved for internal battery
charger, heating power for transmitter and inheater and outheater control
relays.
All voltage and two temperature channel measurements along with several
internal and external functions are controlled by a two-wire serial I
2
C bus.
Identification and other board specific parameters are also saved in EEPROM
via this bus.
The internal battery charger keeps the sealed lead acid battery in maximum
charge and ready for power back-up. The battery is charged in four phases or
states:
- trickle charge, while battery voltage is below normal
- bulk charge, while battery is charged with maximum current
- over charge, while battery voltage is raised over its temperature
compensated level
- float charge, charge is complete and battery voltage is floating at the
temperature compensated level
LED functions
Two LEDs are located in the upper part of the front panel:
POWER OK LED (D2) is lit when battery circuit is connected and
charge is at least in bulk charge state and all voltages are ok.
ACCESS LED (D1) is lit every two seconds indicating a voltage
channel read cycle.
Internal switch settings
The following table describes the internal switch settings of DPS52. For
normal operation all switches shall be OFF.
Switch
position
Switch
setting
Function
s/w controlled
Switch
setting
Function
manual
S1/1 OFF not used ON not used
S1/2 OFF digital/analog voltages ON ON digital/analog voltages OFF
S1/3 OFF +/-5Vvoltages ON ON +/-5Vvoltages OFF
S1/4 OFF receiver voltages OFF ON receiver voltages ON
Specifications
Input voltages:
Power Inputs: Voltage ranges:
I (AC): 10 .. 22VAC
I (DC): 11.5 .. 30VDC
II (AC): 9 .. 12VAC
II (DC): 9 .. 16VDC