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System Control
System Control
System Control
System Control
LP6 Plus, LP10, and LP20 Technical Manual
November 2000
Page 4-15
Page 4-15
Page 4-15
Page 4-15
The charge path for the external battery is through diode CR8 on the
older through-hole board, or D37 on the newer surface-mount
board, and in the case of the internal battery, through CR7 on the
older through-hole board, or D36 on the newer surface-mount
board, and the relay contact.
The external battery is always on line. The internal battery is on line
for powering the system through a diode, and a relay contact (nor-
mally closed). The relay is powered on its positive side by the exter-
nal battery. If no external battery is connected, and if the charger is
not on, this relay cannot operate, so the internal battery will be on
line by default. The relay is also controlled on the negative side by
the microprocessor.
Because the system cannot differentiate between a fully charged
battery (internal and external) and no battery, the battery charge
circuitry is interrupted for three seconds every five minutes to allow
this check to be completed.
U4 on the older through-hole board, or U13 on the newer surface-
mount board, detects when system voltage has fallen below approxi-
mately 8V. At that point everything is cut off except the alarm. The
ventilator will not function with power this low, so the remaining
power is used to alert the caregiver of the conditions via the audible
and visible alarm system.
LED Board
The LED Board contains eight LEDs that are digitally powered by
the microprocessor. A ninth LED is powered by AC power but is read
by the microprocessor to determine the presence of the AC power
source. Two push button switches,
ALARM SILENCE/RESET
and
BATTERY
TEST
,
send inputs to the microprocessor when activated.
Содержание LP6 Plus
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