Smiths Medical Medfusion 3000 Series, Техническое и сервисное руководство

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Theory of Operation
39 40-5648-51B
The audio buzzer is enabled when the pump is turned
on, and when the watchdog_alarm signal activates.
The watchdog_alarm signal (from the auxiliary
controller) activates anytime there is a malfunction of
the main microprocessor. The main microprocessor
can activate this buzzer indirectly by not providing
the pet_watchdog strobe to the auxiliary controller
which causes a watchdog alarm.
• During power-up, the buzzer is tested by the
watchdog alarm state being active, and the buzzer
response verified through the buzzer_detect
signal.
System reset, U43
On startup, the microprocessor comes out of reset
when the logic supply exceeds 4.6 volts plus the built-
in delay of the reset IC.
Power management, U39
An embedded Auxiliary controller oversees the power
control management, and serves as the main micro -
processor watchdog. The behavior of the power man -
agement system depends on pump states:
•
Power Off
• Power On
• Watchdog Alarm
• and a Battery Disconnect .
Power OFF state
You must press, hold, and release the power switch
to turn OFF the power. In normal operation, both
the auxiliary controller and the main microprocessor
control power-off.
Power ON state
To enter the
power on
state the power_enbl signal
is initially set active by the auxiliary controller. This
requires the auxiliary controller provide an AC strobe
to the power_enbl circuit. This power_enbl signal
also arms the backup audio buzzer. The power_enbl
signal is verified by the main microprocessor monitor -
ing the buzzer_armed signal.
Watchdog
During a watchdog alarm, the auxiliary controller has
sole control of power-off.