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SIARETRON 1000 – 1100 - 3000
Service Manual
3.4
Operating principle
The lung ventilators of SIARETRON series are devices for assisted ventilation equipped with a microprocessor
control system composed of a 5 printed circuits kit; such a system controls the pneumatic circuit which delivers
the medical gas to the patient and permits to the operator the setting of operating parameters by a button panel
and a display.
The printed circuits composing the control system are:
Power supply (POWER)
•
cpu (LV200-MAIN/1)
•
panel and panel control (PANEL)
•
input/output (LV200I/O)
•
3.4.1 Hardware features
POWER (POWER SUPPLY)
Device power supply board. It controls three different power sources:
12 Vdc (external battery: it needs a "presence contact", or a staple closed between two clamps)
1.
12 Vac (secondary of a main powered transformer at 220V/50Hz)
2.
12 Vdc (rechargeable internal battery)
3.
Here below listed in decreasing priority order; on the board two 2,5A fuses are present on the inlets of the two
batteries, while the main inlet is protected by fuses on 220 V power line at the level of the main switch block.
In case of main power supply the board provide to recharging internal battery in a maximum of 10 hours; such a
recharging can be effected also when the machine is off, provided that main switch (on the rear side) is on.
The start-up of the machine (which is made by pressing the ON/OFF button on the front panel) and the choice
of power supply source are made by dedicate relay present on the board.
The board generates the following tensions:
+ 5 V / 1 A for the logic part of the system,
•
+ 8 V / 1,5 A for displays and panel leds powering;
•
20 V not stabilized for the polarization of analog electronic presents on LV200I/O board;
•
12 ÷ 15 V not stabilized (depends on which source is used) for powering of pneumatic circuit
•
electro valves, fan wheel, buzzer and relays.
The turn-on/off mechanism is effected by the circuit indicated in figure 1; with the ON/OFF switch of the panel
the two clamps get in contact the two CN2 connector clamps, starting up the Q3 transistor whom excites the K3
relay.
Hence, the Vcc tension is generated (through the 8301L stabilizer) whom supply the micro controller on
the CPU board, this generates by its side an high logic level (Vcc) on the line denominated AUTO_ON whom
maintains the K3 relay excited (and so all the device is powered).
The turn-off by ON/OFF switch is possible thanks to the Q5 transistor, through whom the micro controller knows
switch status, the software carries out the turn-off when it reads the pressed switch for more than one second,
generating a low logic level (0 V) on the AUTO_ON line and turning-off all peripheral devices (display and
electro valves). The machine remains, anyway, physically powered since the ON/OFF switch is released.
SIARETRON_SE3_en
9 / (72 )
( rev.3) 30.06.2004
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