Siemens Servo Ventilator 300, Service Manual

Page: 76 / 131

74 Siemens-Elema AB E382 E380E 061 01 03 01
Description of functions Servo Ventilator 300/300A
2
16 Expiratory valve
The function of this main block is to
squeeze the 14.5
EXPIRATORY VALVE TUBE
in a
regulated way.
16.1 Current control
Consists of the board PC 1585
CURRENT
CONTROL
.
Controller block regulating the current going
to the block 16.3
EXPIRATORY SOLENOID WITH
POSITION SENSOR
according to the desired input
signal
EXP
.
VALVE CURRENT REF
from the block
15.2
POSITION PD CONTROL
. The actuating
output signal is a pulse train with constant
frequency of 30 kHz and pulse width
modulation used in the block 16.2
CURRENT
POWER
.
16.2 Current power
Consists of the board PC 1586
CURRENT
POWER
.
Driving stage for the energy going to the
block 16.3
EXPIRATORY SOLENOID WITH POSITION
SENSOR
. The result of the output signal is a
certain opening of the
EXPIRATORY VALVE
.
16.3 Expiratory solenoid with
position sensor
The
EXPIRATORY SOLENOID
controls the opening
through the 14
EXPIRATORY CHANNEL
by
squeezing the 14.5
EXPIRATORY VALVE TUBE
to
desired position.
The solenoid receives power from the block
16.2
CURRENT POWER
. The power supply to the
solenoid is regulated so that the remaining
pressure in the patient system towards the
end of the expiration time is kept on the
PEEP level according to front panel setting.
An optical sensor on the board PC 1594
POSITION SENSOR E
mounted at the bottom of
the expiratory solenoid detects its position
and the resulting
EXP
.
VALVE POSITION
signal is
used in the block 15.2
POSITION PD CONTROL
.
Offset zeroing for the
EXP
.
VALVE POSITION
signal is controlled from the 6.1
MODE CPU
via
the block 15.4
VALVE ZEROING
.
17 Optional interface
Not used in this version.