Service manual

64 Siemens-Elema AB E382 E380E 061 01 03 01
Description of functions Servo Ventilator 300/300A
2
8.10 Pressure amplifier
The PRESSURE AMPLIFIER amplifies the input
signal from 8.4 SUPPLY PRESSURE TRANSDUCER.
The output signal from this amplifier,
representing the relative gas supply
pressure, is used in:
• 8.11 PRESSURE CALCULATOR to calculate the
absolute pressure of the gas
• 8.12 SUPPLY PRESSURE AMPLIFIER.
8.11 Pressure calculator
The PRESSURE CALCULATOR calculates the sum
of:
• Gas pressure (input from 8.10 PRESSURE
AMPLIFIER
) and
• Barometer pressure (input from 4.6
BAROMETER PRESSURE TRANSDUCER).
The result of this calculation is the absolute
pressure of the gas.
Output signals from the pressure calculator
are used in:
• 8.15 FLOW CALCULATOR
• 8.18 VALVE POSITION CALCULATOR.
8.12 Supply pressure amplifier
The relative gas supply pressure, input signal
from 8.10 PRESSURE AMPLIFIER, is amplified in
the SUPPLY PRESSURE AMPLIFIER.
Output signals from this block is used in:
•4 MONITORINGto show the corresponding
relative gas supply pressure on the front
panel
• 8.13 DELTA PRESSURE AMPLIFIER.
8.13 Delta pressure amplifier
The input signal from 8.5 DELTA PRESSURE
TRANSDUCER
is amplified in the DELTA PRESSURE
AMPLIFIER
. The output signal is influenced by
the relative gas supply pressure value from
8.12 SUPPLY PRESSURE AMPLIFIER as well as from
8.3 INSPIRATORY VALVE TEMPERATURE SENSOR.
The potentiometer at the top of the
INSPIRATORY VALVE UNIT implies a limited
(approx. ± 3%) adjustment possibility of this
signal. This signal is not a directly
proportional part of the flow and no service
adjustment must be made. If the INSPIRATORY
VALVE
UNIT proves to be out of specification it
is recommended -for safety reason- to
exchange it.
The output signal is used in 8.15 FLOW
CALCULATOR
.
8.14 Zero offset
The possible offset of the pressure drop
signal, measured by 8.5 DELTA PRESSURE
TRANSDUCER
, is set to zero in the beginning of
each breath cycle, i. e. when the flow
through the inspiratory valve is zero.
The block ZERO OFFSET deliveres an offset
compensation voltage to 8.13 DELTA PRESSURE
AMPLIFIER
. The zeroing function is controlled
from 15.4 VALVE ZEROING.