Siemens Servo Ventilator 300, Service Manual

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54 Siemens-Elema AB E382 E380E 061 01 03 01
Description of functions Servo Ventilator 300/300A
2
time and that period is used for this offset
zeroing.
Additionally, timing control of the offset
zeroing for the position signal within the
block 16.3
EXPIRATORY SOLENOID WITH POSITION
SENSOR
is generated and transferred via the
block 15.4
VALVE ZEROING
during
INSPIRATION
TIME
. The main block 16
EXPIRATORY VALVE
(regulation of opening) is enabled during
expiration time.
6.1.2. Respiratory timing
Timing is defined by the internal respiratory
phase control signals for
INSP TIME
and
PAUSE
TIME
and
EXP TIME
which are generated in this
block. When the Mode selector is in any
other position than Ventilator off or Stand by
one of these three control signals is always
active (HI), only one at a time.
PAUSE TIME
is
in use only if any of the Front panel
functions Pause time % or Pause hold is
active. Three LEDs at the top end of the PC
1605 marked
INSP
,
PAUSE
and
EXP
are used to
indicate the current respiratory phase.
During controlled ventilation, as well as for
mandatory breaths, the respiratory phase
control signals are related to the front panel
settings Insp. time % and Pause time %
and to the internal respiratory
CLOCK
signal
which has a frequency defined by the front
panel setting CMV frequency.
During SIMV modes the Front panel setting
SIMV frequency is in use. The SIMV
frequency defines the duration of the SIMV
cycle. The first part of each SIMV cycle is a
waiting period referred to as the SIMV
period. The duration of the SIMV period is
defined by the front panel setting CMV
frequency.
The
INSP TIME
signal is also used in the main
block 18
EXPIRATORY FLOW LINEARIZATION
for
zeroing of the
EXPIRATORY FLOW TRANSDUCER
signal in the block 18.3
ZERO OFFSET
.
Additionally, timing control of the offset
zeroing for the inspiratory flow regulation
within each
INSPIRATORY VALVE UNIT
is
generated and transferred via the blocks
15.4
VALVE ZEROING
and 15.5
VALVE ENABLING
.
Thus the inspiratory valves are enabled
during inspiration time and (for the constant
flow) during expiration time with the
following exception. This offset zeroing
takes place during each pause time if pause
time is available. When pause time is not
applied the enabling of the inspiratory valves
excludes the first 40 ms of each expiration
Timing conditions
Definition of parameters:
P
E
=
EXP
.
PRESSURE
P
I
=
INSP
.
PRESSURE
The internal respiratory
CLOCK
signal is a
pulse train with the Clock frequency =
= 100 x Preset CMV frequency
Clock cycle = (Clock frequency) -1
Duration of SIMV PERIOD =
= 90 x Clock cycle
Breath cycle = (Preset CMV frequency)
-1
=
= 100 x Clock cycle
SIMV cycle = (Preset SIMV frequency) -1
Numeric calculation note:
Cycle in seconds = 60 x Cycle in minutes