Service manual

Servo Ventilator 300/300A Description of functions
E382 E380E 061 01 03 01 Siemens-Elema AB 45
2
4.2 Inputs interface & A/D
Multiplexor and analog to digital conversion
stages for input signals to the main block
4 MONITORING.
4.3 Sound & Alarm control
Alarm control circuits including the driving
stage for the block 4.7 LOUDSPEAKER.
4.4 Flow filters & Integrators
The input signals AIR FLOW and O
2
FLOW are
added to generate INSP. FLOW (block internal
signal INSP. FLOW SUM).
The difference between the signals INSP.
FLOW SUM and EXP. FLOW generates the signal
AIRWAY FLOW (= block internal signal EXP. FLOW
INT
.) as well as the signals INSP. FLOW PATIENT
and EXP. FLOW PATIENT. This way of calculating
is necessary to achieve the last two
mentioned signals of patient flow during
EXPIRATION TIME when a constant flow to the
patient system is generated via the
inspiratory valve(valves).
Integration during each breath of the signal
INSP. FLOW SUM generates INSP. TIDAL VOL. The
signal INSP. FLOW PATIENT is averaged to
generate INSP. MIN. VOL.
Integration during each breath of the signal
EXP. FLOW INT. generates EXP. TIDAL VOL. The
signal EXP. FLOW PATIENT is averaged to
generate EXP. MIN. VOL.
Some of the signals are used for monitor/
alarm within this main block, some of them
used for mode regulation algorithms by the
block 6.1 MODE CPU and some of them
displayed on the front panel. The signals
INSP. FLOW PATIENT and EXP. FLOW PATIENT are
available at the 3.6 ANALOG I/O TERMINAL.
4.5 Backup alarm system
The internal power supply voltages are
monitored in this block. If any of the voltage
limits are exceeded, the supply voltage alarm
is activated by the signal POWER_FAILURE.H.
The parameters AIRWAY PRESSURE (upper alarm
limit) and O
2
CONC and EXP. MINUTE VOLUME are
monitored (analog monitoring) at somewhat
wider alarm limits than the corresponding
digital monitoring function of the block 4.1
MONITOR/ALARM CPU. This block activates an
alarm only if the regular (digital) alarm
system is failing.
This block includes the driving stage for the
block 4.8 BEEPER.
Active backup alarm consists of intermittent
(in some case continuos) audible alarm
generated by means of the 4.8 BEEPER.
Preconditions for backup alarm: Alarm
condition mentioned below is fullfilled and
normal (digital control) alarm is not active. In
this connection the normal alarm is
considered not active also in case of
loudspeaker error (indicated via the Loud-
speaker supervisor function connected to
the Sound generation function in the block
4.3 SOUND & ALARM CONTROL).
Special condition leading to active Backup
alarm is mentioned under 4.1 MONITOR/ALARM
CPU
.
The Backup alarm system contains the
following different PMA = Parameter Monitored
for Alarm. Each alarm table contains
conditions for alarm.