Siemens SC 7000 Service Manual page 47

SC 7000 and SC 9000XL Patient Monitors
CURRENT LIMITED
4 VOLTS
S1L
CLAMP AND
FILTERING
1 2
NETWORKS
P
S2L
A
2 DIFFERENTIAL TO
1
P
4 TO 1 MULTIPLEXER
S3L
A
2
1
P
S4L
A
1 2
P
A
PRESSURE SENSORS
+4.0 VOLTS
LINEARIZE
FILTER AND
CLAMP
T
A
T
A
TEMPERATURE SENSORS
O.7R
R?
BLOOD TEMP
T
INJECTATE TEMP
T
A
Figure 2-16 HEMO 2/4 POD Functional Block Diagram
12.2.1 Temperature
ASK-T898-03-7600
7k9kXLTM.c2.CD_ROM.fm/04-99/kaupp
+5V OUTPUT
NON-ISOLATED
SWITCHING POWER
VOLTAGE
SUPPLY
A
REFERENCE
-5V OUTPUT
SINGLE-ENDED
CONVERTER AND
4PRESS
(USING FLYING
MUX
CAPACITOR
200 mmHg
TECHNIQUE)
0 mmHg
CALIBRATION CONSTANTS
VOLTAGE
REFERENCE
TA0 TA1
T1
OFFSET
FIXED GAIN OF 10
T37
+
MUX
T10
+
+5V MONITOR
T2 A
-5V MONITOR
OFFSET
+
+
MUX
R_EDWARDS
FIXED GAIN OF 20
GROUND
A
Figure 2-17 IBP Functional Block Diagram
Next, the signals enter a functional block that converts the differential
signals into single ended signals which are then presented one at a time in
a time-multiplexed fashion to a fixed gain single ended amplifier.
Calibration voltages for zero and 200 mmHg are periodically switched into
the amplifier input to correct errors in amplifier offset and gain respectively.
An A/D converter samples the resulting output voltage. Timing is
coordinated by the logic gate array.
Each of two thermistors is connected to a functional block that consists of
a precision resistor network to partially linearize the voltage verses
temperature transfer curve of the thermistor. This functional block also
consists of means for filtering RF noise and limiting the voltage swing. A 4.5
Volt reference is connected to power each linearization network.
Siemens Medical Systems, EM-PCS Danvers
NOT A CONTROLLED DOCUMENT
+12V INPUT
200KHZ SYNC SIGNAL
FIXED GAIN OF 311
A
DATA AND CONTROL
D
A
16 BIT
TCA0 TCA1
FIXED GAIN OF 2
MUX
A
Service Manual
ZERO
LCD
PUSH
BUTTONS CO START
WEDGE
LCD
CONTROLLER
LOGIC GATE ARRAY
DATA
CLOCK
MANCHESTER
DATA OUT
DATA TRANSMITTER
DATA RECEIVER
EEPROM
WRITE
PROTECTED
EEPROM
R/W
MANCHESTER
DATA IN
31