Datex-Ohmeda S/5 M-NE12STPR, Техническое описание слота

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S/5 Hemodynamic modules
Document No. 800 1008-2
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RS485
Driver
RS485
Driver
Reset
Send data
Receive data
send/receive
Receive data
Send data
send/receive
Reset
Opto isolation
Receive data
Send data
send/receive
Reset
Opto isolation
STP Board
ECG Board
Data
NData
Reset in
NReset in
Receive dat
Send data
send/receive
Reset
modu
le
processor
P
a
tient
is
ol
ati
o
n
connect
o
r for E
C
G board
C
onnector
for E
C
G board
modul
e bus
connector
m
odul
e processor
P
a
tient
is
ol
ati
o
n
C
onnect
o
r for S
T
P
board
Figure 13 Serial communication and opto isolation of M-ESTPR
Isolated section
There are two opto isolators. Signal is processed on logical high-low level even though the outputs
of the opto isolators are analog signals in the isolated section.
Reset line is an open collector type with a pull-up resistor. Thus the processor is able to use its
internal watch-dog function.
Power supply section
Isolated supply voltage of the module is developed from +15 Vdirty voltage from the Central Unit.
Power supply is a switched-mode circuit, where FET transistor switch is controlled by an oscillator
using bipolar timer. The frequency of the oscillator is about 30 kHz and pulse ratio 50 %.
Controlling of the FET switch is slowed to suppress spurious interference.
A special pulse transformer is used in the circuit. In the secondary circuit normal linear regulators
are used except for +5 V (low drop type linear regulator).