B30 Patient Monitor
1-40
Document no. 2044677-001
Figure 24 Serial communication of E-PSM(P)W module
Signals and isolation barrier
The communication signals transfer over the isolation barrier by using high isolation voltage
(6kV) opto isolators.
Power supply section
The power for the electronics on the floating part of the STP and the ECG boards is made on
each board with the switching power supplies connected to a high voltage isolated
transformer. The switching power supplies on the STP and ECG boards are synchronized to the
frequency, about 340kHz of the switching power supply on the NIBP board. The NIBP board
supplies non-isolated 5 V to the ECG and STP boards. The module uses only Vmod 13.8 - 16 V
voltage of the frame. The other voltages of the measuring boards are made by the switching
power supplies and regulators or the linear regulators. Each measuring board is protected
against overloading with PTC type automatic fuses.
RS 485
DRIVER
DATA
NDATA
RECEIVE DATA
SEND DATA
SEND/RECEIVE
N
I
B
P
B
O
A
R
D
C
O
N
T
R
O
L
L
E
R
S
NIBP BOARD
RS 485
DRIVER
S
T
P
B
O
A
R
D
C
O
N
N
E
C
T
O
R
RECEIVE DATA
SEND DATA
SEND/RECEIVE
S
T
P
B
O
A
R
D
C
O
N
T
R
O
L
L
E
R
STP BOARD
PATIENT ISOLATION
RS 485
DRIVER
E
C
G
B
O
A
R
D
C
O
N
N
E
C
T
O
R
DATA
NDATA
E
C
G
B
O
A
R
D
C
O
N
T
R
O
L
L
E
R
ECG BOARD
PATIENT ISOLATION
DIRECT ECG (PWM)
PSM_serial_communication.vsd
Module bus connector
DATA
NDATA
synchronization signal
+5 V
+5 V
+5 V
RECEIVE DATA
SEND DATA
SEND/RECEIVE
NIBP BOARD CONNECTOR