Service manual

4. BOARD/UNIT DESCRIPTION
Service Manual BSM-4100 4.13
The NIBP Measure board has the pressure sensor for NIBP measurement to detect
the cuff pressure and convert it to an electrical signal.
The NIBP Safety board consists of a microcontroller for safety control, pressure
sensor, solenoid valve, pump and power supply cut-off circuit for the valve and
pump. This board as well as the NIBP Measure board individually monitors the
cuff pressure. If a wrong operation such as excessive cuff inflation caused by the
NIBP Measure board occurs, the NIBP Safety board provides the multi safety
functions so that the patient is protected from the wrong operation.
When the microcontroller works for the safety, the drive voltage is not supplied to
the pump and valve for 30 seconds. This prevents the cuff from inflating during
this period.
Since the measurement data from the NIBP Measure board and NIBP Safety board
are compared and safety circuit operation is always monitored, the “Safety Circuit
Error” status message immediately appears on the screen if the NIBP measurement
has something wrong.
NIBP Measure Board and NIBP Safety Board
Hall
IC
NIBP
socket
ECG RESP 3
Exciter
+5 V
Pressure
sensor
Amp
offset
adj.
LPF
HPF
NIBP Measure board
LPF
DPU board
INST
Amp
Gain selector
Gain selector
MPX
250 Hz
125 Hz
Level
shift
LPF
NIBP
microcontroller
Pump and valve
power supply
Pump driver
Valve driver
Pump
Valve
NIBP Safety board
Exciter
+5 V
Pressure
sensor
+2.5 V