Datex-Ohmeda S-5 Service Manual M-P M-PT
S/5
Datex-Ohmeda Pressure Modules
TM
Pressure Temp Module, M-PT (Rev. 02)
S/5
TM
Pressure Module, M-P (Rev. 04)
Technical Reference Manual Slot
Datex-Ohmeda Inc.
3030 Ohmeda Drive
53707–7550 MADISON, WIS
USA
Tel. +1-608-221 1551, Fax +1-608-222 9147
www.us.datex-ohmeda.com
All specifications are subject to change without notice.
Document No. 800 1013-1
June 2001
Datex-Ohmeda Division,
Instrumentarium Corp.
P.O. Box 900, FIN-00031
DATEX-OHMEDA, FINLAND
Tel. +358 10 394 11 Fax +358 9 146 3310
www.datex-ohmeda.com
Instrumentarium Corp. All rights reserved.
Table of contents
TABLE OF CONTENTS
Pressure Module, M-P, Pressure Temp Module, M-PT
TABLE OF CONTENTS i
TABLE OF FIGURES ii
Introduction 1
1 Specifications 2
1.1 General specifications ..............................................................................................................................2
1.2 Typical performance .................................................................................................................................2
1.2.1 InvBP...............................................................................................................................................2
1.2.2 Temperature.....................................................................................................................................2
1.2.3 Signal output ...................................................................................................................................2
1.3 Technical specifications............................................................................................................................3
1.3.1 InvBP...............................................................................................................................................3
1.3.2 Temperature.....................................................................................................................................3
1.3.3 Signal output ...................................................................................................................................3
2 Functional Description 4
2.1 Measurement principle .............................................................................................................................4
2.1.1 Invasive blood pressure ....................................................................................................................4
2.1.2 Temperature.....................................................................................................................................4
2.2 Main components.....................................................................................................................................4
2.2.1 PT board ..........................................................................................................................................6
2.3 Connectors and signals...........................................................................................................................10
2.3.1 Module bus connector....................................................................................................................10
2.3.2 Front panel connectors...................................................................................................................11
2.3.3 Other connectors............................................................................................................................11
3 Service Procedures 13
3.1 General service information.....................................................................................................................13
3.2 Service check .........................................................................................................................................13
3.2.1 Recommended tools ......................................................................................................................13
3.3 Disassembly and reassembly..................................................................................................................18
3.4 Adjustments and calibrations..................................................................................................................19
3.4.1 Invasive pressure calibration...........................................................................................................19
3.4.2 Temperature calibration..................................................................................................................19
4 Troubleshooting 21
4.1 Troubleshooting chart .............................................................................................................................21
4.1.1 Invasive blood pressure ..................................................................................................................21
4.1.2 Temperature...................................................................................................................................22
Troubleshooting flowchart ..............................................................................................................................23
5Service Menu 24
5.1 P/PT menu .............................................................................................................................................25
5.2 P/PT calibration menu ............................................................................................................................26
6 Spare Parts 28
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Datex-Ohmeda S/5 monitors
6.1 Spare parts list.......................................................................................................................................28
6.1.1 Pressure Module, M-P, Rev. 00.......................................................................................................28
6.1.2 Pressure Module, M-P, Rev. 01.......................................................................................................29
6.1.3 Pressure Module, M-P, Rev. 02.......................................................................................................29
6.1.4 Pressure Module, M-P, Rev. 03.......................................................................................................29
6.1.5 Pressure Module, M-P, Rev. 04.......................................................................................................29
6.1.6 Pressure Temp Module, M-PT, Rev. 00 ............................................................................................30
6.1.7 Pressure Temp Module, M-PT, Rev. 01 ............................................................................................31
6.1.8 Pressure Temp Module, M-PT, Rev. 02 ............................................................................................31
6.1.9 Front panel stickers for AS/3 modules (square buttons)...................................................................31
6.1.10 Front panel stickers for S/5 modules (round buttons) .................................................................. 31
7 Earlier Revisions 33
APPENDIX A 35
Service check form A-1
TABLE OF FIGURES
Figure 1 Datex-Ohmeda M-PT and M-P Module...................................................................................................1
Figure 2 Front panel of M-P and M-PT Module..................................................................................................... 5
Figure 3 PT board block diagram ........................................................................................................................ 6
Figure 4 Pressure transducer principle of operation.............................................................................................7
Figure 5 Temperature measurement principle..................................................................................................... 8
Figure 6 Serial communication and opto isolation section................................................................................... 8
Figure 7 Module bus connector (X1) .................................................................................................................10
Figure 8 Troubleshooting flowchart...................................................................................................................23
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Document No. 8001013-1
INTRODUCTION
This section provides information for the maintenance and service of the Pressure Module, M-P,
and Pressure Temp Module, M-PT. The M-P and M-PT modules are single width plug-in modules
designed for use with the S/5 monitors. Both modules provide invasive pressure measurement.
Additionally, the M-PT-module provides temperature measurement. The M-PT module also has a
connector for direct ECG and pressure signal output.
NOTE: Do not use identical modules in the same monitoring system. The modules M-P and M-PT
are considered as identical modules.
Pressure Module, M-P and Pressure Temp Module, M-PT
Figure 1 Datex-Ohmeda M-PT and M-P Module
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Document No. 800 1013-1
Datex-Ohmeda S/5 monitors
1 SPECIFICATIONS
1.1 General specifications
Module size, W × D × H 37 × 180 × 112 mm / 1.5 × 7.1 × 4.4 in
Module weight 0.35 kg / 0.8 lbs
Power consumption Approximately 3.5 W
1.2 Typical performance
1.2.1 InvBP
Measurement range -40...+320 mmHg
Accuracy ±5 % or ±2 mmHg, whichever is greater
Zero adjustment range ±150 mmHg
Calibration range ±20 %
Scales Upper limit is adjustable between 10 and 300 mmHg in steps of
Sweep speed 12.5, 25, 50 mm/s
10. Lower limit is 10 % of selected upper limit below zero.
DIGITAL DISPLAY
Range -40...+320 mmHg
Resolution ±1 mmHg
WAVEFORM DISPLAY
Range -30...+300 mmHg
HEART RATE FROM ARTERIAL PRESSURE
Measurement range 30...250 bpm
Resolution 1 bpm
Accuracy ±5 bpm or ±5 %, whichever is greater
1.2.2 Temperature
Measurement range 10...45 °C (50...113 °F)
Display resolution 0.1 °C (0.1 °F)
Temperature test Automatic (every 10 min.)
YSI 400 probe compatible
1.2.3 Signal output
ECG out 1 V/mV
Pressure P3 out 1 V/100 mmHg, (0...300 mmHg)
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1.3 Technical specifications
1.3.1 InvBP
Accuracy ±5 % or ±2 mmHg, whichever is greater
Transducer and input sensitivity 5 µV/V/mmHg, 5 VDC, 20 mA max current
Nonlinearity <1 %, 0 to 200 mmHg
Filter 0...4 - 22 Hz adjustable
Zero set accuracy ±1 mmHg
Calibration resolution ±1 mmHg
Zero time less than 15 sec
Protection against electrical shock Type CF defibrillation proof
DIGITAL DISPLAY AVERAGING
Art and P1 digital displays are averaged over 5 seconds and updated at 5 seconds intervals. All
other pressures have respiration artifact rejection.
NOTE: The accuracy of the measurement may be different from that specified, depending on the
transducer/probe being used. Please check the transducer/probe specification.
Pressure Module, M-P and Pressure Temp Module, M-PT
<2 %, -40 to 0 and 200 to 320 mmHg
1.3.2 Temperature
Measurement accuracy ±0.1 °C (25.0...45.0 °C)
Protection against electrical shock Type CF
NOTE: The accuracy of the measurement may be different from the specified, depending on
transducer/probe used. Please check the transducer/probe specification.
1.3.3 Signal output
Max. delay: ECG1 15 ms
Pressure offset error max. 10 mmHg
±0.2 °C (10.0...24.9 °C)
Pressure P3 25 ms (0...300 mmHg)
Document No. 800 1013-1
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Datex-Ohmeda S/5 monitors
2 FUNCTIONAL DESCRIPTION
2.1 Measurement principle
2.1.1 Invasive blood pressure
To measure invasive blood pressure, a catheter is inserted into an artery or vein. The invasive
pressure setup, consisting of connecting tubing, pressure transducer, an intravenous bag of normal
saline all connected together by stopcocks, is attached to the catheter. The transducer is placed at
the same level with the heart, and is electrically zeroed.
The transducer is a piezo-resistive device that converts the pressure signal to a voltage. The monitor
interprets the voltage signal so that pressure data and pressure waveforms can be displayed.
2.1.2 Temperature
The temperature is measured by a probe whose resistance varies when the temperature changes,
called Negative Temperature Coefficient (NTC) resistor.
The resistance can be measured by two complementary methods:
• Applying a constant voltage across the resistor and measuring the current that flows through
it.
• Applying a constant current to flow through the resistor and measuring the voltage that is
generated across it.
In S/5 module the two methods are combined in a form of a voltage divider. The NTC-resistor is
connected in series with a normal resistor and a constant voltage is applied across them. The
temperature dependent voltage can be detected at the junction of the resistors, thus producing the
temperature signal from the patient. The signal is amplified by analog amplifiers and further
processed by digital electronics.
2.2 Main components
The M-PT module consists of the following main parts:
• PT board
• Two connectors for YSI 400 series temperature probes; temperature channels T3 and T4.
• Nicolay-type connector for an invasive blood pressure sensor; invasive blood pressure
channel P3.
• Key for pressure zeroing.
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Document No. 8001013-1
• DIN-type connector for two direct ECG output signals and pressure 3.
NOTE: These output-signals are non-floating
The M-P module consists of the following main parts:
• PT board
• Nicolay-type connector for an invasive blood pressure sensor; invasive blood pressure
channel P3.
Pressure Module, M-P and Pressure Temp Module, M-PT
• Key for pressure zeroing.
Communication between the module and the central unit is established through RS485 serial
interface.
The power supply voltages to the module are generated in the power supply section of the
monitor’s Central Unit. All electrical connections between the module and the Central Unit are
established via 25-pin D-type connector on the backside of the module.
Zero
P3
Signal
Out
P3
T3
T4
P3
Zero
P3
Figure 2 Front panel of M-P and M-PT Module
Document No. 800 1013-1
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Datex-Ohmeda S/5 monitors
A
2.2.1 PT board
Module bus connector, D25
RS485 driver
for data
Opto
Isolation
non-volatile
memory
RS485 driver
for module
reset
Patient Isolation
Microprocessor
section
Power-up
reset
ECG OUT
PRESSURE OUT
to output connector
/D converter
Power
,
non-isolated
section
Isolation
transformer
Power,
isolated
section
INV.pressure
measuring
unit
to pressure
sensor
Figure 3 PT board block diagram
ECG and pressure signal prosessing
The PT-module has the Signal Out connector, for output of analog ECG and pressure signals.
The analog ECG-output signals are made by detecting the pulse-width modulated (PWM) ECG
signal of the module bus. The module detects the presence of the pacemaker pulses by following
the ECG module. Every time the pacer pulse has been detected, the microprocessor of the M-PT
module generates a 2.5 ms pacer pulse which is added to the analog ECG signal.
The PRESSURE OUT signal is generated from the P3 invasive pressure signal of the M-PT module.
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Document No. 8001013-1
Temperature
measuring
unit
to temperature
sensors
Keyboard
The P3 signal is transmitted as a pulse width modulated (PWM) signal over the patient isolation.
The analog signal is generated by low-pass filtering the PWM signal.
Microprocessor unit
The microprocessor uses the Intel 80C196KC-16 which includes three A/D converters and a UART.
There are external memories, an 8-bit data bus, a 16 MHz oscillator, an open collector reset, and a
watchdog timer. The internal UART communicates and transfers data between the module and the
CPU board in the monitor.
High speed I/O is used to obtain pulse control sequence necessary for pulse oximetry
measurement. It receives its timing clock from the oscillator.
Invasive blood pressure measurement unit
An isolated +5 V supply is connected to the input of the pressure transducer bridge circuit. From
the bridge circuit output a differential voltage, which depends on blood pressure and input supply
voltage, is calculated using the following formula:
Uout = Uin × Pressure × 5 V
Pressure Module, M-P and Pressure Temp Module, M-PT
where Uin = 5 V
Uout = 25 V × Pressure [mmHg]
Pressure amplification is performed by the instrumentation amplifier. The gain of the amplifier is
set so that the level of the signal transferred to the A/D converter stays within the measurement
range even when there are circumstantial offsets or offsets caused by the pressure transducer. The
input filter before the amplifier attenuates high frequency disturbances.
Vin
Pressure
transducer
Vout
Input
Filter
Instrumentation
amplifier
G
to AD converter
Figure 4 Pressure transducer principle of operation
Temperature measurement unit
Value of NTC-resistor in the probe depends on patient’s temperature. It is measured with the
following principle.
The temperature signal(s) is produced by voltage dividers, part of which is the patient probe (YSI
400-series thermistor). The output is amplified by the calibrated amplifier(s) whose offset voltage
makes its output spread on both sides of zero. Wider output range (measurement range) means
better resolution.
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Document No. 800 1013-1
Datex-Ohmeda S/5 monitors
0 °C => 7K357
15 °C => 3K541
25 °C => 2K253
38 °C => 1K301
45 °C => 984R1
NTC
Figure 5 Temperature measurement principle
Serial communication
Serial communication between the module and the Central Unit is done by RS485 type bus whose
buffers get their supply voltage (+5 VDC) from the Central Unit and in the isolation section get the
supply voltage (+5 V) from the isolated power supply.
The communication drivers are controlled by a reset signal such that when the reset is active the
drivers do not transfer data.
Reset is also RS485 type and additionally, there is an auxiliary logic power reset, which keeps the
reset active for about 500 ms despite the state of reset in the module bus. A time constant
determines the power-up reset time. There are components to prevent the module from sending
data during reset. The data transmission rate is 500 kbps.
+5Vreference
A1
to AD
converter
offset
Isolated section
r
o
Receive data
sess
o
r
send
p
e
Send
/receive
dat
Reset
a
Opto isolation
Receive data
Send data
Reset
RS485
Driver
send/r
RS485
Driver
Data
NDa
eceive
Reset in
NReset in
)
nit
s
t
a
u
l
ra
bu
e
nt
ce
to
(modul
to modul
Patient
Isolation
Figure 6 Serial communication and opto isolation section
There are two opto isolators, one for data and one for the reset signal. Signals are processed on
logical high-low levels even though the output of the opto isolators in the isolation section are
analog signals.
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Document No. 8001013-1
The reset line is an open collector type with a pull-up resistor so that the microprocessor is able to
use its internal watchdog 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. The transformer secondary circuit uses normal
linear regulators except for +5 V which uses a low drop type linear regulator.
Pressure Module, M-P and Pressure Temp Module, M-PT
Document No. 800 1013-1
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