Datex-Ohmeda S-5 Service Manual M-NE12STPR

S/5

S/5
S/5

Datex-Ohmeda Hemodynamic modules

TM

NE12STPR Module, M-NE12STPR (rev. 01)

TM

NE12STR Module, M-NE12STR (rev. 01)

TM

NE12TPR Module, M-NE12TPR (rev. 01)

TM

S/5

NESTPR Module, M-NESTPR (rev. 01)

TM

S/5
S/5

S/5

NESTR Module, M-NESTR (rev. 01)

TM

NETPR Module, M-NETPR (rev. 01)

TM

ESTPR Module, M-ESTPR (rev. 04)

TM

S/5
S/5

ESTR Module, M-ESTR (rev. 04)

TM

ETPR Module, M-ETPR (rev. 04)

Technical Reference Manual Slot

Datex-Ohmeda Inc.
3030 Ohmeda Drive
53707-7550 MADISON, WIS
USA
Tel. [phone],Fax [phone]

www.us.datex-ohmeda.com

All specifications are subject to change without notice.

Document No. 800 1008-2

June 2001

Datex-Ohmeda Division,

Instrumentarium Corp.

P.O. Box 900, FIN-00031

DATEX-OHMEDA, FINLAND

Tel. [phone] Fax [phone]

www.datex-ohmeda.com

 Instrumentarium Corp. All rights reserved.

Table of contents

TABLE OF CONTENTS

HEMODYNAMIC MODULES

TABLE OF CONTENTS i

Table of figures iii

Introduction 1

1 Specifications 2

1.1 General specifications ..............................................................................................................................2

1.2 Typical performance .................................................................................................................................2

1.2.1 NIBP................................................................................................................................................2

1.2.2 ECG.................................................................................................................................................3

1.2.3 Pulse oximetry..................................................................................................................................3

1.2.4 Temperature.....................................................................................................................................4

1.2.5 Invasive blood pressure ....................................................................................................................4

1.2.6 Respiration ......................................................................................................................................4

1.3 Technical specifications............................................................................................................................5

1.3.1 NIBP................................................................................................................................................5

1.3.2 ECG.................................................................................................................................................5

1.3.3 Pulse oximetry..................................................................................................................................6

1.3.4 Temperature.....................................................................................................................................6

1.3.5 Invasive blood pressure ....................................................................................................................6

1.3.6 Respiration ......................................................................................................................................6

2 Functional Description 7

2.1 Measurement principle .............................................................................................................................7

2.1.1 NIBP................................................................................................................................................7

2.1.2 ECG.................................................................................................................................................7

2.1.3 Pulse oximetry..................................................................................................................................7

2.1.4 Temperature.....................................................................................................................................9

2.1.5 Invasive blood pressure ..................................................................................................................10

2.1.6 Respiration ....................................................................................................................................10

2.2 Main components...................................................................................................................................10

M-ESTPR/-ETPR/-ESTR modules...............................................................................................................10

M-NE12STPR/-NE12STR/-NE12TPR/-NESTPR/-NESTR/-NETPR modules .................................................11

2.2.3 NIBP board ....................................................................................................................................12

2.2.4 ECG board in 3-and 5-lead measurement........................................................................................14

2.2.5 ECG board in 12-lead measurement ...............................................................................................16

2.2.6 ECG filtering...................................................................................................................................18

2.2.7 STP board ......................................................................................................................................19

2.3 Connectors and signals...........................................................................................................................24

2.3.1 Module bus connector....................................................................................................................24

2.3.2 Front panel connectors...................................................................................................................25

2.3.3 Test points on boards .....................................................................................................................26

3 Service Procedures 28

3.1 General service information.....................................................................................................................28

3.2 Service check .........................................................................................................................................28

Document No. 800 1008-2

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Datex-Ohmeda S/5 monitors

3.2.1 Recommended tools......................................................................................................................28

3.2.2 Recommended parts......................................................................................................................29

3.3 Disassembly and reassembly..................................................................................................................39

3.3.1 M-ESTPR, M-ESTR, and M-ETPR modules........................................................................................39

3.3.2 M-NE12STPR/-NE12STR/-NE12TPR/-NESTPR/-NESTR/-NETPR modules.......................................39

3.4 Adjustments and calibrations..................................................................................................................40

3.4.1 Pressure safety level detection “OFFSET”.........................................................................................40

3.4.2 NIBP calibrations ...........................................................................................................................40

3.4.3 Temperature calibration .................................................................................................................42

3.4.4 Invasive pressure calibration ..........................................................................................................42

4 Troubleshooting 43

4.1 Troubleshooting charts ...........................................................................................................................43

4.1.1 NIBP..............................................................................................................................................43

4.1.2 NIBP error code explanation ...........................................................................................................46

4.1.3 ECG...............................................................................................................................................47

4.1.4 Pulse oximetry (SpO

4.1.5 Temperature ..................................................................................................................................48

4.1.6 Invasive blood pressure..................................................................................................................49

4.1.7 Impedance respiration ...................................................................................................................50

4.2 Troubleshooting flowcharts .....................................................................................................................51

4.2.1 M-NE12STPR and M-NESTPR module troubleshooting.....................................................................51

4.2.2 M-ESTPR, M-ESTR, and M-ETPR module troubleshooting .................................................................52

).....................................................................................................................47

2

5Service Menu 53

5.1 NIBP service menu .................................................................................................................................54

5.1.1 NIBP demo menu...........................................................................................................................55

5.1.2 NIBP calibration menu....................................................................................................................56

5.1.3 NIBP safety valve menu..................................................................................................................57

5.1.4 NIBP pulse valve menu...................................................................................................................58

5.1.5 NIBP buttons/leds menu................................................................................................................59

5.1.6 NIBP pneumatics menu..................................................................................................................60

5.1.7 NIBP watchdog menu.....................................................................................................................61

5.2 ECG service menu ..................................................................................................................................62

5.2.1 ECG setup menu ............................................................................................................................64

5.3 STP service menu ...................................................................................................................................65

5.3.1 STP calibration menu .....................................................................................................................67

6 Spare Parts 68

6.1 Spare parts list.......................................................................................................................................68

6.1.1 M-ESTP rev. 01, M-ETP rev. 00, M-EST rev. 00 .................................................................................68

6.1.2 M-ESTP rev. 02, M-ETP rev. 01, M-EST rev. 01 .................................................................................69

6.1.3 M-ESTP rev. 03, M-ETP rev. 02, M-EST rev. 02 .................................................................................69

6.1.4 M-ESTP rev. 04, M-ETP rev. 03, M-EST rev. 03 .................................................................................69

6.1.5 M-ESTP rev. 05, M-ETP rev. 04, M-EST rev. 04 .................................................................................69

6.1.6 M-ESTPR rev. 01, M-ETPR rev. 01, M-ESTR rev. 01...........................................................................70

6.1.7 M-ESTPR rev. 02, M-ETPR rev. 02, M-ESTR rev. 02...........................................................................70

6.1.8 M-ESTPR rev. 03, M-ETPR rev. 03, M-ESTR rev. 03...........................................................................70

6.1.9 M-ESTPR rev. 04, M-ETPR rev. 04, M-ESTR rev. 04...........................................................................70

6.1.10 M-NESTPR rev. 00, M-NETPR rev. 00, M-NESTR rev. 00 ...............................................................71

6.1.11 M-NESTPR rev. 01, M-NETPR rev. 01, M-NESTR rev. 01 ...............................................................72

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Document No. 800 1008-2

Table of contents

6.1.12 M-NE12STPR rev. 00, M-NE12STR rev. 00, M-NE12TPR rev. 00...................................................72

6.1.13 M-NE12STPR rev. 01..................................................................................................................72

6.1.14 Front panel stickers....................................................................................................................73

6.1.15 Front panel stickers for S/5 modules...........................................................................................74

7 Earlier Revisions 76

APPENDIX A 77

Service Check Form A-1

TABLE OF FIGURES

Figure 1 S/5 NE12STPR Module, M-NE12STPR ................................................................................1

Figure 2 Absorption of infrared light in the finger probe parts layout and schematic diagram................9

Figure 3 Front panel of M-ESTPR.....................................................................................................10

Figure 4 Front panel of M-NESTPR ..................................................................................................11

Figure 5 NIBP board functional block diagram.................................................................................12

Figure 6 3- and 5- lead ECG board block diagram ...........................................................................14

Figure 7 12-lead ECG measurement block diagram.........................................................................16

Figure 8 STP board block diagram...................................................................................................19

Figure 9 Temperature measurement principle .................................................................................20

Figure 10 Pressure measurement principle .......................................................................................20

Figure 11 Pulse oximetry measurement block diagram ......................................................................21

Figure 12 Serial communication and opto isolation of M-NESTPR/-NE12STPR ...................................22

Figure 13 Serial communication and opto isolation of M-ESTPR.........................................................23

Figure 14 Module bus connector (X1) pin layout ................................................................................24

Figure 15 M-NE12STPR and M-NESTPR module troubleshooting flowchart .........................................51

Figure 16 M-ESTPR Module Troubleshooting Flowchart ......................................................................52

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iv

Document No. 800 1008-2

INTRODUCTION

This Technical Reference Manual Slot provides information for the maintenance and service of the
hemodynamic modules. Please see also related Technical Reference Manual for information
related to system e.g. related documentation, conventions used, symbols on equipment, safety
precautions, system description, system installation, interfacing, functional check and planned
maintenance.

The S/5 M-ESTPR/-ESTR/-ETPR and S/5 M-NE12STPR/-NE12STR/-NE12TPR/-NESTPR/­NESTR/-NETPR are double width modules designed for use with S/5 monitors. The modules
provide general hemodynamic parameters. Later in this manual modules can be called w/o
system name S/5.

S/5 Hemodynamic modules

NOTE: Do not use identical modules in
the same monitor simultaneously.
The following modules are considered
identical:
M-ESTP/-EST/-ETP
M-ESTPR/-ESTR/-ETPR
M-NESTPR/-NESTR/-NETPR
M-NE12STPR/-NE12STR/-NE12TPR
M-MRI/-MRIP

NOTE: 12-lead ECG measurement
requires Display Controller, B-DISP.

Figure 1 S/5 NE12STPR Module, M-NE12STPR

Table 1 Options of S/5 hemodynamic modules

Parameter NE12STPR NESTPR NE(12)

STR

12

12-lead ECG • (•)(•)

N

NIBP ••••

E

ECG • • •••••

S

Pulse oximetry ••• ••

T

Two temperatures • • •••••

P

Two invasive blood pressures •• •• •

R

Impedance respiration • • •••••

NE(12)
TPR

ESTPR ESTR ETPR

Document No. 800 1008-2

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Datex-Ohmeda S/5 monitors

1 SPECIFICATIONS

1.1 General specifications

Module size 75 × 180 × 112 mm
W × D × H3.0 × 7.1 × 4.4 in
Operation temperature 10...40 °C / 50...104 °F

@ M-ESTPR/-ETPR/-ESTR

Module weight 0.6 kg / 1.3 lbs
Power consumption 6 W

@ M-NE12STPR/-NE12STR/-NE12TPR/-NESTPR/-NESTR/-NETPR

Module weight 1 kg
Power consumption about 9 W

1.2 Typical performance

1.2.1 NIBP

Oscillometric measurement principle.

Measurement range adult 25...260 mmHg

Pulse rate range accepted 30...250 bpm

Measurement interval from continuous to 1h, 2h, 4h

Typical measuring time adult 23 s

Initial inflation pressure adult 185 ±10 mmHg

Venous stasis adult 80 ±10 mmHg / 2 min.

Cuff widths please see User’s Guide

child 25...195 mmHg
infant 15...145 mmHg

infant 20 s

child 150 ±10 mmHg
infant 120 ±10 mmHg

child 60 ±10 mmHg / 2 min.
infant 40 ±10 mmHg / 1 min.

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Document No. 800 1008-2

1.2.2 ECG

S/5 Hemodynamic modules

Lead selection @ 12-lead ECG I, II, III, aVR, aVL, aVF, V1, V2, V3, V4, V5, V6
Lead selection @ other modules I, II, III, aVR, aVL, aVF, V
Sweep speeds 12.5, 25, 50 mm/sec

DISPLAY FILTER

Diagnostic @ 12-lead ECG 0.05...150 Hz
Diagnostic @ other modules 0.05...100 Hz

Monitoring 0.5...30 Hz (-3 dB, with 50 Hz reject filter)

0.5...40 Hz (-3 dB, with 60 Hz reject filter)

ST filter 0.05...30 Hz (-3 dB, with 50 Hz reject filter)

0.05...40 Hz (-3 dB, with 60 Hz reject filter)

HEART RATE FROM ECG

Range 30...250 bpm
Accuracy ±5 bpm or ±5 %, whichever is greater
Resolution 1 bpm
Update interval 5 s
Averaging time 10 s

ST LEVELS (in main software)

ST level range -9...+9 mm (-0.9...+0.9 mV)
Resolution 0.1 mm (0.01 mV)
Averaging calculated from 8 QRS

SYNCHRONIZATION

Direct ECG analog output of ECG, 1 V/1 mV
Pacer 5 V and 0.5...2.5 ms pulse, < 30 ms after pacer peak
Defibrillator 5 V and 10 ms pulse, < 35 ms after R-point synchronization

1.2.3 Pulse oximetry

Measurement range 40...100 %
Accuracy 100...80 %, ±2 digits

(% SpO

Display resolution 1 digit = 1 % of SpO
Display averaging time 20, 10 sec, beat-to-beat
Pulse beep pitch varies with SpO

The monitor is calibrated over the measurement range against functional saturation SpO

HEART RATE FROM PLETH

Measurement range 30...250 bpm
Accuracy 30...100, ±5 bpm,

Resolution 1 bpm
Display averaging 10 s

2 ±1 SD)

1

80...50 %, ±3 digits

50...40 %, unspecified

2

2 level

func.

2

100...250, ±5 %

1

1 SD (standard deviation) = 68 % of all readings in the specified range in stable conditions.

3

Document No. 800 1008-2

Datex-Ohmeda S/5 monitors

Adjustable pulse beep volume.

PLETH WAVEFORM

Scales 2, 5, 10, 20, 50 mod%, Auto

Start up scale is 20 mod% if AUTO is not selected to be the default setting.

1.2.4 Temperature

Measurement range 10...45 °C (50...113 °F)
(In rev. ESTP 03/ EST 02/ETP 02 or earlier: 15...45 °C (59...113 °F))

Measurement accuracy ±0.1 °C (25...45.0 °C)

Display resolution 0.1 °C (0.1 °F)
Temperature test automatic (every 10 min)
Probe type compatible with YSI 400 series

1.2.5 Invasive blood pressure

Measurement range -40...320 mmHg
Measurement accuracy ±2 mmHg or ±5 %
Zero adjustment range ±150 mmHg
Calibration range ±20 %
Scales upper limit is adjustable between 10 and 300 mmHg in steps of

±0.2 °C (10...24.9 °C)

10. Lower limit is 10 % of selected upper limit below zero.

Sweep speed 12.5, 25, 50 mm/s

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

1.2.6 Respiration

Measurement range 4...120 bpm
Accuracy ±5 bpm or ±5 %
Resolution 1 bpm
Averaging time 30 s
Update interval 10 s

RESPIRATION WAVEFORM

Sweep Speeds 6.25 mm/s and 0.625 mm/s

4

Document No. 800 1008-2

1.3 Technical specifications

1.3.1 NIBP

Deflation rate, PR dep. 5...13 mmHg/s
Inflation time 20...185 mmHg, 1...5 s

Automatic software control, max. inflation pressure

Over pressure limit, stops measurement after 2 seconds

Safety valve limits the maximum cuff pressure to 320 mmHg in adult/child mode or 165 mmHg in
infant mode. Independent timing circuit limits pressurizing (>5 mmHg) time to 2 minutes 10
seconds maximum in adult/child mode, and 1 minute 5 seconds in infant mode.

S/5 Hemodynamic modules

adult 280 ±10 mmHg
child 200 ±10 mmHg
infant 150 ±10 mmHg

adult 320 mmHg
child 220 mmHg
infant 165 mmHg

1.3.2 ECG

Zeroing to ambient pressure is done automatically.

Inflation pressure is adjusted according to the previous systolic pressure, typically 40 mmHg
above. If the systolic pressure is not found, inflation pressure is increased typically 50 mmHg.

Max. measurement time adult 2 min

child 2 min
infant 1 min

Pressure transducer accuracy is better than ±3 mmHg or ±2 % whichever is greater.
Max. error ±4 mmHg.

Protection against electrical
shock Type BF defibrillation proof

Defibrillation protection 5000 V, 360 J
Recovery time 2 s
Input impedance >2.5 MΩ (10 Hz)
CMRR >100 dB (ST)
System noise <40 µV (p-p, RTI)
Allowable offset ±300 mVDC
Gain range 0.2...5.0 cm/mV
Pacemaker pulse detection 2...500 mV, 0.5...2 ms pulses

Protection against electrical
shock Type CF defibrillator proof

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Document No. 800 1008-2

Datex-Ohmeda S/5 monitors

1.3.3 Pulse oximetry

Protection against electrical
shock Type BF defibrillation proof

1.3.4 Temperature

Measurement accuracy ±0.1 °C (25.0...45.0 °C)

Protection against electrical
shock Type CF defibrillation proof

NOTE: The accuracy of the measurement may be different from the specified, depending on
transducer/probe used. Please check the transducer/probe specification.

1.3.5 Invasive blood pressure

DIGITAL DISPLAY AVERAGING

Digital displays Art and P1 are averaged over 5 seconds and updated at 5 seconds intervals. All
other pressures have respiration artifact rejection.

±0.2 °C (10.0...24.9 °C)

Accuracy ±5 % or ±2 mmHg, whichever is greater
Transducer and input sensitivity

Filter 0...4 - 22 Hz adjustable
Zero set accuracy ±1 mmHg
Calibration resolution ±1 mmHg
Zero time less than 15 s
Protection against electrical
shock Type CF defibrillation proof

NOTE: The accuracy of the measurement may be different from the specified, depending on
transducer/probe used. Please check the transducer/probe specification.

1.3.6 Respiration

Excitation frequency @ 12-lead ECG 62.5 kHz

Excitation frequency @ other modules 31.25 kHz

Breath detection automatic, range 0.3...6 Ω manually adjustable minimum

Input dynamic range 0.2...6 Ω
Input impedance range 100...5000 Ω
Respiration Rate min. 4 bpm

Lead off detection >3 MΩ

5 µV/V/mmHg, 5 VDC, 20 mA max current

detection: 0.2, 0.4, 0.6, 0.8, 1.0

max. 120 bpm

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Document No. 800 1008-2

2 FUNCTIONAL DESCRIPTION

2.1 Measurement principle

2.1.1 NIBP

NIBP (Non-Invasive Blood Pressure) is an indirect method for measuring blood pressure.

The NIBP measurement is performed according to the oscillometric measuring principle. The cuff is
inflated with a pressure slightly higher than the presumed systolic pressure, and deflated at a
speed based on the patient’s pulse, collecting data from the oscillations caused by the pulsating
artery. Based on these oscillations, values for systolic, mean, and diastolic pressures are
calculated.

The following parts are necessary for the NIBP measurement:

• M-NE12STPR/-NE12STR/-NE12TPR/-NESTPR/-NESTR/-NETPR (or M-NIBP) module

S/5 Hemodynamic modules

• twin hose (adult or infant model)

• blood pressure cuffs (different sizes)

2.1.2 ECG

Electrocardiography analyzes the electrical activity of the heart by measuring the electrical
potential produced with electrodes placed on the surface of the body.

ECG reflects:

• electrical activity of the heart

• normal/abnormal function of the heart

• effects of anesthesia on heart function

• effects of surgery on heart function

See the User's Reference Manual for electrodes positions and other information.

2.1.3 Pulse oximetry

A pulse oximeter measures the light absorption of blood at two wavelengths, one in the near
infrared (about 900 nm) and the other in the red region (about 660 nm) of light spectrum. These
wavelengths are emitted by LEDs in the SpO
tissue and is finally detected by a PIN-diode opposite to LEDs in the probe. Pulse oximeter derives
the oxygen saturation (SpO
absorption at the two wavelengths and the arterial oxygen saturation SaO

probe, the light is transmitted through peripheral

2

) using empirically determined relationship between the relative

2

.

2

In order to measure the arterial saturation accurately, pulse oximeters use the component of light
absorption giving variations synchronous with heart beat as primary information on the arterial
saturation.

Document No. 800 1008-2

7

Datex-Ohmeda S/5 monitors

A general limitation of the above pulse oximetry principle is that due to only two wavelengths used
only two hemoglobin species can be discriminated by the measurement.

The modern pulse oximeters are empirically calibrated either against fractional saturation

frac;

SaO

2

2

fracSaO

2

=

HbO

2

++

binDyshemogloHbHbO

Formula 1

or against functional saturation SaO

HbO

=

2

funcSaO

which is more insensitive to changes of carboxyhemoglobin and methemoglobin concentrations in
blood.

The oxygen saturation percentage SpO
the functional saturation SaO
measurement relative to SaO2func can be maintained even at rather high concentrations of
carboxyhemoglobin in blood. Independent of the calibration method, pulse oximeter is not able to
correctly measure oxygen content of the arterial blood at elevated carboxyhemoglobin or
methemoglobin levels.

Plethysmographic pulse wave

The plethysmographic waveform is derived from the IR signal and reflects the blood pulsation at
the measuring site. Thus the amplitude of the waveform represents the perfusion.

Pulse rate

The pulse rate calculation is done by peak detection of the plethysmographic pulse wave. The
signals are filtered to reduce noise and checked to separate artifacts.

func;

2

2

HbHbO

2

+

measured by Datex-Ohmeda module is calibrated against

2

func. The advantage of this method is that the accuracy of SpO

2

Formula 2

2

Probe

8

Document No. 800 1008-2

The standard probe is a finger clamp probe which contains the light source LEDs in one half and
the photodiode detector in the other half. Different kinds of probes are available from Datex­Ohmeda.

Intensity of
transmitted
light

I

max (DC-component)

S/5 Hemodynamic modules

I

max

AC-component

I

min

Transmitted
light

Incident light

Emitter

RED

Detector

No pulsation

IRED

Pulsatile blood

SpO sensor cable

2

Variable absorption
due to pulse added
volume of arterial
blood

Arterial blood

Venous blood

Tissue

Time

SpO sensor connector

2

6

GND

7

I

LED

4

5

GND

8

V

B

R

C

1

I

S

9

GND

Figure 2 Absorption of infrared light in the finger probe parts layout and schematic

2.1.4 Temperature

The temperature is measured by a probe whose resistance varies when the temperature changes,
called NTC (Negative Temperature Coefficient) resistor.

The resistance can be measured by two complementary methods:

• Applying a constant voltage across the resistor and measuring the current that flows through

diagram

it

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Document No. 800 1008-2

Datex-Ohmeda S/5 monitors

• Applying a constant current through the resistor and measuring the voltage that is generated

across it.

In Datex-Ohmeda modules the two methods are combined in a form of a voltage divider. The NTC­resistor 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.

2.1.5 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.

2.1.6 Respiration

Impedance respiration is measured across the thorax between ECG electrodes. The signal of the
respiration is made by supplying current between electrodes and by measuring the differential
current from the electrodes. The signal measured is the impedance change caused by breathing.
From these impedance changes, respiration rate is calculated, and respiration waveform is
displayed on the screen.

2.2 Main components

2.2.1 M-ESTPR/-ETPR/-ESTR modules

T1

T2

ECG+
Resp

SpO

P1

P2

2

ECG

Lead

Start

Wedge

Zero

P1

Zero

P2

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Document No. 800 1008-2

Figure 3 Front panel of M-ESTPR

The M-ESTPR, M-ETPR, and M-ESTR modules contain two main PC boards, the STP board and the
ECG board. They work independently. Both of them have their own processor and software EPROM.
Some components on the boards are not used in ETPR and ESTR modules.

In M-ESTPR module, additionally, there are two small boards, the SP input and the ECG input

S/5 Hemodynamic modules

boards, attached to the front panel of the module. The front panel has six connectors and four keys.
The connectors are two for temperature measurement, two for invasive blood pressure
measurement, one for ECG, and one for SpO

measurement. The keys are for ECG lead, Start

2

Wedge, P1 zero, and P2 zero.

In M-ETPR module, there are two small boards, the ECG input board and the 2P input board
attached to the front panel of the module. The front panel has five connectors and four keys. The
connectors are two for temperature measurement, two for invasive blood pressure measurement,
and one for ECG

measurement. The keys are for ECG lead, Start Wedge, P1 zero, and P2 zero.

In M-ESTR module, there are two small boards: the S input board and the ECG input board,
attached to the front panel of the module. The front panel has four connectors and one key. The
connectors are two for temperature measurement, one for ECG, and one for SpO
The key is for ECG lead select.

NOTE: M-ESTP rev. 03, M-ETP rev. 02 and M-EST rev. 02 and all earlier revisions have separate T
and SP input boards.

2.2.2 M-NE12STPR/-NE12STR/-NE12TPR/-NESTPR/-NESTR/-NETPR modules

measurement.

2

Auto

On/Off

NIBP

T1

ECG+
Resp

P1

Start

Cancel

P2

T2

Zero

SpO

2

P1

Zero

P2

Figure 4 Front panel of M-NESTPR

The M-NESTPR, M-NETPR, and M-NESTR modules contain three main PC boards, the STP board,
the ECG board, and the NIBP board. They work independently. Each of these has their own
processor and software EPROM.

The M-NE12STPR, M-NE12TPR, and M-NE12STR contain three main PC boards, The STP board,
the ECG board and the NIBP board. They work independently. Each of them has their own
processor. The STP board and NIBP board have software EPROM. In the ECG board the software is
in flash memory. The STP and NIBP boards are the same as in M-NESTPR module but the ECG
board and ECG input board are different.

In M-NESTPR module, there are two small boards, the SP input and the ECG input board attached
to the front panel of the module. The front panel has seven connectors and four keys. The
connectors are two for temperature measurement, two for invasive blood pressure measurement,
one for ECG, one for NIBP, and one for SpO

measurement. The keys are for NIBP Auto On/Off,

2

NIBP Start/Cancel, P1 zero, and P2 zero. The structure of M-NE12STPR is similar except the ECG
board and ECG input board are different.

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Datex-Ohmeda S/5 monitors

In M-NETPR module, there are two small boards, the 2P input board and the ECG input board,
attached to the front panel of the module. The front panel has six connectors and four keys. The
connectors are two for temperature measurement, two for invasive blood pressure measurement,
one for ECG, and one for NIBP. The keys are for Auto On/Off, Start/Cancel, P1 zero, and P2 zero.
The structure of M-NE12TPR is similar except the ECG board and ECG input board are different.

In M-NESTR module, there are two small boards, the ECG input board and the S input board,
attached to the front panel of the module. The front panel has five connectors and two keys. The
connectors are two for temperature measurement, and one for SpO
and one for NIBP. The keys are for Auto On/Off, Start/Cancel. The structure of M-NE12STR is
similar except the ECG board and ECG input board are different.

2.2.3 NIBP board

CUFF

ZERO
VALVE

EXHAUST
VALVE 2

JOIN ING
CHAMBER

EXHAUST VALVE 1

BLEED VALVE

CHECK VALVE

measurement, one for ECG,

2

PUMP and

PUMP

M

VALVE
DRIVER

B1 B2

t
o

/
f
r
o

m
m

o
d
u
l

e
b

u
s

X1

PRESSURE

S

TRAN

-

D

UCERS

AD-CON­VERTER

POWER-UP

RESET

RS485
INTER F.

EEPRO
(C alib­ration
Data)

Figure 5 NIBP board functional block diagram

Pressure transducers

OVERPRESSURE CONTROL

M

Write protect switch

CPU
80C51FA

NTERNAL

I
WATCHDOG

ADDRESS BUS

ADDRESS
DECODER

ADDRESS
LATCH

WATCHDO G

TIMER

RAM

DATABUS

+

1

5

EPROM

D

V

FRONT
PANEL

KEYS

SOFT ­WAR E

CON TRO L

12

Document No. 800 1008-2

The NIBP board contains two pressure transducers. They are of piezoresistive type. One is used for
measuring the pressure of the blood pressure cuff and the pressure fluctuations caused by arterial
wall movement (B1). The other is used for detection of cuff hose type, cuff loose and cuff occlusion
situations etc. (B2). The transducers are internally temperature compensated. They are supplied by
a constant voltage and their output voltage changes up to 40 mV max. (50 kPa, 375 mmHg).

Signal processing

Two signals from the pressure transducers are amplified and sent to A/D converter. After the
converter, digitized signals are sent to microprocessor for data processing. Before the converter,
one of the signals is used to adjust the offset to the pressure safety level.

The NIBP board is controlled with 80C51FA microprocessor at 16 MHz oscillator frequency.

Memory

NIBP program memory (EPROM) size is 128k × 8. RAM size is 32k × 8 bit and it stores variable
values in NIBP measurement. EEPROM is size 64 × 16 bit and is used to store the calibration
values for the pressure transducers, the pulse valve constants gained during measurements, the
PC board identification, and module serial number.

Software control

Software controls valves and pump. In addition to the individual on/off signals for each component
there is a common power switch for the valves and the pump that can be used at pump/valve
failures.

S/5 Hemodynamic modules

In addition to external RS485 reset line the microprocessor system is equipped with its own power­up reset. See the section in ECG board’s description: “RS485 communication”

Watchdog timer

The NIBP board is equipped with software independent safety circuit to disconnect supply voltages
from the pump and the valves if the cuff has been pressurized longer than preset time. As soon as
the cuff pressure rises over a specifiedpressure limit, timer starts counting. The timer is adjusted to
stop the pump and open the valves in 2 minutes 10 seconds in adult/child mode and in 1 minute
5 seconds in infant mode.

Valves

Exhaust valves are used for emptying the cuff and the joining chamber after the measurement.
Exhaust valve 1 is also used as safety valve in infant mode. Valve opens at 165 mmHg. Exhaust
valve 2 is also used as safety valve in adult mode and opens at 320 mmHg.
Bleed valve is used for emptying the cuff during measurement. Zero valve is used for connecting
the pressure transducer B1 to open air.

Power supply section

All connections are established via 25-pin connector (D-type, female). The module needs +5 V,
±15 V, and +15 VD (dirty) power supply to operate. The pump and the valves use separate +15 VD
power line. The supply voltages are generated in the power supply section of the S/5 monitor. The
reference voltages ±5 V

and +10 V

ref

are generated on the NIBP board.

ref

13

Document No. 800 1008-2

Datex-Ohmeda S/5 monitors

2.2.4 ECG board in 3-and 5-lead measurement

Patient signals are connected to overload protection circuits (resistors and gas-filled surge
arresters) and analog switches to instrumentation amplifiers. Then the signals are amplified by 480
and limited by slew rate. Then they are A/D-converted, analyzed and transferred to module bus in
digital form.

PATIENT

OVERLOAD PROTECTION

DEFIBRILLA­TION
DETECTOR

uP

SLEW­RATE
DETECTOR

HP
Filter

uP

ANTI­ALIAS

RL

ANALOG SWITCHES

SLEW­RATE
DETECTOR

uP

ANTI­ALIAS

SUPPLY
VOLTAGES

FCN

SLEW­RATE
DETECTOR

uPuPuP

uP

HP
Filter

ANTI­ALIAS

A/D

MICRO­PROCESSOR
(uP)

HP
Filter

SLEW­RATE
DETECTOR

uP

uP

HP
Filter

ANTI­ALIAS

LEAD SELECTION LOGIC
Controlled by ECG lead
selection signals from uP

Resp
amplifier

31 kHz
from uP

Sync. Rectifier

Amplifier

Figure 6 3- and 5- lead ECG board block diagram

Analog ECG section

ECG cable is connected to connector pins E1 to E6 on the input board which contains an overload
protection circuit. Leads are connected to amplifiers via analog switches. States of the switches
depend on the cable type. Lead-off, noise and pacemaker are detected by a slew rate detector.

14

Document No. 800 1008-2

ISOLATION

POWER
SOURCE

POWER
SOURCE

OPTO­COUPLER

OPTO­COUPLER

to STP Board

DIRECT
ECG

DIRECT
ECG

S/5 Hemodynamic modules

Lower frequency is determined by high pass (HP) filter 0.5 Hz (monitor bandwidth) or 0.05 Hz
(diagnostic or ST- bandwidth).

Respiration section

3-lead cable The analog switches control the current supply source of the impedance respiration measurement,

and the lead selection for the 3-lead cable can be seen from the following table:

Table 2 Lead selection and coding for the 3-lead cable

Selected lead Current source between Signal measured from

IR - L N

II R - N L

III L - N R

Position on

IEC standard coding AAMI standard coding

body surface

right arm R = red RA = white

left arm L = yellow LA = black

left leg F = green LL = red

5-lead cable When the 5-lead cable is used, the current source is between L-F and the signal is measured from

the N, independently on the lead selection.

The respiration amplifier consist of the operational amplifiers, and the components around them.
There is an analog switch for controlling the gain of the first stage of the preamplifier. Synchronous
rectifier consists of the analog switches, which are used for detecting the respiration signal from 31
kHz amplitude modulated raw signal. The amplifier stage consists of the differential amplifier and
the last amplifier. The differential amplifier consists of the operational amplifiers and the
components around them. This stage is AC-coupled on both sides for minimising the offset
voltages. The last amplifier is used for amplifying the signal derived from differential amplifier
stage. The respiration signal is zeroed at the beginning of the measurement. Zeroing is also used
for fast recovering the measurement after the motion artefact. This is done in amplifier section.

NOTE: The respiration measurement is switched OFF for 20 seconds when defibrillation is detected
at the defibrillation detector.

Microprocessor section

Microprocessor contains RAM and EPROM memories. The processor uses external EEPROM
memory. The microprocessor’s internal 8-channel A/D-converter converts the ECG-signals to
digital form. See the section in ECG board’s description: “RS485 communication

Serial communication

Communication with the module bus is made through RXD and TXD pins. See the section in STP
board’s description: “Serial communication”.

15

Document No. 800 1008-2

Datex-Ohmeda S/5 monitors

Isolated section

The patient isolation of ECG is 5 kV.

NOTE: The isolation has been changed from the earlier revisions.

WARNING Do not touch battery operated monitor during defibrillation procedure.

See the “Isolated section” in STP board description.

Power supply section

See the “Power supply section” in STP board description.
There is a test connector (X20) on the board for voltages +5 VREF, +5 V, +12 V, GND and -12 V.

2.2.5 ECG board in 12-lead measurement

The 12-lead ECG measurement consists of the functions, which are shown in the figure 7. All
functions are located in the ECG board except the front panel connector and the ECG input board.

Front panel connector and
ECG input board

Input protection and filtering

Respiration
impedance
amplifiers

RS 485
communication

Respiration
impedance
supply

ECG CPU

Power
supply

ECG preamplifiers

ECG amplifiers

and

Baseline

restoration

NV memory

Pacer

detection

16

Document No. 800 1008-2

Isolation

to STP board

Isolation

Figure 7 12-lead ECG measurement block diagram

Front panel connector and ECG input board

The connector for the 12-lead ECG cable is a green 12 pin Nicolay type connector. 3- or 5-lead
cables with blue connector cannot be connected to this connector. The ECG input board contains
high voltage resistors and a connector for ECG board.

Input protection and filtering

The input protection is implemented with protection diodes, which are connected to analog power
supply voltage and ground. The input filtering for ECG measurement is done with discrete
components. The measured signal is AC-coupled for respiration measurement. The signal from the
respiration supply is AC coupled. There are also the overload protection diodes for respiration
measurement supply.

ECG preamplifiers

The buffer amplifiers are used for each lead except N/RL. The leads off detection is implemented
by measuring the level of the input buffer amplifiers with A/D converter of CPU. The ECG signals are
measured using differential amplifiers.

S/5 Hemodynamic modules

ECG amplifiers and baseline restoration

The function of the ECG amplifiers and baseline restoration is to amplify the signal and to restore
the baseline of the signal in the middle of the display after the change of the signal level e.g. after
the change of the DC offset voltage.

Pacer detection

Pacer detection has been made by using two slew rate detector circuits. The pacer detection
amplifiers have been realized at the front of the slew rate detectors independently from the ECG
measuring channels.

Respiration impedance supply

The 62.5 kHz sine wave generator is used as the respiration measurement signal supply. Analog
switches are used for connecting the sine wave to the ECG leads to be measured.

Respiration impedance amplifiers

Buffer amplifiers are used in respiration measurement. Analog switches are used for selecting the
measurement leads. There are also additional amplifiers for increasing the respiration signal gain.
Respiration is always measured between R and F, independently on the ECG lead selection.

ECG CPU

The CPU is a 16 bit H8/3048 single-chip microcomputer. It contains 128 kbytes of flash memory
and 4 kbytes of RAM. The clock frequency is 16 MHz.

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Document No. 800 1008-2

Datex-Ohmeda S/5 monitors

RS485 communication

The communication to the CPU board of the monitor uses RS485 protocol. The RS485 driver
circuits are optically isolated from the processor of the module. PWM signal is used for direct ECG
signal. Direct ECG signal is available from the X2 connector of the UPI board or from the PT module.

Power supply

The ECG board has a driver controlled half bridge switching power supply with 5 kV isolation. The
supply voltages have been regulated with linear regulators.

2.2.6 ECG filtering

The S/5 monitors have three ECG filtering modes:

MONITORING 0.5...30 Hz (with 50 Hz reject filter)

DIAGNOSTIC @ 12-lead ECG 0.05...150 Hz
DIAGNOSTIC @ other modules 0.05...100 Hz

0.5...40 Hz (with 60 Hz reject filter)

ST FILTER 0.05...30 Hz (with 50 Hz reject filter)

0.05...40 Hz (with 60 Hz reject filter)

The purpose of filtering is to reduce high frequency noise and low frequency (e.g. respiratory)
movement artifacts.

Monitor filter is used in normal monitoring. Diagnostic filter is used if more accurate diagnostic
information is needed. ST filter gives more accurate information of ST segment, but reduces high
frequency noise.

The high-pass filters 0.5 Hz and 0.05 Hz are done with hardware. The monitor sends a command to
the hemodynamic module determining which of the corner frequencies 0.5 Hz or 0.05 Hz is to be
used.

The 50 Hz and 60 Hz reject filters are both low-pass filters with zero at 50 Hz or 60 Hz
correspondingly and they are done with software. They are for the mains supply filtering. When
these filters are used, 3 dB value for low-pass filter is 30 Hz or 40 Hz.

In diagnostic mode the upper frequency is limited by hardware and the -3 dB frequency is 100 Hz
for 3 or 5 lead ECG measurement. For 12 lead ECG the upper frequency is 150 Hz and it is limited
by software.

18

Document No. 800 1008-2

2.2.7 STP board

S/5 Hemodynamic modules

Patient connectors

Front panel
keys

Power
isolation
section

Isolation
transformer

TEMP
measuring
unit

Temp AD

AD-converter

- 8 chn

- 12 bit

INV
PRESS
measuring
unit

Press AD

Pox AD

Serial device communication

µprocessor unit

RAM internal 2K

external 16K

EPROM 48K

RS communication

Patient isolation

POX pre­amplifier

POX

gain

control

Re d

Module
bus
data

Reset

Opto
isolation

ver

i
dr

Ds
LE

ox

g

rin

su

ed

measuring

ea

IR

m

Intensities

Non volatile
memory

P

Figure 8 STP board block diagram

Microprocessor unit

As processor, Intel’s 80C196KC-16 is used. There are external memories, an 8-bit data bus, a 16
MHz oscillator, an open collector reset, and a watchdog timer. Three A/D-converters within the
processor are used. The processor’s internal UART communicates with the CPU board.

High speed I/O is used to obtain pulse control sequence necessary for pulse oximetry
measurement. It gets its timing clock from the oscillator.

Power
non­isolation
section

Power for
module

Power
reset

Power for
Communication

Module bus connector or

connector to NIBP Board (NESTPR)

RS485 Driver
for module
reset

Module reset

RS485 Driver
for data

Module data

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Document No. 800 1008-2

Datex-Ohmeda S/5 monitors

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.

0 °C => 7K357
15 °C => 3K541
25 °C => 2K253
38 °C => 1K301
45 °C => 984R1

+5Vreference

NTC

Figure 9 Temperature measurement principle

Invasive blood pressure measurement unit

Isolated +5 V voltage is supplied to the pressure transducer. From the bridge connection a
differential voltage, which depends on pressure and supplied voltage, is calculated (see the
formula below).

= Uin × pressure × 5 V, where Uin is 5 V

U

out

= 25 V × pressure [mmHg]

Þ U

out

Pressure amplification is realized in the instrumentation amplifier. Gain of the amplifier is set so
that the level of the signal transferred to A/D converter stays within the measurement range even
when there are circumstantial offsets or offsets caused by the transducer. There is a filter before the
amplifier to attenuate high frequency disturbances.

A1

to AD
converter

offset

20

Document No. 800 1008-2

Vin

Pressure
transducer

Vout

Input
Filter

Figure 10 Pressure measurement principle

Instrumentation
amplifier

G

to AD converter

Pulse oximetry measurement section

S/5 Hemodynamic modules

I=5-350mA

Probe

Preamplifier
Current - to - Voltage
converter

LED driving circuit

Level of LED current
measurement and
feedback circuit

G =1/4096-1

Digitally controlled
attenuator

Amplifier

IRed LED intensity
adjustment

Red LED intensity
adjustment

Level of LED current indication (to CPU)

IR DC level

G = 275

Two step
AC amplifier

G =16
or 63

G =16
or 63

IRed AC signal

for NESTPR
G =18
or 125

Red AC signal

Red DC level

Figure 11 Pulse oximetry measurement block diagram

LED control signals

The processor sends pulse width modulated signals, IRED intensity and RED intensity, which are
converted to DC voltage and filtered. By switches either RED or IRED intensity is sent forward to
amplifier in LED driving circuit.

LED driving circuit

Voltage difference which corresponds to LED current, is measured by the differential amplifier
circuit and its output is sent back to the processor in 0 to 5 V level. There are feedback circuits from
LED current measurement and LED intensity control.

Background light is measured by picking up a sample from the signal. The sample is modified to 0
to 5 V level and sent to the processor.

Measured signal preamplification

Preamplifier is current-to-voltage converter with gain selection. The higher gain is used for
measuring of thin tissue.

Digitally controlled amplifier

D/A converter is a digitally controlled amplifier after which there is another constant amplifier.

Document No. 800 1008-2

21