Novametrix Medical Systems OXYPLETH 520A User manual

OXYPLETH
(Service Manual
Pulse Oximeter
Model 520A
August 31, 1992
Catalog Number 5693-90-00
Novametrix Medical Systems Inc. Wallingford, Connecticut, U.S.A. 06492.
Copyright ©1992. All rights reserved. No part of this manual may be reproduced
without the written permission of Novametrix Medical Systems Inc.

Revision History
August 31, 1992 Release 00. This manual replaces all preliminary versions.
Based on Revision 2.0 CPU software.

Section Revision History
[This page intentionally blank.]

G Guarantee
Equipment manufactured or distributed by Novametrix Medical Systems Inc., is
fully guaranteed, covering materials and workmanship, for a period of one year
from the date of shipment, except for certain disposable products and products with
stated guarantees other than one year. Novametrix reserves the right to perform
guarantee service(s) at its factory, at an authorized repair station, or at the
customer’s installation.
Novametrix’ obligations under this guarantee are limited to repairs, or at
Novametrix’ option, replacement of any defective parts of our equipment, except
fuses, batteries, and calibration gasses, without charge, if said defects occur during
normal service.
Claims for damages during shipment must be filed promptly with the transportation
company. All correspondence concerning the equipment must specify both the
model name and number, and the serial number as it appears on the equipment.
Improper use, mishandling, tampering with, or operation of the equipment without
following specific operating instructions will void this guarantee and release
Novametrix from any further guarantee obligations.
Service Department
For factory repair service, call toll free
1-800-243-3444
In Connecticut, call Collect [phone]
Telex 956-054
Facsimile [phone]
Caution: Federal (U.S.A.) law restricts this device to sale, distribution, or use by or
on the order of a licensed medical practitioner.
Copyright ©1992, Novametrix Medical Systems Inc. This document contains
information which is proprietary and the property of Novametrix Medical Systems
Inc., and may not be reproduced, stored in a retrieval system, translated,
transcribed, or transmitted, in any form, or by any means, without prior explicit
written permission from Novametrix Medical Systems Inc.

Contents
Section Page
Revision HIStory............ rien Res. ii
¡CORR G.............. iv
Contents .be Cioe ν
List of FÍgUFeS ....ooconccoaoncnnoncnncconananananccncononannnanoancrncnnarononanas Fieno, ix
List Of TablesS ...ommacononioonnccnnnaraonncinnananacnoncarancnnanaanancrnranaoonero Te... x
Introduction ИИ T eee 1
Purpose eee 00 000000 eee nee e eee n onen Penn Mi... 1
Technology Description Nb ϱϱ”ϱ”ϱ”ϱ”-- 12... 1
Conventions Used In This Manual ee 1.3 せ … せ ……… 2
Acknowledgments ss 1.4... 2
Patlent Safety ...coomooccconccoonanannnnocanaccncnanana ono nornanaananonranaoas nens μμ 3
Warnings ..........ccrrrirrerierrerini nine cirie enen iene re neo neo nieene nen eezioneo 人 4
CautionS .ee 4................ 5
Front Panel .................svverrrrrrrrrerezezineeneeneseneeni sere nenerenazananzone 5. 6
Rear & Top Panels ss srsesse 6 ................. 7
Summary of Operatlon .000.0100 이 아 나 아 아 아 아 아 어 아 아 에 이 이 이 미 이 이 이 이 다 아아아 PT 8
Мепи Тгее .......... „иене нии ο ϱουυυυσσυυ, μμ 9
Electronic Theory Of Operation ss Drena 13
2472PowerSuppiyBoard............................................ 9.1............. 13
AC Mains and Battery Operation Overview .......... 9.1.1.......... 13
AC Mains Operation i 9.1.2.......... 14
Battery Operation ............... ーー ドー 9.1.3... 14
2471MainBoard.............................. erene 9.2............. 15
Power On/Off Control Circuitry pb iii 9.2.1 .......... 15
Power SUpplies ...................... rienza 9.2.2.......... 16
VoltageReferences .............................................. 9.2.3.......... 17
Preserving RAM and Real Time Clock Data ......... 9.2.4 .......... 17

Contents
Low Battery VoltageShutdown............................ 9.2.5 .......... 17
TimingSeguencer .......................................... 9.2.6 .......... 18
DataSamplingController..................................... 9.2.7 .......... 18
Sensor LED Drive Circuits „eee 9.2.8 .......... 19
Sensor PhotodiodeReturnPath .......................... 9.29.......... 20
Calibrating the 20-Bit Analog-to-Digital Convertors 9.2.10....... 21
20-Bit Analog-to-Digital Conversion ...................... 9.2.11........ 22
Sensor Status Decoding and Conversion ............. 9.2.12........ 22
Sensor Status Parameters „ee 9.2.13... 23
Microprocessor .......................... e ελν λεν 9.2.14........ 24
Memory Nt 9.2.15 24
Real Time Clock (RTC)... iii 9.2.16........ 25
Sound generator a 9.2.17 ........ 25
Keypanelinterface............................................. 9.2.18 ........ 26
Display Interface ené 9.2.19 ........ 26
/ODeviceController.......................................... 9.2.20........ 27
Watchdog Timer .................................... 9.2.21 ........ 27
Serial 1/0 Controller i 9.2.22 ........ 28
RS232 Seral Communication 上 … せ … せ … せ …『………………………………・ 9.2.23 ........ 29
Maintenance eomocccccccnconcnonononannnccnnonanononannonnanccccanancnnananaanonoss 10 ............ 31
General et 10.1........... 31
Maintenance ScheduleS iii 10.2 ........... 31
CleaningandsSterilization......................................... 10.3........... 32
Model520A4Monitor............................................. 10.3.1 ........ 32
FingerSensor ............................................ 10.3.2 ........ 32
Y-SENSOR™ and Y-STRIP™ Taping System .....10.3.3 ........ 32
BatteylifeandMaintenance...................................... 10.4........... 32
AC Mains rennes 10.5 ........... 33
Replacing the AC MainsFusef($) .......................... 10.5.1 ........ 33
Changing the AC Mains Voltage ........................... 10.5.2........ 33
Assembly ExChanges ........... ii 10.6 ........... 34
ChangingSystem Software ........................................... 10.7........... 37
Troubleshooting serie eeeserrseerescensescreraes 11... 39
Functional Test esse 12............ 43
Introduction i 12.1 ........... 43
MonitorFunctionalTest............................................... 122........... 43
SpecialPowerUpfFunctions.......................................... 12.3........... 45
Ассигасу ΤΘΦΙ een sareseressanaza 13............ 47
Introduction ss. LEA 47

Section Contents
Calibration TestS ........cccnnccnnonasanancccnnnanananonnccrarnnnananconronanasas 14............ 51
Introduction ie 14.1 ........... 51
Equipment Required and Test Setup ............................. 14.2 ........... 51
Power Supplies ss 14.3 ........... 52
EPROM Checksum and Automatic Tests ...................... 14.4 ........... 53
Keyboardlesit....................................................... 145........... 54
Матз Овес! Тез! ............. eee 14.6 ........... 54
Low BatteryCheck............................... нии 14.7... 54
Functionality and ACCUrACy i 148........... 55
Safety ChEckSs ..... io 14.9... A 58
Completion Of Tests ............ esa 14.10......... 58
Test Fixtures erene 14.11......... 59
ProductionTestSoftware ............................................ 1412......... 59
MonitorTesti-Automaticlest........................... 14.12.1 ...... 60
Monitor Test 2 - RAM Test eee 14.19.9...... 60
Monitor Test 3 - ROM Checksum test ................... 14.123...... 60
Monitor Test 4 - Real Time Clock test ................... 14.124. ...... 60
Monitor Test 5 - Audio Volume Test ..................... 14.12.5 ...... 60
Monitor Test 6 - Audio Frequency Test ................. 14.12.6 ...... 60
Monitor Test 7 - Rs232 loopback Test .................. 14.12.7 ...... 61
Monitor Test 8 - Key board Test 4. 14.12.8 ...... 61
Monitor Test 9 - Mains detect test ......................... 14.12.9...... 61
Monitor Test 10 - 20 bit ADCs Test ....................... 14.12.10.... 61
Monitor Test 11 - 8 bit adc test. ............................. 14.12.11 .... 61
Monitor Test 12 - Display ADC channels .............. 14.12.12 ....62
Monitor Test 13 - 520A -> PC Interface ................ 14.12.13.... 62
Connecting to other Equipment ss... 15............ 63
Connecting the ThinkJet Printer .................................... 15.1 ........... 63
Connecting the Model 315 Printer ................................. 15.2 ........... 64
Connecting Seiko DPU-411 Thermal Printer ................. 153. 64
Analog Output Module eee een nn 15.4 ........... 65
Analog Output Setup ss 15.5........... 67
Spécifications ss 16............ 69
General eee ee nee eo ne ee anne 16.1 ........... 69
Oxygen Saturation (SpO»2) Section .............................. 16.2 ........... 69
Pulse Rate (PR) Section … せ … せ ……………… ト ーー 16.3 ........... 69
General Specifications せ ……………… せ ムー トー ドド トー バー 16.4 ........... 70
AdditionalFeatures...................................... 6 16.5 ........... 70
AccessorleS ee 이 00900000 17... 72
Model 520A sense 17.1... 72

Contents
Parts LiStS nr ssrsssssnssenesnrenee 18............ 75
5693-01 02 MANNASSY..................................... 18.0.2 .…… 75
2471-01 Ol MAINBOARDASSY........................ 18.0.3........ 76
2472-01 00 POWER SUPPLY BOARD ASSY.....18.0.4........ 79
5673-01 00 REAR PANEL ASSY ........................ 18.0.5........ 80
5719-01 00 FRONTPANELASSY..................... 18.0.6 ........ 80
2473-01 01 ALERT BOARD ASSY...................... 18.0.7 ........ 81
5720-01 00 DISPLAY ASSY, MODEL 520A ....... 18.0.8........ 81
5713-01 00 SPEAKER ASSY, OXYPLETH ........ 18.0.9 ........ 81
5714-01 00 BATTERY HARNESS ASSY............. 18.0.10...... 81
5728-01 02 CABLE ASSY, SAO2 INPUT ........... 18.0.11...... 81
5765-01 00 ТОР СО\УЕА АЗЗУ\........... ини, 18.0.12...... 82
5766-01 01 BOTTOM COVER ASSEMBLY ........ 18.0.13 ...... 82
Schematic and Assembly Drawings ......................0...00.... 19............ 83

List of Figures
Description Page
Figure 1 ................ FrontPanelDescription................................... 000. 6
Figure2................. Rear and Top PanelDescriptions .................................... 7
Figure 3 ................. Data Sampling Timing..…....................... erne 19
Figure4................. Power Entry Fuse Access DoorOpening....................... 33
Figure5................. Fuse Removal................. ses anon 33
Figure 6 ................. Power Entry Module Voltage Selector Drum Removal ... 34
Figure7................. Power Entry Module Voltage Selection Adjustment ........ 34
Figure 8 ................. Removing the Top Cover... eine 35
Figure9................. Monitor Assembly eee enn nes 35
Figure 10 ................ 520A Assembly with 2471 Main Board Removed ........... 36
Figure 11 ................ Changing the System Software EPROM......................... 37
Figure 12................. Softkey identification.................................... ee 46
Figure 13................. Installation of Jumper Wire on 2471 Main Board ............ 53
Figure 14................. Test Fixture Schematics nenene 59
Figure 15................ ConnectingtheThinkdetPrinter..................................... 63
Figure 16................ Connecting the Model 315 Printer n 64
Figure 17................ Configuration of Seiko Thermal Printer. ................. 65
Figure 18................ Connecting the Seiko Model DPU-411 Printer. ............... 65
Figure 19................ Analog Output Module be 66
Figure 20 ................ Analog OutputModulePinouts ..................................... 66
Figure2i................ Analog Output Setup eee 67

T List of Tables
Description Page
Table 1 eee Display Command/Datatable.......................................... 26
Table2................. CSI/O Decode Lines remate 28
Table3................. SpO2 Display tolerances for TB500B settings ................ 49
Table 4 ................ System EPROM Checksums ........................................ 53
Table SL ................. SpO» Display tolerances for TB500B settings ................ 57
Table 6 ................. Monitor Test 12, ADC Limits si 62
Table 7 ................. Analog Output Module Voltage Tolerances .................... 68
Table 8 ................. Schematic and AssembiyDrawings................................ 83

Section List of Tables
[This page intentionally blank]

Introduction
Purpose 1.1
This manual has been prepared for technicians servicing the Novametrix Model
520A Pulse Oximeter monitor. It presents technical information relating to the
monitor’s theory of operation, maintenance, calibration and repair. Refer to the
Pulse Oximeter Model 520A User's Manual (Catalog Number 5693-23) for
additional information.
Technology Description 12
Pulse oximetry is a non-invasive method of monitoring the oxygen saturation of
arterial blood. Oxygen saturation monitoring is intended to be used in a variety of
clinical situations including, respiratory therapy, anesthesia, the intensive care unit
(ICU) and neonatal (NICU) and pediatric (PICU) intensive care units.
The Model 520A Pulse Oximeter provides reliable continuous measurement,
display, and alerts for oxygen saturation (SpO>) and pulse rate. The monitor can be
powered from its rechargeable internal battery or from the AC Mains.
The Model 520A utilizes sensors containing two light emitting diodes (LEDs) and
a photodiode. Each LED emits a specific wavelength of light (660 and 940
nanometers) through a pulsating vascular bed to the photodiode. Oxygen saturated
blood absorbs different amounts of light at each wavelength as compared to
unsaturated blood. Therefore, the amount of light absorbed by the blood in each
pulse can be used to calculate saturation.
The Model 520A is calibrated to display “functional” saturation. This differs from
the “fractional” saturation value displayed by most co-oximeters. Functional
satüration is defined as:
HbO2
100 - (COHb + METHb)
НЪО? = Fractional Hemoglobin
COHb = Carboxyhemoglobin
METHb = Methemoglobin
Functional Saturation =
This can be considered to represent the amount of oxyhemoglobin as a percentage
of the hemoglobin that can be oxygenated. Dysfunctional hemoglobins (COHb and
METHb) are not included.

Section 1 Introduction
Pulse Rate is calculated by measuring the time interval between detected peaks of
the infrared light waveform. The inverse of this measurement is displayed as pulse
rate.
The oxygen saturation and pulse rate values are displayed on monitor’s displays.
The displayed values are updated once each second. Presence of a pulse is shown
as a waveform on the display and indicated audibly by a user selectable “beep”.
The Model 520A must be used in conjunction with SuperBright™ Sensors. These
sensors have an 8700 series part number (e.g., 8776 or 8791). An INCOMPATIBLE
PROBE display message will indicate a non-SuperBright™ Sensor (e.g., 86xx
series) is in use.
Conventions Used In This Manual 1.3
The following conventions will be used throughout this manual:
* Normal text will be shown in this type.
+ Message Center alerts and displays will be shown in this type.
+ The names of the front panel pushbuttons (keys) will be shown In this type.
Acknowledgments 1.4
SuperBright, Y-STRIP and Y-SENSOR are trademarks of Novametrix Medical
Systems Inc. SARAcap is a registered trademark of Allegheny International
Medical Technology, Inc. (PPG Biomedical Systems).

Patient Safety
The Model 520A Pulse Oximeter has electrically isolated inputs. Patient leakage
current flowing from the instrument to ground is limited to less than 10 pA at 120
V, 60 Hz. Patient isolation is greater than 10 MQ, 2500 V mms at 60 Hz. For
maximum patient and operator safety, the following procedures are recommended;
¢ Keep the Model 520A and its accessories clean.
+ Do not operate the Model 520A when it is wet due to spills or condensation.
e Do not operate the Model 520A if it appears to have been dropped or damaged.
Refer also to Warnings on page 4 and Cautions on page 5.

| 3 Warnings
Warning
Indicates a potentially harmful condition
that can lead to personal injury.
anesthetics. Use of this instrument in such an environment may present an
* Explosion Hazard: Do NOT use the Model 520A in the presence of flammable
/\ explosion hazard.
* Electrical Shock Hazard: Always tum the oximeter off before cleaning it. Do
NOT use a damaged sensor or one with exposed electrical contacts.
* Patient Safety: Extreme care should be exercised with neonates to assure
continued circulation distal to the sensor site after application.
ㆍ Failure of Operation: If the oximeter fails to respond as described, do not use
it until the situation has been corrected by qualified personnel.
¢ Data Validity: The Pulse Oximeter should NOT be used as a substitute for an
ECG monitor. The oximeter’s Pulse Rate display reflects the pulsatile flow
found at the patient extremity connected to the sensor. This rate can be affected
by many factors and may occasionally be “frozen”.
* Data Validity: Do NOT attach a sensor distal to a blood pressure cuff. Valid
data CANNOT be processed when the cuff is inflated. Attach the sensor to the
limb opposite to the site used for the blood pressure cuff.
+ Data Validity: Inaccurate SpO> and/or Pulse Rate measurements can be caused
by any of the following:
+ Incorrect application or use of a sensor
- ¢ Significant levels of dysfunctional hemoglobins such as
carboxyhemoglobin or methemoglobin
* Significant levels of indocyanine green, methylene blue, or other
intravascular dyes
+ Exposure to excessive illumination such as surgical lamps - especially ones
with a xenon light source, or direct sunlight
« Excessive patient movement, venous pulsations, electrosurgical
interference

4 Cautions
Caution
Indicates a condition that may lead to
equipment damage or malfunction.
+ Federal (U.S.A.) law restricts this device to sale, distribution, or use by or on the
order of a licensed medical practitioner.
e No tension should be applied to the sensor cable.
¢ Avoid storing the oximeter and sensors at temperatures exceeding -10° C and
+55° C (14° F and 131° F).
* Do not operate the monitor at ambient temperatures above 40° C or below 10° C
(50-104° F).
¢ Never immerse the monitor in liquids.
¢ Do NOT sterilize the monitor.
¢ Do NOT sterilize the Finger sensor.
* Electric Shock Hazard. Do NOT remove covers. Refer servicing to qualified
service personnel.
+ Connect the line cord only to a grounded hospital-grade outlet.

Front Panel
SATURATION 又
PULSE OXIME\ER OX YPLETH NOVAMETRIX
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PULSE RATE deatsimr
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1. Saturation% Di Area;
SpO2 and alert limit settings are
displayed here.
2. Pulse Rate Display Area;
Pulse Rate and alert limit settings
are displayed here.
3. Message Center, area where
system messages are displayed.
The functions of the softkeys (#4)
are annotated here.
4. Softkeys # 1-5; Softkeys 1-5 (left
to right) cause the action
annotated in the lower half of the
Message Center to occur.
5. Carrying Handle; monitor
carrying handle molded into case
Sensor Input Connector
Connect SuperBrightTM Sensors
here. Press tab on sensor
connector to remove sensor. Do
not twist connector.
7. Two Minute Silence Indicator;
Hluminates (yellow) when the
AUDIO key is pressed. SpO2 and
Pulse Rate alarms are silenced for
two minutes.
T
=
11 10
8. Audio key; Press and release
AUDIO to turn on/off the two
minute silence function. Press and
hold (approx. 3 seconds) AUDIO
to enable the Audio Off feature
(unless disabled via Options
Menu). Press and release to
disable Audio Off.
9. Audio Off Indicator; Flashes
(yellow) as a warning that the
audible alarms have been
disabled.
Alert Indicator; Flashes (red)
when an alert/alarm occurs.
Continues to flash until condition
corrected and ALERT RESET is
pressed.
11.
10.
; Press ALERT
RESET to disable any active alert
indicators. Alerts will reactivate if
alert condition still exists.
AC Power Indicator; Iluminates
(green) when the monitor is
connected to an AC (Mains)
power source and the rear panel
power switch is set to “I”.
12.
Figure 1. Front Panel Description
| pei
13.
14.
15.
16.
17.
Power key; Press POWER to tum
the monitor off and on.
Low Battery Indicator;
Hluminates (red) when
monitor is powered from its
internal battery and less than 30
minutes of battery power remain.
Red Alert Bar; Flashes (red) when
an alert/alarm occurs (unless
disabled via Options Menu).
Continues to flash until condition
corrected and ALERT RESET is
pressed (unless “unlatched”’ by
the user via the Options Menu).
Front Feet; Rubber tipped front
feet (2). Kickstand; Two position
kickstand (not shown) lifts front
of monitor for viewing from
above.
Contrast; Press and hold for
display contrast adjustment,
release when desired contrast is
obtained.
. Event; Press to mark an event in
trend memory.

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Rear & Top Panels
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Line Cord Clip; This clip can be
set around the line cord strain
relief so that the cord cannot be
pulled out of the connector.
Line Cord Connector, The AC
(Mains) line cord attâches to the
monitor here.
Fuse Compartment; The AC
(Mains) line fuse(s) are inside this
compartment. Pry open with
small screwdriver.
AC Mains Voltage; The currently
selected AC Mains input voltage
is identified here.
5.
6.
7.
AC Mains Power Switch; With pin “D” connector serves as the
switch in “O” position, AC Mains interface connector.
voltage does not enter monitor. , T ver
With switch in “|” position, AC 9 Top Cover - Monitor
Mains voltage allowed into ° Carrying Handle handl ? Ided int
monitor to power unit and/or carrying € mo in o case.
charge internal battery. 10. Waming Label, Explosion and
Rear Feet; Rubber tipped rear feet electrical shock warnings.
(2). 11. Patient Isolation Label; The
; Model 520A is Type BF
Serial Output Connector;
Serial (RS232) data output here equipment.
for use with Tele-Sat™ telemetry
system, optional analog output
module, and other RS232
interfaces. A female 25-
Figure 2. Rear and Top Panel Descriptions

7 Summary of
Operation
This section summarizes the operation of the Model 520A Pulse Oximeter. It is
intended as a quick reference and refresher for persons who have thoroughly
reviewed the Model 520A User's Manual (PN: 5693-23). Persons unfamiliar with
the Model 520A should thoroughly examine the User's Manual before referencing
the steps listed here.
1. If powering the monitor from the AC line voltage; Connect the line cord to the
monitor and plug into a properly grounded 3-wire outlet. Set the rear panel
power (Mains) switch to the | (on) position.
2. Press the front panel POWER key to turn the monitor on. Verify the Message
Center displays Connect SPO2 Probe after the self-tests are complete.
3. Use the Menu System to modify the operation of the monitor to best suit your
application. The Menu System menus include:
* ALRT softkey - Use SEL to select SpO2 or Pulse limits, then use the T or
4 to set the limit to the desired value. Note that the monitor will maintain
a spread of at least 5 digits between the upper and lower limit values.
+ TRND softkey - enters Trend mode and draws trend memory on display.
* MENU then AUDIO softkeys - Select Pulse to turn on/off and control the
volume of the audible beep with each detected pulse. Select ALERT to
control alert volume.
e MENU then AVG - Select either 2 second or 8 second SpO2 averaging
time.
・ MENU then LITE softkeys - toggles backlight between bright and dim.
47 Verify that the SpO» and Pulse Rate alert limit settings are consistent with
your monitoring application.
5. Connect a SuperBright™ (87xx series) sensor to the front panel input. Apply
the sensor to the patient.
6. Check that within several seconds the patient’s SpO> and Pulse Rate are
displayed on the monitor.
7. As necessary, refer to the appropriate sections within the User's Manual for
detailed operating instructions and explanations.

Menu Tree
Each menu within the Model 520A Pulse Oximeter is diagramed on the following
pages.