Novametrix Medical Systems TIDAL WAVE 610 User manual

HAND-HELD
CAPNOGRAPHY MONITOR
Service Manual
Model 610
April 17, 2000
Catalog No. 6700-90-01
Novametrix Medical Systems Inc.
PO Box 690
5 Technology Drive
Wallingford, Connecticut, U.S.A. 06492

Rev. 00 M610 Service Manual
iii
Contents
Safety ..................................................................................................... 1
Introduction ........................................................................................... 3
Indication for use .................................................................................. 3
Operational Overview ........................................................................... 3
Configuration Menu ...................................................................... 4
Theory of Operation ............................................................................. 7
2738 Main Board .................................................................................. 7
System Memory ......................................................................... 10
Serial Communications ..............................................................10
User Interface Control Circuitry .................................................. 11
Real Time Clock, Power on RESET Generation and Glue Logic .......12
CO2 System Analog Subsections ......................................................12
CO2 Pulser Source Drive ...........................................................12
Capnostat Case and Detector Heater Control ...................................14
CO2 Input Signal Path ....................................................................... 15
Capnostat Interface ............................................................................15
Barometric Pressure Circuitry .................................................... 15
Power Supply and Battery Charger .................................................... 16
2737 Board ................................................................................17
Functional Tests .................................................................................19
Equipment Required ..........................................................................19
Procedure ...........................................................................................19
Accuracy Tests ................................................................................... 21
Equipment Required ..........................................................................21
Test Procedure ...................................................................................21
Electronic Tests .................................................................................. 25
Equipment Required ..........................................................................25
Test Procedure ...................................................................................25
Safety Testing .................................................................................... 28
Maintenance ........................................................................................ 29
General .............................................................................................29
Maintenance Schedules ..................................................................... 29
Cleaning and Sterilization ..................................................................30
Monitor .......................................................................................30
CAPNOSTAT CO2Sensor .........................................................30
Single Patient Use Airway Adapters ..........................................30
Battery and AC Operation ..................................................................30

Rev. 00 M610 Service Manual
iv
Battery Indicator ......................................................................... 31
Rechargeable Batteries ............................................................. 31
AA Lithium Batteries ..................................................................32
AC wall adapter/charger (External DC supply) ..........................32
Removing and installing the battery ...........................................33
Assembly Exchanges ......................................................................... 33
Disassembling the Monitor .........................................................33
Reassembling the monitor .........................................................36
Serial Communications/Power Interface Connector ..........................36
Software Update Instructions ............................................................. 37
Equipment Required ..................................................................37
Setup .......................................................................................... 37
Procedure .................................................................................. 37
Display Status Messages ................................................................... 39
System Messages ......................................................................39
Battery Status and Alerts ...................................................................41
Status Messages and Codes .....................................................41
Specifications .....................................................................................43
Monitor Specifications ........................................................................43
Physical ...................................................................................... 43
Monitor and CAPNOSTAT CO2Sensor .....................................43
Symbol Descriptions ..................................................................44
Accessories ......................................................................................... 45
Parts .....................................................................................................47
Drawings and Schematics ................................................................. 55

Rev. 01 Model 610 Service Manual
v
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 guaranteesother 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.
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 1998, 2000 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.
Novametrix reserves the right to change specifications without notice. TIDAL WAVE is a trademark and
CAPNOSTAT is a registered trademark of Novametrix Medical Systems Inc.
Declaration of Conformity with European Union Directive
The Authorized Representative for Novametrix equipment is:
D.R.M. Green
European Compliance Services Limited
Oakdene House
Oak Road
Watchfield
Swindon, Wilts SN6 8TD
Service Department
For factory repair service, call toll free
1-800-243-3444
In Connecticut, call Collect [phone]
FAX [phone]
http://www.novametrix.com
Email [e-mail]

vi
Model 610 Service Manual Rev. 01
Revision History
00 Release 23-Mar-00
01 R-N746 17-Apr-00
Service Policy
Novametrix Medical Systems Inc. will provide Warranty Service Support to its customers within 48
hours of receiving a telephone request for technical support. This 48 hour period begins once a service
request is placed through the Factory Technical Support Department in Wallingford, Connecticut.
Novametrix provides factory direct technical support to its customers through a technical support group
located in Wallingford, Connecticut and company service representatives located throughout the United
States. All Technical Support for Novametrix products is provided “Factory Direct”.
Novametrix provides 24 hour a day technical support accessibility via telephone numbers (800) 243-
3444 or [phone]. After hours technical support requests (before 8:00 AM and after 5:00 PM
Eastern Time) will be responded to promptly by the Technical Support On-Call staff. It is suggested that
any person calling in for technical support have the inoperative equipment available for preliminary
troubleshooting as well as product identification. Novametrix reserves the right to repair or replace any
product found to be defective during the warranty period. Repair may be provided in the form of
replacement exchange parts or accessories, on-site technical repair assistance or complete system
exchanges. Repairs provided due to product abuse or misuse will be considered “non-warranty”and
invoiced at the prevailing service rate. Any replaced defective material is expected to be returned to
Novametrix within 10 days of being provided in order to avoid additional charges. Exchanged material
should be returned promptly and directly to Novametrix using the return paperwork and shipping label(s)
provided. Transferring return materials to local sales or dealer representatives does not absolve return
responsibility.
Novametrix manufactures equipment that is generally “user serviceable”and can usually be repaired
with the replacement of a plug-in electro-mechanical assemblyby the clinical end user. When repair parts
are provided, the recipient can call into Novametrix for on-line replacement assistance and repair
assurance. In the event a replacement part requires increased technical capability, Technical Support may
request Biomedical assistance, provide on-site technical support or complete replacement equipment. If
the customer requires the return of their original product, the exchange material will be considered
“loaner material”and exchanged again after the customer equipment is repaired.
Novametrix promotes customer participation in warranty repairs should they become necessary. This
program allows for customer training and a smooth transition into self-maintenance after warranty, which
can provide substantial cost savings on repairs throughout the product’s life.
The Novametrix Technical Support Department can provide technical product support at a level
appropriate to most customers protocol and budget requirements. Please contact the Technical Support
Group at Novametrix for additional information.
Additional Novametrix Technical Support Programs
•Focus Series Technical Training Seminars
•Test Equipment and Test Kits
•Service Contract / Part Insurance Plans
•On-Site Technical Support
•24 hr. telephone support
•“Demand Services”
Flat rate parts-exchange,
Flat rate return for repair
Time and Material,
Full warranty, discounted replacement sensors

Rev. 01 Model 610 Service Manual
1
Section 1
Safety
The
TIDALWAVE
handneld capnograph is electrically isolated. Patient leakage current flowing from the
instrument to ground is limited to less than 100 uA.
For maximum patient and operator safety, you must follow the following warnings and cautions.
•Explosion Hazard: Do NOT use the monitor in the presence of flammable anesthetics. Use of this
instrument in such an environment may present an explosion hazard.
•Electrical Shock Hazard: Always turn the monitor off and disconnect the external DC power
source before cleaning it. Do NOT use a damaged sensor or one with a damaged cable. Refer
servicing to qualified service personnel.
•Failure of Operation: If the monitor fails to respond as described, do not use it until the situation
has been corrected by qualified personnel.
•Do not operate the monitor if it appears to have been damaged.
•Never sterilize or immerse the monitor in liquids.
•The monitor does not alert for NO RESPIRATION if the airway adapter is removed from the
CAPNOSTAT CO2sensor.
•Do not position the CAPNOSTAT CO2sensor’s cable in a manner that may cause entanglement or
strangulation.
•Use the external battery charger in non-patient areas only.
•Do not apply tension to the sensor cable.
•Federal (USA) law restricts this device to sale by or on the order of a licensed medical practitioner.
•Use only a Novametrix approved power supply. Use of any other power supply may damage the
Tidal Wave and void the warranty.
•The Tidal Wave is not intended to be used as a primary diagnostic apnea monitor and/or recording
device.
•Refer servicing to qualified personnel.
•Never sterilize or immerse the monitor in liquids.
•Do not sterilize or immerse the sensor except as directed in this manual.
•Do not store the monitor or sensors at temperatures below 14°F (-10°C) or above 131°F (55°C).
•Do not operate the monitor or sensor at temperatures below 32°F (0°C) or above 104°F (40°C).
•Where electromagnetic devices (i.e., electrocautery) are used, patient monitoring may be interrupted
due to electromagnetic interference. Electromagnetic fields up to 3 V/m will not adversely affect
system performance.
WARNINGS
Indicates a potentially harmful condition that can lead to personal injury.
CAUTIONS
Indicates a condition that may lead to equipment damage or malfunction.
!
!

Section 1
2
Model 610 Service Manual Rev. 01
•The Tidal Wave monitor is intended for operation with Novametrix Single Patient Use airway
adapters.
•Certain rebreathing circuits, or the presence of artifact such as cardiogenic oscillations, may cause
the monitor to react to non-respiratory CO2fluctuations as if they were breaths. This condition
affects only the RESP (respiration) numeric values on the display.
•Refer to the User’s Manual (Cat. No. 6700-23) foradditional operational information.
•Operating the TIDAL WAVE below 50°F (10°C) will result in longer warm-up time and reduce
battery life.
•Components of this product and its associated accessories which have patient contact are free of
latex.
NOTES
Indicates points of particular interest or emphasis for more efficient or convenient operation.

Rev. 01 Model 610 Service Manual
3
Section 2
Introduction
The TIDAL WAVE hand-held capnograph from Novametrix is designed to monitor CO2whenever
capnography is required. The monitor combines full graphics capabilities, a no-respiration alert and
rugged CAPNOSTAT CO2sensor technology.
2.1 Indication for use
The TIDAL WAVE capnograph is a hand-held non-invasive CO2monitor specifically designed for short
term monitoring during transport, emergency, anesthesia, post anesthesia recovery, respiratory care and
intensive care.
2.2 Operational Overview
KEYS AND INDICATORS
Key Operator Action Function
1Press
Switches power on/off.
Capno
g
ram available immediately after self test, fully
operational in 60 seconds.
2 Press Selects Capno
g
ram (waveform) or trend display.
3
Press Silences audible alerts for two minutes. Press a
g
ain to
deactivate. Also resets (cancels) audio if pressed durin
g
an active alert (audio will not alert for the duration of the
NO RESPIRATION event that was silenced).
Pressandholdfor2
seconds Silences audible alerts until the key is pressed a
g
ain and
held. This function is reset upon the next power-up.
NOTE: -Refer to alert indicator below.
-Key inactive if audio disabled in confi
g
uration menu.
-The monitor may be factory confi
g
ured as to not allow the audio off
function (two minute silence is still available).
4
Press Sets display back li
g
ht off/on.
Press and hold Chan
g
es contrast/viewin
g
an
g
le of display (chan
g
es one
step every second).
5Press, then follow
screen instructions Chan
g
e application mode: adult/pediatric or neonatal
airway adapter use.
Pressandhold ,thenpress
before releasin
g
Displays CONFIGURATION screen (Select compensation
for N2O and hi
g
h O2, CO2scales, etc.).

Section 2
Operational Overview
4
Model 610 Service Manual Rev. 01
2.2.1 Configuration Menu
A CONFIGURATION menu is provided on the TIDAL WAVE in order to allow customizing of various
settings. To access the CONFIGURATION menu, press and hold the NEO key, then, simultaneously
press and hold the Backlight key until the CONFIGURATION screen is displayed. The grid on the
screen corresponds to the following chart, which indicates the available selections:
*-default settings
Changing CONFIGURATION settings:
Press the Waveform key to select among columns 1 through 8 (Gas comp., Waveform scale, etc.).
Indicators Function/Meanin
g
AGreen; batter
y
is full
y
char
g
ed.
Slow flashin
g
y
ellow; batter
y
power is low.
Fast flashin
g
red; batter
y
is exhausted (10 - 15 minutes monitor time left).
B Illuminated when "external" power is connected.
CStead
y
y
ellow: audio silenced for 2 min., no alert in pro
g
ress.
Flashin
g
y
ellow: audio silenced (no alert in pro
g
ress).
Flashin
g
red and
y
ellow: alert in pro
g
ress; audio is off or 2 minute silence.
D Illuminates when in NEO mode (see #5 above).
Icons Function/Meanin
g
Audible alert silenced for two minutes.
Breath bar. Gives real time indication of breaths.
Status indicator. Numbers 1-8 indicate specific conditions.
Neonatal icon. Used to indicate neonatal mode selected.
Adult icon. Used to indicate pediatric/adult mode selected.
Exit CONFIGURATION or time/date screen.
Set time/date. Press from CONFIGURATION screen to set time/date.
Indicates back li
g
ht ke
y
.
Trend screen icon. Displa
y
ed in Trend screen.
Sensor not up to temperature icon. Displa
y
ed when performin
g
an adapter
zero and the sensor is not at operatin
g
temperature.
Breaths detected icon. Displa
y
ed when performin
g
an adapter zero and the
monitor detects breaths.
Gas
Compen-
sation
Waveform
Scale
Waveform
Speed
NO RESP
Time
CO2Units
Alert
Volume
RS232
Interface
Waveform
Fill
12345678
*Room air Small Slow *20 seconds *mmHg Disabled *NovaCOM *Unfilled
O2>60% *Medium *Medium 40 seconds kPa *Low Reserved Filled
N2O >60%
balance O2Large Fast 60 seconds % *High --

Operational Overview
Section 2
Rev. 01 Model 610 Service Manual
5
Press the Alert key to change the setting of the selected column.
Press the NEO key to exit the CONFIGURATION menu and return to normal monitoring mode
(selections will be saved).
When formatting, the selected column is described on the first line of the text at the top of the screen. A
flashing, filled box indicates the current setting. The setting is described on the second line of text at the
top of the screen.
If CO2units are attempted to be changed after data has been collected a message warning that trend
memory will be erased is displayed. To change units and erase trends press the key a second time.
NOTE
Press to exit
Selects column Changes settings of
Press to set time/date
Displays selected setting
selected column

Section 2
Operational Overview
6
Model 610 Service Manual Rev. 01
[This page intentionally blank.]

Rev. 01 Model 610 Service Manual
7
Section 3
Theory of Operation
The TIDAL WAVE is a microprocessor-based handheld instrumentthat measures the clinical parameters
of CO2production and respiration rate. The system contains all the circuitry necessary for displaying
patient information gathered from the CAPNOSTAT®sensor. The theory of operation of the TIDAL
WAVE is explained in detail in the subsections that follow.
3.1 2738 Main Board
For circuit diagrams of the digital section described below, refer to sheet 1 of the Main Board (2738-03)
schematics. Embedded control for the system is provided by IC1, a Motorola MC68332 integrated
microcontroller. In addition to a full 32-bit Central Processing Unit (CPU), this device also contains
circuitry for system clock generation, peripheral chip selectgeneration, data control, interrupt generation,
a sophisticated timing co-processor, synchronous and asynchronous serial communication. In general,
functional signals are grouped together into ports, and each signal can be independently programmed by
software to be its pre-defined port function or as discrete I/O. Additionally, the functionality for several
ports (Port C, E and F) can be pre-defined by the state of the data bus on system power-up. A special
“background mode”port allows the device to be controlled by an external source for system debugging
and testing. Also integrated on-chip are several activity monitors, as well as a software watchdog to
ensure proper device and system operation. Refer to Table 1.
Table 1. CPU Port Functions
Port Defined Function Functionality Control, Data Bus Control
(Alt Functions: D pulled low)
TPU
16 Channels Timing Signal Generation Each channel independently user programmable as TPU function or as
Discrete I/O
QSM
4 Synchronous Serial
Chip Selects & one
asynchronous
serial channel
Serial Communications Port:
QSPI: Queued Serial Peripheral
Interface
SCI: Serial Communications
Interface
QSPI chip selects independently user pro-
grammable, can be used as
Discrete I/O ordecoded to create up to 16
chip selects. SCI transmit can be pro-
grammed as Discrete I/O
Background Mode System debugging Allows an appropriate external device to
control the microprocessor and system
C Chip Selects D0: CSBOOT* Data Width, 8 or 16-bit
D1: CS0*-CS3* or BR*,BG*,BGACK*
D2: CS3*-CS5* or FC0-FC2
D3-D7: CS6*-CS10* or A19-A23
E Bus Control D8: Control Signals or Discrete I/O
F MODCK and Interrupts D9: MODCK & IRQ or Discrete I/O

Section 3
2738 Main Board
8
Model 610 Service Manual Rev. 01
The maximum operating frequency of the integrated processor is 16.78 MHz. The operating frequency
is software selectable and generated by an internal VCO operating from Y1, a 32.768KHz watch crystal.
The Timing Processor Unit (TPU) co-processor of the MC68332 provides timing generation derived
from the system clock. This feature is utilized to control the precise timing required for the acquisition
of the End Tidal Carbon Dioxide (etCO2) signals.The TPU is also use to generate the PWM (pulseWidth
Modulation) control for the CAPNOSTAT case and detector heaters, generate clock output for the LED
backlight, monitor keypanel input, generate the DAC load pulse, as well as provide the frequency
generation for the audio tones. See Table 2.
Ferrite and L-C filters and 100pF capacitors have been placed on selected microprocessor signals with
fast rise and fall times (including timing, clock, and address lines) in order to help reduce and suppress
the radiation of electro-magnetic interference (L1-L6, & C154-C159). In addition, good EMI/EMC
design techniques have been incorporated in the component layout and printed circuitboard manufacture.
Table 3 lists the chip select, control and discrete I/O functions for the TIDAL WAVE system module. On
power-up, Ports E and F are programmed as discrete inputs by pulling down their controlling data lines,
DB8 and DB9. After power-up, the software sets up each pin function individually and performs a series
of self tests to check the integrity of the system. The state of configuration inputs on Port E (TST*,
CNEG0*, CNEG1* and JP0*) are read. These inputs allow the software to identify different operating
states such as Test Mode, or different hardware configurations. After the initialization period is complete
Table 2. TPU Timing Generation for the etCO2subsystem
Signal Name Function / Timing
CO2AZ Auto Zero Clears the Sample/Hold circuitry prior to data acquisition.
Active High, 90 us
CO2PWENB Pulse Width Enable Defines the active time for both phases of the bipolar source
pulse, used for pulse width protection circuitry.
Active High, 830 us
SRCDRV0 Source Drive 0 First source drive signal.
Active High, 405 us
CS*/H Current Sample/Hold Enables circuitry for source current measurement. Sample is
taken when SRCDRV0 is active.
Low = Sample, 90 us, High = Hold
SRCDRV1 Source Drive 1 Second source drive signal delayed for 30 microseconds after
SRCDRV0 ends.
Active High, 395 us
SS*/H Signal Sample/Hold Enables circuitry for CO2and Reference channel data
acquisition.
Low = Sample, 90 us, High = Hold
CASEPWM Case Heater PWM PWM control for the case heater servo
DETPWM Detector Heater
PWM PWM control for the detector heater servo
SW1 - SW4 Switch1 through
Switch4 Membrane keypanel input
TOUT1 Tone Generation Variable frequency outputs to generate system audio
BACKLITE LED Backlight 2kHz Frequency generated to modulate the backlight in order
to reduce power consumption.
DACLD* D-A Load Pulse When asserted, all 4 channels of the DAC latches are
simultaneously updated with the contents of the input latches.

2738 Main Board
Section 3
Rev. 01 Model 610 Service Manual
9
and all system functions have been set, the LED output toggles at a 1Hz rate switching transistor Q3
which drives the status LED D3, indicating that the system is ready for operation.
Table 3. Chip Select, Control and Discrete I/O
Port Pin Functions System Signal
Name I/O Comments
CD0 pulled low, D1-D7 pulled high,Pins are
Chip Select on power-up
CSBOOT** BOOTCS* O Program PROM Chip Select
Byte wide mode, (8-bits) D0 = LOW
CS0* / PC0 / BR* SRAMWR* O SRAM Write Enable
CS1*/ PC1 / BG* TP15 O Test Point Available For Expansion Or De-
bugging
CS2* / PC2 /
BGACK* SRAMRD* O SRAM Read Enable, Byte Mode
CS3* / PC3 / FC0 ROMWR* O FLASH PROM Write Enable, Byte Mode
CS4* / PC4 / FC1 DISPCS1* O LCD Chip select #1
CS5* / PC5 / FC2 DISPCS2* O LCD Chip select #2
CS6* / PC6 / A19 LEDCS* O Chip select for front panel LEDs
CS7* / PC7 / A20 RTCCS* O Real Time Clock Chip Select
CS8* / PC8 / A21 ROMWREN O
Port C Discrete Output, prevents uninten-
tionalwritestoFLASHEPROM.Thissignal
mustbeassertedbeforeROMWR*inorder
to overwrite the flash.
CS9* / PC9 / A22 PROFILE* O Enablessoftwareprofiling dataoutput latch
CS10* / ECLK /
A23 ECLK O Enable Clock for the Liquid Crystal Display
ED8 pulled low, Discrete I/O on power-up
DSACK0* / Port
E0 TST* I Initiate System TEST if Low
DSACK1* / Port
E1 DS1* I Data and Size Acknowledge 1*
AVC* / Port E2 CNFG0* I Configuration Switch 0
RMC* / Port E3 CNFG1* I Configuration Switch 1
DS* / Port E4 DS* O Data Strobe
AS* / Port E5 AS* O Address Strobe
SIZ0* / Port E6 JP0* I Hardware Jumper Mode Select 0
SIZ1* / Port E7 JP1* I Hardware Jumper Mode Select 1
R/W* RD* O Data Read Strobe
WR* O Data Write Strobe

Section 3
2738 Main Board
10
Model 610 Service Manual Rev. 01
3.1.1 System Memory
An 8-bit wide data path is used for FLASH PROM and SRAM transfers. Program code storage is
contained in a 1-Meg 5V FLASH or EEPROM (IC3) device. The FLASH PROM is protected from
unintentional overwrites of the program code by transistor Q1 and the ROMWREN signal. The
ROMWREN line must be high prior to writing new code into the FLASH devices. Volatile data storage
is contained in the SRAM (IC4). The SRAM is powered by a 2.5 Volt level (VBACK) when main power
is removed from the system. This allows non-volatile data storage when the monitor is off. Capacitors
C149 and C150 retain the data for approximately one minute during quick battery changes. During the
battery back-up state, transistor Q2 keeps the CS1* control of the SRAM inthe inactive state.This forces
the data bus to a high impedance state, isolating the SRAM from the rest of the system. True non-volatile
storage for system parameters is provided by a serial EEPROM (IC2).
3.1.2 Serial Communications
Reference page 6 on schematic.
The on-chip asynchronous serial communications interface (SCI) channel is contained in the MC68332.
The signals are level shifted to standard RS232 levels by IC29 which is a Dual RS232 Communications
Driver/Receiver. The transmitters in the RS232 level shifter are under software control to minimize the
patient leakage current to the rear panel connector J101 when communication is not being used. The
signal COMMPWR controls the transmitters operation and is derived from IC11 pin 14 (schematic page
2). The serial connection to external nonpatient contact devices is electrically isolated from the patient
through the CAPNOSTAT airway adapter. Connector J101 is designed to interface with external devices
when placed in the base station. There is a 4 pin connector (J403) available for test and service which
offers an internal connection to the RS232 communications. The data signals ASRxD and ASTxD are
FD9 pulled low, Discrete I/O on power-up
MODCK / Port F0 LED O LED CPU Activity Indicator
IRQ1* / Port F1 AUD_EN O Audio Enable Signal
IRQ2* / Port F2 CASEOT O Case Heater Over Temperature Shut
Down
IRQ3* / Port F3 DETOT O Detector Heater Over Temperature Shut
Down
IRQ4* / Port F4 EXTDCIN I Indicates externalAC MAINS power opera-
tion
IRQ5* / Port F5 PWRKEY I Power Key Status Input
IRQ6* / Port F6 I/O Spare I/O
IRQ7* / Port F7 NMI I Non-Maskable Interrupt
Table 3. Chip Select, Control and Discrete I/O
Port Pin Functions System Signal
Name I/O Comments

2738 Main Board
Section 3
Rev. 01 Model 610 Service Manual
11
logic level signals and are diode protected against over voltage by D38 and D35 should IC29 breakdown
from ESD. Refer to the table below for the pinout of J101.
3.1.3 User Interface Control Circuitry
Refer to schematic page 2.
The user interface features a 64 row by 128 column Liquid Crystal Display (LCD) module with an LED
backlight. Patient and system information is presented in both graphical and textual formats organized to
fit into a few simple screen configurations. A 5-switch membrane keypanel is provided for operator entry
of screenselection, calibration, adapterselection, display control,unit power, anduser configuration. The
user interface also contains four LEDs which represent various system conditions, such as input power
status (AC or Battery), adapter mode selection and alarm state. Control of the user interface is provided
by the LEDCS* chip select signal together with the TPU input signals from the microprocessor. TP9 thru
TP12 (SW1-SW4 respectively) are input buffers which read in the present state of the membrane keys.
Depressing a key causes the signal line to be pulled low in contrast to its normally high state. IC11
provides a latched output for controlling the status LEDs. The LCD backlight is a series of LEDs which
are driven by the TPU (BACKLITE) signal in order to lower the LCD backlight power requirement and
is activatedby the backlight membrane key. The BACKLITE signal is a 2kHz logic level signalgenerated
by TP14 which modulates the LED backlight through FET switch Q5. Thissignalis capacitively coupled
by C30 in order to prevent the backlight from remaining on in the event of a system failure. Reference
page 6 on schematic. Contrast control for the LCD is provided by DAC IC36 and amplifiers IC45A and
IC35B. When the CPU detects a press and hold of the backlight membrane key, the CPU sends a digital
ramp input to the DAC which causes the its output to change accordingly. Inverting amplifier IC35B
controls the base current into transistor Q18, which changes the level of the display contrast voltage,
VDISP.
Refer to schematic page 6.
An audio frequency tone is generated by the TPU processor of the MC68332 (TOUT1). This signal is fed
into the reference input of the 8-bit DAC IC36, providing a means for attenuating the signal under CPU
control. From the DAC, the signal (TOUT) is amplified by IC35A and Q4 which drives the system
speaker (LS1) to produce system audio. The audible signal can be disabled by the AUD-EN line. When
AUD-EN is high, Q22will be on, effectively grounding the input to IC35A, preventing any audiblesignal
from sounding.
Table 4: Power/Communications 6-pin modular connector J101 (rear panel).
Pin Number Signal Function
1 RxD Internal MC68332 UART Receive, RS232 Signal, Level Shifted
2 TxD Internal MC68332 UART Transmit, RS232 Signal, Level Shifted
3 DGND Digital Ground
4 DGND Digital Ground
5
6 +VCHG External DC input supply to power unit and battery charger

Section 3
Real Time Clock, Power on RESET Generation and Glue Logic
12
Model 610 Service Manual Rev. 01
3.2 Real Time Clock, Power on RESET Generation and Glue Logic
Reference sheet 2 on schematic.
Timekeeping for date, and time stamping of patient trend information, is provided by IC9. This device
contains a built-in crystal for precise time and date measurement. In the absence of digital power, the
timekeeping function is maintained by the battery backed-up supply, VBACKUP.
On power-up, the system is forced into a "Reset" state by IC6 (Sheet 1). When the supply voltage VDD,
attains a value approaching 1V, the SRST* line is asserted to prevent undefined operation. IC6 also
provides supervision over the VDD logic supply. If the logic supply falls below 4.55V ±120mV then IC6
generates a reset condition until the supply returns to a safe level. Inverter IC5 is used to generate the
active high RESET signal.
The TIDAL WAVE makes use of the high level of integration offered by the MC68332. Therefore, the glue
logic required is a minimum. Chip selection for the serial peripherals is provided by the queued serial
module (QSM) (PCS0-PCS3) of the microprocessor IC1 while parallel interface peripherals are selected
by the internal chip select registers of Port C (BOOTCS* and CS0*:CS10*) (see schematic sheet 1).
3.3 CO2System Analog Subsections
3.3.1 CO2 Pulser Source Drive
Refer to schematic page 3 and Table 2 of this document.
The source drive circuitry is designed to drive the source with a bipolar signal to prevent the migration
of charges within the source that may result from unidirectional electrical fields. The resistance of the
source is monitored constantly to ensure the integrity of the system by sampling the current through the
source while it is active.
The signals for the source drive are generated by the TPU co-processor in the MC68332, IC1. The
SRCDRV0 and SRCDRV1 lines are used to control the bipolar signal that drives the source. The
SRCDRV0 signal goes High as soon as the CO2AZ (Auto Zero) line goes Low and the CO2PWENB
(Pulse Width Enable) line goes High. The duration of SRCDRV0 is 405 us (micro-seconds), and drives
the source in the positive direction.The SRCDRV1 line drives the source with an opposite polarity signal
when High for the same duration. There is a 30 us delay from the time the SRCDRV0 line goes Low to
when the SCRDRV1 line goes High. This delay is to prevent the possibility of both SRCDRV0 and
SRCDRV1 being active at the same time, thus creating a low impedance path between the two supplies.
When SRCDRV0 and CO2INH (Inhibit) are High, the output of MOSFET Driver IC14A pin 7 will go
Low. This turns the P-Channel halfof MOSFET Q6 on. At the same time, the output of MOSFET Driver
IC15B pin 6 will be High, biasing on the N-Channel half of MOSFET Q7 on. With both Q6B P-Channel
and Q7A N-Channelon, current will flow from +VSRCthrough Q6B to thepositivesourceterminal, then
back from the source negative terminal through Q7A, through R110 to -VSRC. When SRCDRV0 returns
Low, both Q6B and Q7A are turned off and no current flows through the source. After the 30 us delay,
SRCDRV1 will go High. The output of IC15A pin 8 will go High, biasing the N-Channel section of
MOSFET Q6 on. The output of IC14B pin 5 will go Low, turning the P-Channel of Q7 on. Current will
now flow from +VSRC through Q7B to the source negative terminal, back from the source positive
terminal through Q6A and R110 to -VSRC. Current will cease to flow when SRCDRV1 goes Low. The
bridge circuit of Q6 and Q7 in effect switches the polarity of the drive signal of the source between
+VSRC and -VSRC. CO2PWENB also falls with the falling edge of SCRDRV1, signaling the end of
source activity.

CO2 System Analog Subsections
Section 3
Rev. 01 Model 610 Service Manual
13
When current flows through the source, it will also flow through current sensing resistor R110, creating
a differential voltage proportional to the source current:
VSRC = (VSR / RSR) * RS* AV(DA) where VSRC = voltage out of difference amplifier
proportional to current through the source element
= 24V +/- 0.625V
VSR = differential voltage across the source element
RSR = resistance of the source element
RS = resistance of the current sensing resistor
= 1 ohm
AV(DA) = difference amplifier gain
= 5
VSRC = [120 (Volts*Ohms) / RSR]
The voltage signal out of difference amplifier IC16B is level shifted through C36 and fed to the sample
and hold IC17A. A low level on the CS*/H (Current Sample and Hold) signal allows the source current
signal to be sampled. On the rising edge of CS*/H, the present voltage level of the source current signal
is held and appears at the input to channel A2 of the Analog to Digital Converter IC8 for processing by
the MPU. When CO2AZ is High, the input to the sample and hold of IC17A is grounded to discharge
any residual chargethatmay be on C36. Thisclears thesampleand hold outputfor the next measurement.
In order to prevent the source from being driven until the system is up and ready, protection circuitry
inhibits the source drive until enabled. During system power-up, the RESET line keeps Q8 on. This
causes the CO2INH line to be brought Low, preventing source pulses by pulling down SRCDRV0 and
SCRDRV1 through D8. Protection circuitry also guards against extended pulse width as well as
shortened duty cycle. On the rising edge of CO2PWENB, the trip point of IC18B is exceeded, allowing
C39 to charge through R114. If the SRCDRV signals do notturn the Source Pulser off within 200 us after
the 830 us pulse period, the trip point for IC18A will be exceeded, pulling the CO2INH line low, turning
the Pulser off. After the CO2PWENB signal returns Low, capacitor C41 discharges through R115,
keeping the output of comparator IC18B at the voltage acquired by C39. After approximately 10.4 ms,
C41 will have discharged below the comparator trip point. The comparator output goes low, discharging
C39 and the circuit is ready for the next source pulse cycle.

Section 3
Capnostat Case and Detector Heater Control
14
Model 610 Service Manual Rev. 01
3.4 CAPNOSTAT Case and Detector Heater Control
Refer to schematic page 4.
The temperature of the system directly affects its ability to accurately measure CO2and therefore must
be precisely maintained at a controlled value. Two separate heaters and control circuitry are used; one
regulates the temperature of the detectors for the CO2Data and Reference channels; the other regulates
the temperature of the transducer case (and loosely maintains the temperature of the airway adapter).
While thepurpose ofthe Detector heater is to keep the detectors'sensitivity to infrared radiation constant,
the function of the Case heater is to keep condensation from forming on the airway windows by elevating
the window temperature above the ambient airway temperature. Both heaters use an efficient Pulse-
Width Modulation scheme designed to decrease power consumption, with the PWM timing generated by
the TPU under microprocessor control. This control loop is run by the CPU which does the calculations
passes the duty cycle to the TPU. For the purpose of describing the regulation loop, the case heater
circuitry will be considered. The detector and case heater circuitry are identical.
Inside the CAPNOSTAT, a sensing thermistor is thermally connected to the heater module. Initially, the
CAPNOSTAT is at the ambient temperature and the resistance of the thermistor is large. A small current
flows through the signal path CASETHERM and only a small voltage is developed across R131. The
microprocessor programs the TPU to allow a maximum duty cycle of 90% to power the PWM heater
circuitry. This causes the heater control MOSFET Q13A to be pulsed on and off with a duty cycle that is
underdirect control of the program software. As the heaterwarms up the case,the thermistor's resistance
decreases, raising the voltage appearing at the input of the control loop. As described below, the MPU
looksat this output voltage and decreases the duty cycle of the PWM controlcircuitry, gradually reducing
the power output into the heater. When the desired temperature set point is reached, a balance is struck
between the energy delivered into the system and the heat flow out of the system.
The case thermistor is sensed by amplifier IC20A pin 3. The difference between the signal at the non-
inverting input and the reference appearing at the inverting terminal generates an error voltage
proportional to the sensed temperature at the amplifier's output:
eo(V) = [83.133V / (Rth+3.32K)] - 10.2V
where eo= amplifier output voltage
Rth = resistance of the thermistor
= 4.36933K at 45°C
Temp (°C) = 4.1288 (°C/V) * eo (T) V + 41.7321°C
where eo= amplifier output voltage at temperature T
This error voltage is low pass filtered by amplifier IC19A, sent to the ADC and processed by the CPU to
regulate the output pulses from the TPU. The TPU PWM signal is buffered by MOSFET Driver IC22B
and capacitively coupled to the gate of the heater drive MOSFET, Q13A. Capacitive coupling the signal
prevents a system fault that would allow the PWM to be stuck at a level that would cause too high of a
heater output. In the absence of a pulse, the gate drive will be pulled high, disabling the output to the
heater. The pulsed voltage signal out of the MOSFET is filtered by D15, L7, C52 and C54 to produce a
DC output level for the heater. Since the TPU generated PWM signal is based on the system clock, it is
synchronized with the generation of the source pulse timing. This minimizes the effect of any random
disturbance caused by the heater circuit on the detection of the CO2Data and Reference signals.
The error voltage out of amplifier IC20A also appears at the temperature watchdog comparator IC21A.
If the error voltage reaches a voltage equivalent to 56 degrees Celsius, the comparator trips, turning Q11
off. The gate of MOSFET Q10A is pulled high by R130, which turns it off and VHTR is prevented from
reaching the Source of transistor Q13A. The temperature of the sensor is also monitored by the MPU
which will disable the heater when a temperature of 50 degrees Celsius is exceeded. To shut off the heater,
the MPU asserts the CASEOT signal, turning Q12 on which turns Q11 and Q10A off, which in turn shuts
Q13A off.