Mindray Gas Module User manual

Service Manual Addendum

Gas Module II

™

Gas Module SE

™

Gas Module SE™ with Spirometry Gas Module 3

Service Manual Addendum

Gas Module II

™

Gas Module SE

™

Gas Module SE™ with Spirometry Gas Module 3

AION™ is a trademark of Artema Medical AB.

™

D-Lite

is a trademark of GE Medical Systems Information Technologies.

DRYLINE

™

is a trademark of Artema Medical AB.

Gas Module II

Gas Module SE

™

Nafion

Passport

Passport 2

Spectrum

is a trademark of Perma Pure Inc.

XG is a U.S. registered trademark of Mindray DS USA, Inc.

is a U.S. registered trademark of Mindray DS USA, Inc.

Spectrum OR

is a U.S. registered trademark of Mindray DS USA, Inc.

™

is a U.S. trademark of Mindray DS USA, Inc.

™

is a U.S. trademark of Mindray DS USA, Inc.

0070-10-0522 Gas Module Service Manual Addendum

Table of Contents

Introduction.................................................................................................................................................... v

Warnings, Precautions and Notes.....................................................................................................................vi

Warnings ......................................................................................................................................................vi

Cautions ........................................................................................................................................................ vii

Theory Of Operation......................................................................................................... 1 - 1

Gas Sampling System...................................................................................................................................... 1 - 2

Water Trap............................................................................................................................................. 1 - 3

Zero Valve and Absorber ......................................................................................................................... 1 - 4

™

Nafion

Tube ......................................................................................................................................... 1 - 4

Gas Analyzers ........................................................................................................................................ 1 - 4

Sample Flow Differential Pressure Transducer .............................................................................................. 1 - 4

Working Pressure Transducer.................................................................................................................... 1 - 4

Pneumatic Unit ........................................................................................................................................ 1 - 4

Connection Block..................................................................................................................................... 1 - 4

Occlusion Valve ...................................................................................................................................... 1 - 5

Sampling Pump and Damping Chamber..................................................................................................... 1 - 5

Anesthetic Agent Sensor .................................................................................................................................. 1 - 6

Gas Module II, Gas Module SE, and Gas Module SE with Spirometry ........................................................... 1 - 6

Gas Module 3 ........................................................................................................................................ 1 - 8

Sensor ..................................................................................................................................................... 1 - 11

Gas Module II, Gas Module SE, and Gas Module SE with Spirometry ........................................................... 1 - 11

Gas Module 3 ........................................................................................................................................ 1 - 12

CPU Board..................................................................................................................................................... 1 - 14

Gas Module II, Gas Module SE, and Gas Module SE with Spirometry ........................................................... 1 - 14

Gas Module 3 ........................................................................................................................................ 1 - 15

Board ...................................................................................................................................................... 1 - 16

Communication Interface Board........................................................................................................................ 1 - 17

Gas Module II, Gas Module SE, and Gas Module SE with Spirometry ........................................................... 1 - 17

Gas Module 3 ........................................................................................................................................ 1 - 18

Electrical Wiring Diagram................................................................................................................................ 1 - 19

Gas Module 3 Electronics ................................................................................................................................ 1 - 20

Power Supply ................................................................................................................................................. 1 - 22

Gas Module II, Gas Module SE, and Gas Module SE with Spirometry ........................................................... 1 - 22

Gas Module 3 ........................................................................................................................................ 1 - 23

Spirometry (Gas Module SE with Spirometry Only) Overview ............................................................................... 1 - 24

Measured Parameters .............................................................................................................................. 1 - 24

Measurement Principles............................................................................................................................ 1 - 25

PVX Measuring Unit ................................................................................................................................. 1 - 25

Specifications.................................................................................................................... 2 - 1

Performance Specifications .............................................................................................................................. 2 - 2

Gas Module II, Gas Module SE, and Gas Module SE with Spirometry ........................................................... 2 - 2

Gas Module 3 ........................................................................................................................................ 2 - 3

Gas Measurements ......................................................................................................................................... 2 - 6

Normal Conditions .................................................................................................................................. 2 - 6

Non-disturbing Gases .............................................................................................................................. 2 - 6

Disturbing Gases ..................................................................................................................................... 2 - 7

Gas Module 3 Interference Specifications................................................................................................... 2 - 7

...................................................................................................................................................... 2 - 8

......................................................................................................................................................... 2 - 9

O...................................................................................................................................................... 2 - 10

Anesthetic Agents .................................................................................................................................... 2 - 10

Accuracy specifications at conditions exceeding normal............................................................................... 2 - 12

Gas Module Service Manual Addendum 0070-10-0522 i

Table of Contents

ISO Mode Accuracy specifications for Gas Module 3 .................................................................................. 2 - 13

Patient Spirometry........................................................................................................................................... 2 - 15

Normal Conditions for Gas Module SE with Spirometry ............................................................................... 2 - 15

Accuracy specifications at conditions exceeding normal............................................................................... 2 - 16

Power Input Ratings......................................................................................................................................... 2 - 17

Environmental Conditions................................................................................................................................. 2 - 17

Gas Module II, Gas Module SE, and Gas Module SE with Spirometry ........................................................... 2 - 17

Gas Module 3 ........................................................................................................................................ 2 - 17

Physical Characteristics ................................................................................................................................... 2 - 18

Gas Module II......................................................................................................................................... 2 - 18

Gas Module SE....................................................................................................................................... 2 - 18

Gas Module 3 ........................................................................................................................................ 2 - 18

Agency Compliance........................................................................................................................................ 2 - 18

Gas Module II......................................................................................................................................... 2 - 18

Gas Module SE....................................................................................................................................... 2 - 19

Gas Module 3 ........................................................................................................................................ 2 - 19

Repair Information ........................................................................................................... 3 - 1

Introduction.................................................................................................................................................... 3 - 1

Safety Precautions........................................................................................................................................... 3 - 2

Troubleshooting .............................................................................................................................................. 3 - 2

General Troubleshooting Guidelines .......................................................................................................... 3 - 2

Gas Module Technical Troubleshooting ...................................................................................................... 3 - 3

Patient Spirometry Trouble Shooting........................................................................................................... 3 - 6

Exchange Program .................................................................................................................................. 3 - 7

Equipment and Special Tools Required .............................................................................................................. 3 - 8

Disassembly Instructions................................................................................................................................... 3 - 9

Gas Module II, Gas Module SE, and Gas Module SE with Spirometry ........................................................... 3 - 9

Gas Module 3 ........................................................................................................................................ 3 - 12

Mounting Hardware and Accessories................................................................................................................ 3 - 13

Passport XG/Gas Module Mounting .......................................................................................................... 3 - 13

Expert/Gas Module Mounting................................................................................................................... 3 - 15

Passport 2/Spectrum/Spectrum OR Gas Module Mounting .......................................................................... 3 - 17

Gas Module II/Gas Module SE Accessories ....................................................................................................... 3 - 21

Gas Module SE with Spirometry Accessories ...................................................................................................... 3 - 22

Gas Module 3 Accessories .............................................................................................................................. 3 - 23

Replacement Parts ............................................................................................................ 4 - 1

Introduction.................................................................................................................................................... 4 - 1

Available Replacement Parts and Sub-Assemblies ............................................................................................... 4 - 1

Exchange Program.......................................................................................................................................... 4 - 2

Replacement Parts Pricing Information ............................................................................................................... 4 - 2

Ordering Information ...................................................................................................................................... 4 - 3

Abbreviations................................................................................................................................................. 4 - 4

Isometric Drawing and Parts Lists ...................................................................................................................... 4 - 5

Calibration ....................................................................................................................... 5 - 1

Introduction.................................................................................................................................................... 5 - 1

Warnings and Guidelines................................................................................................................................ 5 - 1

Test Equipment and Special Tools Required........................................................................................................ 5 - 2

Power-Up Verification...................................................................................................................................... 5 - 2

Passport XG Configuration for Gas Module ................................................................................................ 5 - 2

Expert Configuration for Gas Module......................................................................................................... 5 - 3

Passport 2/Spectrum/Spectrum OR Configuration for the Gas Module .......................................................... 5 - 4

Gas Module 3 Pneumatic Leakage Test.............................................................................................................. 5 - 5

ii 0070-10-0522 Gas Module Service Manual Addendum

Table of Contents

Gas Module 3 Zero Reference Valve Test .......................................................................................................... 5 - 5

Calibration..................................................................................................................................................... 5 - 6

Passport XG Gas Calibration .................................................................................................................... 5 - 6

Expert Gas Module Calibration................................................................................................................. 5 - 8

Gas Monitor Calibration - Passport 2/Spectrum/Spectrum OR...................................................................... 5-10

Power Supply PC Board Calibration .......................................................................................................... 5 - 16

Patient Spirometry Calibration Measurement (Spectrum OR only)...................................................................5-18

Patient Spirometry Leak Test Verification (Spectrum OR Only)........................................................................ 5 - 20

Gas Module Leakage Current Checks................................................................................................................ 5 - 21

Preventive Maintenance.................................................................................................... 6 - 1

Preventive Maintenance Introduction ................................................................................................................. 6 - 1

Preventive Maintenance Schedule ..................................................................................................................... 6 - 1

Performance Verification.................................................................................................................................. 6 - 2

Perform as required, or at 6 month intervals................................................................................................ 6 - 2

Perform as required, or 1 Year intervals ..................................................................................................... 6 - 2

Patient Spirometry Leak Test Verification (Spectrum OR Only)........................................................................ 6 - 2

Mechanical / Physical / Visual Inspection ......................................................................................................... 6 - 2

Perform at 6 month intervals...................................................................................................................... 6 - 2

Consumable Item Replacement ......................................................................................................................... 6 - 2

Replace at 1 month intervals ..................................................................................................................... 6 - 2

Replace at 2 month intervals ..................................................................................................................... 6 - 2

Replace at 12 month intervals ................................................................................................................... 6 - 2

Replace at 24 month intervals ................................................................................................................... 6 - 2

Internal Adjustments/Calibration....................................................................................................................... 6 - 3

Perform at 12 month intervals or as required............................................................................................... 6 - 3

Patient Spirometry Calibration Measurement (Spectrum OR only)...................................................................6-3

Care and Cleaning of Gas Module................................................................................................................... 6 - 4

Gas Module II, Gas Module SE, and Gas Module SE with Spirometry ........................................................... 6 - 4

Gas Module 3 ........................................................................................................................................ 6 - 5

Gas Module Service Manual Addendum 0070-10-0522 iii

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iv 0070-10-0522 Gas Module Service Manual Addendum

Introduction Introduction

Introduction

The Gas Module is a companion to several Patient Monitors. It is capable of automatically identifying and measuring five anesthetic agents (Desflurane, Enflurane, Sevoflurane, Halothane and Isoflurane), as well as N sidestream sampling.

The following models are referenced in this manual: Gas Module II, Gas Module SE, Gas Module SE with Spirometry, and Gas Module 3. When information is common to all models, the generic name “Gas Module” is used. Information that is unique to a specific model is identified accordingly.

The system connects to the Patient Monitor via an RS232 connector.

A special “Y” shaped power cord is used to supply AC voltage to both the Gas Module and the Monitor power supply. All Gas Module data displays on the monitor screen. All user commands are entered on the monitor and then electronically transmitted to the Gas Module.

This addendum provides Gas Module information on theory of operation, specifications, repair, parts, calibration and preventive maintenance. For related information on the Patient Monitor, refer to the associated Service Manual and Operating Instructions.

O, CO2 and O2. The unit monitors all gases via

• Passport XG Operating Instructions

• Passport 2 Operating Instructions (Domestic)

• Passport 2 Operating Instructions (International)

• Expert Operating Instructions (Domestic)

• Spectrum Operating Instructions (Worldwide)

• Spectrum OR Operating Instructions (Worldwide)

NOTE: The Gas Module SE with Spirometry can only be used with

NOTE: The Gas Module 3 can only be used with Passport 2,

WARNING: Calibration gas is considered Dangerous Goods/Hazardous

the Spectrum OR monitor.

Spectrum, and Spectrum OR monitors.

Materials per I.A.T.A. and D.O.T. Regulations.

It is a violation of federal and international law to offer any package or over pack of dangerous goods for transportation without the package being appropriately identified, packed, marked, classified, labeled and documented according to D.O.T. and I.A.T.A. regulations. Please refer to the applicable I.A.T.A. Dangerous Goods Regulations and/or the Code of Federal Regulations 49 (Transportation, Parts 171-180) for further information.

Gas Module Service Manual Addendum 0070-10-0522 v

Introduction Warnings, Precautions and Notes

Warnings, Precautions and Notes

Please read and adhere to all warnings, precautions and notes listed here and in the appropriate areas throughout this manual.

A WARNING is provided to alert the user to potential serious outcomes (death, injury, or serious adverse events) to the patient or the user.

A CAUTION is provided to alert the user to use special care necessary for the safe and effective use of the device. They may include actions to be taken to avoid effects on patients or users that may not be potentially life threatening or result in serious injury, but about which the user should be aware. Cautions are also provided to alert the user to adverse effects on this device of use or misuse and the care necessary to avoid such effects.

A NOTE is provided when additional general information is applicable.

Warnings

WARNING: Always Remove Power from the Gas Module BEFORE

WARNING: Remove Power from the Gas Module BEFORE removing the

WARNING: If the water trap breaks or becomes damaged during

WARNING: The airway adapter and sampling line are intended for

WARNING: The water trap, sampling line, and airway adapter should

WARNING: To avoid high sampling flow with the Gas Module 3, do not

WARNING: Connect only approved gas sampling lines to the water

WARNING: The Gas Module must not be used with flammable

WARNING: The use of gas sampling accessories other than specified

Disassembly.

Enclosure.

operation, there is a risk that bacteria and/or mucus may contaminate the Gas Module.

single use only.

be disposed of in accordance with local regulations for contaminated and biologically hazardous items.

use Adult/Pediatric water traps and/or sampling lines with neonates.

trap.

anesthetic agents.

may cause significant measurement errors and patient risk.

WARNING: With the Gas Module 3, use only Neonate sampling lines

and water traps for Neonate patients. Do not use Neonate sampling lines and water traps for Adult/Pediatric patients.

WARNING: Do not allow the sampling tubing to become kinked.

WARNING: Do not reuse disposable devices.

vi 0070-10-0522 Gas Module Service Manual Addendum

Cautions Introduction

WARNING: Trace Gas Hazard – When using the optional Gas Module, a

WARNING: When monitoring CO

WARNING: Connection of the Gas Module exhaust port to the hospital’s

WARNING: Equipment not suitable for use in the presence of a

WARNING: Do not connect devices that are not specified as part of the

WARNING: Do not clean the Gas Module while it is on and/or

health hazard exists when trace amounts of vaporized anesthetic agents are chronically inspired by operating room personnel. See Appendix A in NFPA 56A on Inhalation Anesthetics. During any procedure where such agents are employed, the Gas Module exhaust output should be connected to a medical gas-scavenging system.

, connection from the exhaust port to the hospital’s waste gas-scavenging system is recommended to prevent exposure of hospital personnel to the patient’s respiratory sample.

waste gas-scavenging system is recommended to prevent exposure of hospital personnel to the patient’s respiratory sample. Vacuum (negative pressure) should not exceed 1 mmHg at the Gas Module exhaust fitting. Excessive scavenge vacuum may result in damage to the Gas Module’s internal pump.

flammable anesthetic mixture with air or with nitrogen or nitrous oxide.

system.

plugged in.

WARNING: The contents of the water trap should be handled as a

potential infection hazard.

Cautions

CAUTION: The internal sampling system of the Gas Module does not

need to be cleaned or sterilized. There is no reverse flow back to the patient. If the internal sampling system is suspected to be clogged or dirty, the module should be serviced by an authorized service person only.

CAUTION: If the dust filter for the fan cannot be cleaned or is

damaged, replace it with part number 0378-00-0040. Use of another type of filter may decrease the cooling effectivity and cause damage to the Gas Module.

CAUTION: Do not disinfect or open the water trap. Do not touch the

water trap membrane.

CAUTION: Dispose of the water trap in accordance with hospital policy.

Gas Module Service Manual Addendum 0070-10-0522 vii

Introduction Cautions

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viii 0070-10-0522 Gas Module Service Manual Addendum

1.0

Theory Of Operation

Contents of this chapter .................................................................... Page

1.1 Gas Sampling System ............................................................... 1-2

1.2 Anesthetic Agent Sensor ........................................................... 1-6

1.3 O2 Sensor ................................................................................ 1-11

1.4 CPU Board ................................................................................ 1-14

1.5 O2 Board ................................................................................. 1-16

1.6 Communication Interface Board ................................................ 1-17

1.7 Electrical Wiring Diagram ......................................................... 1-19

1.9 Power Supply ........................................................................... 1-22

1.10 Spirometry (Gas Module SE with Spirometry Only) Overview . 1-24

This Theory of Operation section provides block diagrams, a functional overview of the main components and the gas sampling / measurement principle for the Gas Module.

The Gas Module consists of the following main components:

• Gas Sampling System

• Anesthetic Agent Sensor

Sensor

•O

•CPU Board

•O

Board

• Communications Interface Board

• Power Supply

• Spirometry Module (PVX unit)

• Water Trap

• Internal Tubing

Gas Module Service Manual Addendum 0070-10-0522 1 - 1

Gas Sampling System Theory Of Operation

OUT

REF

Pneumatic unit

Pressure transducers

OUT

Damping chamber

Sampling pump

TPX unit

OUT

Connection block

Wate r trap

OM unit

Nafion tube

CO2 absorber

Nafion tube

1.1 Gas Sampling System

The sampling system draws in a patient sample to the analyzers at a fixed rate.

The gas sampling system draws patient sample into the module, and removes water and impurities from it in a water trap. The pump draws gas through the sampling line, through the water trap and into the gas measuring units. After the measurements, the gas is expelled through the exhaust port. The sample flow rates are as follows:

• For Gas Module II, Gas Module SE, and Gas Module SE with Spirometry, the sample flow rate is 200 ml/min.

• For Gas Module 3, the sample flow rate is 200 ml/min with the Adult/Pediatric water trap and 120 ml/min with the Neonatal water trap.

A number of flow restrictors are utilized to create a pressure difference with ambient pressure in the gas sensors.

A larger pressure difference makes the presentation of the gas concentration curves less sensitive to variations in the airway pressure thus meeting the accuracy requirements.

Refer to the FIGURE 1-1 and FIGURE 1-2 for the Gas Tubing Layout and Gas Sampling Component Block Diagram for Gas Module II, Gas Module SE, and Gas Module SE with Spirometry. Refer to the FIGURE 1-3 for the combination Gas Tubing Layout and Gas Sampling Component Block Diagram for Gas Module 3.

FIGURE 1-1 Gas Tubing Layout – Gas Module II, Gas Module SE, and Gas Module SE

with Spirometry

1 - 2 0070-10-0522 Gas Module Service Manual Addendum

Theory Of Operation Gas Sampling System

Sample

line

Zero

valve

Reference gas

Occlusion

valve

Room air

Pressure

Transducer

Filter

Pressure

Transducer

TPX

Pump

Absorber

Pump

Module

to O2

Sensor

from O2

Sensor

Purge

Sample In

DRYLINE

™

Water Trap

to EVAC

EVAC Outlet Connection

Purge Valve

Zero Valve

Pneumatic

Module

Gas

Measurement

Bench

Servomex

O2 Sensor

Sample

Patient

AION

™

FIGURE 1-2 Gas Sampling Component Block Diagram – Gas Module II, Gas Module SE,

and Gas Module SE with Spirometry

FIGURE 1-3 Combination Gas Tubing Layout and Gas Sampling Component Block

Diagram – Gas Module 3

1.1.1 Water Trap

™

water trap system.

Gas Module Service Manual Addendum 0070-10-0522 1 - 3

The sample is drawn through a sample line. Then gas enters the monitor through the water trap, where it is divided into two flows, a main flow and a side flow. The main flow goes into the analyzers. This flow is separated from the patient side by a hydrophobic filter. The side flow creates a slight subatmospheric pressure within the water trap which causes fluid removed by the hydrophobic filter to collect in the bottle.

The Gas Module 3 uses the DRYLINE

Gas Sampling System Theory Of Operation

1.1.2 Zero Valve and Absorber

The main flow passes through a magnetic valve before proceeding to the analyzers. This valve is activated to establish the zero points for the Anesthetic Agent and O2 Sensors. When the valve is activated, room air is drawn through the absorber into the internal system and the gas sensors. Paralyme is used as the absorbent. The Absorber is for Gas Module II, Gas Module SE, and Gas Module SE with Spirometry.

1.1.3 Nafion™ Tube

A nafion tube is used between the water trap and the zero valve to balance the sample gas humidity with that of ambient air. The tube will prevent errors caused by the effect of water vapor on gas partial pressure when the humid gases are measured after calibration with dry gases.

*Nafion is a trademark of Perma Pure Inc.

1.1.4 Gas Analyzers

After the zero valve and nafion tube the gas passes through the Anesthetic Agent and O2 Sensors. The oxygen sensor has two inputs. One input accepts the gas sample and the other draws room air for reference. The gas sample finally exits through the exhaust port on the rear of the unit. Refer to sections 1.2 and 1.3 for more information on the Anesthetic Agent and O

Sensors.

™

The Gas Module 3 uses an AION Oxygen Sensor. The AION must be a matched pair.

™

multigas analyzer and a Servomex Paramagnetic

multigas analyzer and Servomex Paramagnetic Oxygen Sensor

1.1.5 Sample Flow Differential Pressure Transducer

The sample flow differential pressure transducer (Gas Module II, Gas Module SE, and Gas Module SE with Spirometry) measures pressure drop across the O2 Sensor inlet restrictor and calculates sample flow from the pressure difference.

1.1.6 Working Pressure Transducer

The working pressure transducer (Gas Module II, Gas Module SE, and Gas Module SE with Spirometry) measures absolute working pressure between the Anesthetic Agent and O Sensors. It is used to detect situations which will post messages for occlusion and replace trap.

1.1.7 Pneumatic Unit

The pneumatic unit contains the zeroing valve, occlusion valve and tubing connections. There is a series of restrictors and chambers forming a pneumatic filter to prevent pressure oscillations in the pump from reaching the measuring units. Zeroing and occlusion valve connections to room air include a dust filter.

1.1.8 Connection Block

The connection block contains a sample gas outlet connector and an O2 Sensor reference gas inlet. The inlet is equipped with a dust filter.

1 - 4 0070-10-0522 Gas Module Service Manual Addendum

Theory Of Operation Gas Sampling System

1.1.9 Occlusion Valve

The valve (Gas Module II, Gas Module SE, and Gas Module SE with Spirometry) is activated when the sample line gets occluded. The main flow is diverted to the side flow of the water trap to help remove the occlusion faster.

1.1.10 Sampling Pump and Damping Chamber

The Gas Module II, Gas Module SE, and Gas Module SE with Spirometry gas sampling pump is a membrane pump that is run by a brushless DC motor. The gas flow rate is measured with a sample flow differential pressure transducer across a known restriction. The motor is automatically controlled to maintain a constant flow, even when the water trap ages and starts to get occluded. It also enables use of sample tubes with varying lengths and diameters.

The damping chamber is used to even out the pulsating flow and silence the exhaust flow.

The Gas Module 3 pump module is a low power, high reliability membrane pump and flow controller including preamplifier and pump power driver.

NOTE: Flow is never reversed towards the patient.

Gas Module Service Manual Addendum 0070-10-0522 1 - 5

Anesthetic Agent Sensor Theory Of Operation

Thermopile detectors

Temp sensor

Sample gas in

Sample gas out

Sample chamber

1.2 Anesthetic Agent Sensor

1.2.1 Gas Module II, Gas Module SE, and Gas Module SE with Spirometry

FIGURE 1-4 Gas Module II, Gas Module SE, and Gas Module SE with Spirometry

Anesthetic Agent Sensor

The Anesthetic Agent Sensor is a sidestream gas analyzer, measuring real time concentrations of CO Desflurane, and Sevoflurane).

The Anesthetic Agent Sensor is a non-dispersive infrared analyzer, measuring absorption of the gas sample at seven infrared wavelengths, which are selected using optical narrow band filters. The IR lamp is a 4W filament, surrounded by thermal isolation. There is a hole in the isolation, passing the radiated light to a conical measuring chamber with a 4 mm length.

FIGURE 1-5 Anesthetic Agent Sensor Principle

From the sample chamber, radiated light goes into seven tubular light guides with reflective inner surfaces. At the other end of each light guide there is a thermopile infrared radiation detector with an optical filter in front of it.

, N2O and five anesthetic agents (Halothane, Enflurane, Isoflurane,

The Temp sensor measures the Anesthetic Agent Sensor’s temperature and uses it for temperature compensation.

1 - 6 0070-10-0522 Gas Module Service Manual Addendum

Theory Of Operation Anesthetic Agent Sensor

Anesthetic agents or mixtures of two anesthetic agents are automatically identified and concentrations of the identified agents are measured. The Anesthetic Agent Sensor also detects mixtures of more than two agents.

FIGURE 1-6 Infrared Absorbance of N

O and CO

Concentrations of CO2 and N2O are calculated from the absorption measured at 3 to 5 m.

FIGURE 1-7 Infrared Absorbance of Anesthetic Agents

Identification of anesthetic agents and calculation of their concentrations is performed by measuring absorptions at five wavelengths in the 8 to 9 m band and solving for the concentrations from a set of five equations.

The measuring accuracy is achieved utilizing numerous software compensations. The compensation parameters are determined individually for each Anesthetic Agent Sensor during factory calibration.

Gas Module Service Manual Addendum 0070-10-0522 1 - 7

Anesthetic Agent Sensor Theory Of Operation

1.2.2 Gas Module 3

FIGURE 1-8 Gas Module 3

FIGURE 1-9 Gas Module 3 Anesthetic Agent Sensor

The Anesthetic Agent Sensor is a sidestream gas analyzer, measuring real time concentrations of CO Desflurane, and Sevoflurane).

The Anesthetic Agent Sensor is a non-dispersive infrared analyzer, measuring absorption of the gas sample at up to eight infrared wavelengths, which are selected using optical narrow band filters.

, N2O and five anesthetic agents (Halothane, Enflurane, Isoflurane,

1 - 8 0070-10-0522 Gas Module Service Manual Addendum

Theory Of Operation Anesthetic Agent Sensor

N2O

Absorbance

Wav eleng th ( )

m

3.5 4 4.5 54.5

Absorbance

Wav eleng th ( )

m

78 10

Desflurane

Isoflurane

Enflurane

Sevoflurane

Halothane

91112

m

The absorption spectra for CO2, N2O, and the five anesthetic agents Halothane, Enflurane, Isoflurane, Sevoflurane, and Desflurane are shown in FIGURE 1-10 and FIGURE 1-11.

FIGURE 1-10 Infrared Absorption Spectra for N

O and CO

FIGURE 1-11 Infrared Absorption Spectra for Anesthetic Agents

To identify seven different gases in a mixture, measurements are done at seven different wavelengths. Measurements are done at an eighth wavelength for reference. The AION Multigas Analyzer uses the absorption peaks at 4.2 and 3.9 for measuring CO N

O respectively and the absorption peaks in the 8–12 range for measuring anesthetic

agents. See FIGURE 1-10 and FIGURE 1-11.

and

A set of narrow optical band pass filters intercepts a broadband infrared source to provide these wavelengths. The individual filters are mounted in a rapidly rotating filter wheel that intersects the light path. The filtered light passes into a cylindrical measurement chamber. At the other end of the chamber, there is an infrared radiation detector, whose output is directed to the host interface through the signal processor. See FIGURE 1-12.

™

Gas Module Service Manual Addendum 0070-10-0522 1 - 9

Anesthetic Agent Sensor Theory Of Operation

Gas Inlet Gas Outlet

Infrared

Detector

Signal

Processor

Host

Interface

Measurement

Chamber

Light

Source

Filter Wheel &

Optical FIlters

FIGURE 1-12 Optical Path

No radiation is absorbed if the measurement chamber is empty. The output signal from the detector is at maximum amplitude at a concentration of zero. Lower amplitudes indicate the presence of gases in the measurement chamber.

To establish the zero reference, the AION

™

Multigas Analyzer occasionally switches the zero

valve to direct ambient air through the measurement chamber.

1 - 10 0070-10-0522 Gas Module Service Manual Addendum

Theory Of Operation O2 Sensor

Switched Magnetic field

Mixture out

Electromagnet

Microphone

Sample in

Reference in

1.3 O2 Sensor

1.3.1 Gas Module II, Gas Module SE, and Gas Module SE with Spirometry

FIGURE 1-13 O2 Sensor

The differential O configuration. The gas sample along with reference room air are conducted into a gap in an electromagnet with a strong magnetic field switched on and off at a frequency of approximately 165 Hz.

An alternating differential pressure is generated between the sample and reference inputs due to forces acting on the oxygen molecules in a magnetic field gradient.

The pressure is measured with a sensitive differential transducer, rectified with a synchronous detector and amplified to produce a DC voltage proportional to the O difference between the two gases to be measured.

Sensor uses the paramagnetic principle in a pneumatic bridge

concentration

FIGURE 1-14 O

Gas Module Service Manual Addendum 0070-10-0522 1 - 11

Measurement Principle

O2 Sensor Theory Of Operation

1.3.2 Gas Module 3

Oxygen measurements are essential for correct gas measurement in the AION™ Multigas Analyzer. Because oxygen does not absorb infrared light to the same extent as other breathing gases and must be measured using another method, there is no built in oxygen measurement module. The Gas Module 3 uses a Servomex Paramagnetic Oxygen Sensor.

FIGURE 1-15 Servomex Paramagnetic Oxygen Sensor

The Servomex Paramagnetic Oxygen Sensor uses the paramagnetic susceptibility of oxygen, which is physical property that distinguishes oxygen from most common gases. Inside the sensor are two nitrogen-filled glass spheres mounted on a strong rare metal taut-band suspension. The assembly is suspended in a symmetrical non-uniform magnetic field. In the presence of paramagnetic oxygen, the glass spheres are pushed further away from the strongest part of the magnetic field. The strength of the torque acting on the suspension is proportional to the oxygen concentration (see FIGURE 1-16).

Paramagnetic technology is non-depleting, which means there are no consumable parts, ensuring consistent performance over time. The selectivity of the paramagnetic measurement for oxygen means there is no interference from other respiratory gases. The small volume chamber allows a rapid gas exchange, giving the capability for fast response oxygen measurement.

1 - 12 0070-10-0522 Gas Module Service Manual Addendum

Theory Of Operation O2 Sensor

Permanent

Magnets

Feedback

Signal

Light Source

Photo Detector

Current proportional

to O

concentration

Output Voltage proportional

to O

concentration

FIGURE 1-16 The Paramagnetic Oxygen Sensor Measurement Principle

Gas Module Service Manual Addendum 0070-10-0522 1 - 13

CPU Board Theory Of Operation

Signal Processing

CPU Board

TPX Board

PVX Board

Flow Press

OM Board

MUX

CPU

80C196NT

Anaes.

Agents

N2O CO

IR Thermopile Sensors

T Sensor

2 ch A / D 16 bit

Module Bus

MUX

and

buffer

x 5

x 2

RS-485

driver

MUX

and

buffer

preamps

T Sensor

Signal Processing

Control Logic

CPU Board

Lamp Unit

OM Board

PVX Board

PVX valves

MUX

Valves

A / D

Module Bus

TPX Lamp

Gas press

Diff press

MUX &

buffer

Valves

CPU

80C196NT

Fan

pneumatics unit

reset

data

Lamp Current Sensing

A / D

Temp

sensor

Control Logic

1.4 CPU Board

1.4.1 Gas Module II, Gas Module SE, and Gas Module SE with Spirometry

The CPU board contains the processor, memory and A/D converters that are common to the whole module. The CPU board also contains preamplifiers for the Anesthetic Agent Sensor and the drivers for the valves, fan and pump. The module is connected to the module bus through a RS-485 serial channel.

FIGURE 1-17 CPU Signal Processing

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FIGURE 1-18 CPU Control Logic

Theory Of Operation CPU Board

1.4.2 Gas Module 3

1.4.2.1 PCB

Power is a dedicated routing from the 12 V power filter. Power ground and signal ground are connected on this board. The screws that attach the board to the enclosure are also connected to chassis ground.

1.4.2.2 Power

To reduce noise from the power supply, both the 5 V and 12 V power lines are filtered. A 5 V to 3.3 V linear regulator supplies power to the microcontroller. If the 5 V power supply drops below 4.3 V, a reset signal is sent to the microprocessor.

1.4.2.3 Microcontroller

The microcontroller supports the following communication ports:

•AION

•Spirometry

• Patient Monitor

•Service

All ports use the RS-232 communication protocol. A real time clock (RTC) powered by either

3.3 V or by battery enables logging of malfunctions. If the RTC fails due to battery depletion

during battery mode, functionality is not affected.

™

1.4.2.4 Battery

The battery that supports the RTC in the microcontroller has a minimum lifetime of 7 years. When the device is running on AC power, there is zero drain on the battery, thus prolonging its lifetime.

Immediately after installing a new battery, the device should be power cycled to avoid high battery currents (~540 µA). Follow the battery supplier’s handling recommendations.

The battery is installed at component number B401 on the PCB. The battery positive node is marked with a “+” on the PCB and has two holes to differentiate it from the negative node which has one hole on the PCB.

1.4.2.5 SPI Memory

The 8 Mb capacity of the SPI memory can store an error log with timestamps to facilitate debugging and service.

Gas Module Service Manual Addendum 0070-10-0522 1 - 15

O2 Board Theory Of Operation

Calibration Data Stored in

EEPROM

CPU Board

TPX Board

PVX Board

OM Board

Module Bus

RS-485

driver

CPU

80C196NT

EEPROM

OM Board

Factory calibration data for PVX

Factory calibration data for OM and TPX

EEPROM

Correction data for amplification and offset of all amplification channels

EEPROM

Calibration Data Stored in EEPROM

1.5 O2 Board

The O2 board is only used in the Gas Module II, Gas Module SE, and Gas Module SE with Spirometry.

The O2 board contains the specific electronics for the O2 sensor. Sample flow measurement and sampling system pressure sensors are on this board. It also contains EEPROM’s that store factory calibration data of both the Anesthetic Agent and O

sensors.

FIGURE 1-19 O

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Board Calibration Data Stored in EEPROM

Theory Of Operation Communication Interface Board

1.6 Communication Interface Board

1.6.1 Gas Module II, Gas Module SE, and Gas Module SE with Spirometry

This board is a converter between the Patient Monitor and the Gas Module. It converts the proprietary RS-232 hardware protocol to the Gas Module’s RS-485 hardware protocol and vice versa. The board contains a programmable micro-processor (Intel 87C196KD), a QUART (Exar82C684CJ) and line drivers for RS-232 and RS-485 communication lines. For production test purposes the RS-485 lines have been connected to D-connector X2 pins 1,5,6 and 8. Refer to the figure below.

FIGURE 1-20 Connectors Pin Configurations

Gas Module Service Manual Addendum 0070-10-0522 1 - 17

Communication Interface Board Theory Of Operation

1.6.2 Gas Module 3

1.6.2.1 Patient Monitor

The interface to the patient monitor is a D-sub, 25-pin, female connector that uses the RS-232 communication protocol.

1.6.2.2 AION

™

The interface to the AION™ is a 2 x 17-pin IDC with locking clips. Communication between the HOST and the AION distributed from the communication board to the AION

™

is with the RS-232 communication protocol. 12 V power is

1.6.2.3 Servomex

The interface to the Servomex is a 2 x 8-pin IDC with locking clips. All communication is to the AION

™

through the communication board.

1.6.2.4 DRYLINE™ Receptacle

The interface to the DRYLINE™ receptacle is a 4-pin picoblade. All communication is to the

™

AION

through the communication board.

1.6.2.5 OXIMA Receptacle

The interface to the OXIMA receptacle is a 10-pin DF20 from Hirose. All communication is to the AION

™

through the communication board.

1.6.2.6 LED

Power ON indication is a green LED. Flash programming mode is indicated with a green LED close to the flash programming switch for the AION

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1.6.2.7 Switches

• SW201 is the flash programming initialization button for the AION

• SW202 is for future use

• SW501 is a reset switch for the microprocessor

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