Fisher MR730, MR720, MR700, MR480 User manual

5 (1)

TECHNICAL MANUAL

RESPIRATORY HUMIDIFIER MODELS

MR730

MR720

MR700

MR480

Revision D

Issued 23 October 1995

Copyright © 1991 Fisher & Paykel Ltd, Healthcare Division

Auckland, New Zealand

Fisher& Paykel

HEALTHCARE

Fisher & Paykel Healthcare have a policy of continued product improvement and reserve the right to alter specifications without notice.

Fisher & Paykel

Healthcare Division.

Fisher & Paykel Electronics Limited.

P.O. Box 14348, Panmure.

Auckland, New Zealand.

Telephone: +64-9-574 0100

Facsimile: +64-9-574 0158

Part Number 185 040 646

Issued 23/10/95

Technical Manual for Respiratory Humidifier models:

MR730 Dual Servo

MR720 Dual Servo (anaesthesia)

MR700 Dual Servo

MR480 Single Servo

Changes to Technical Manual Since Last Version.

 

Description

of Change

Page Numbers

 

 

 

Affected

GENERAL

Rewrite and update to

incorporate change to Rev H PCB

various

and version

3.0 software

 

 

MR730/720/700/480 Technical Manual # Revision D * issued October 1995

 

CONTENTS

 

 

 

 

 

 

 

 

 

 

 

 

 

PAGE

1.0

MR700

Series General Specifications essence

1

1.1

Electrical

Specifications

 

 

 

 

 

 

 

 

 

 

1

1.1.1

Models

 

MR730/720/700 ..

 

 

 

 

 

 

 

 

 

1

1.12

Model

MR480

 

 

 

 

 

 

 

 

 

 

 

„I

1.1.3

Common

Electrical Specifications (All Models).

 

 

 

wel

12

Standards

and

Approvals

 

 

 

 

 

 

 

 

 

1

13

Temperature

Control

 

 

 

 

 

 

 

 

 

 

2

14

Temperature

Sensing..

 

 

 

 

 

 

 

 

 

 

πο

1.5

Temperature

Display ..

 

 

 

 

 

 

 

 

 

 

2

2.0

Operating

Controls

And

Modes

 

 

 

 

 

 

+3

2.1

Adjustable

Controls

 

 

 

 

 

 

 

 

 

 

 

…3

2.1.1

Airway

 

Temperature

Control

 

 

 

 

 

 

 

 

....3

2.1.2

Chamber

Control (Heater Wire On Mode Only).

 

 

 

3

2.2

Push Switches

 

 

 

 

 

 

 

 

 

 

 

 

 

„3

221

Mute Button

 

 

 

 

 

 

 

 

 

 

 

 

3

222

Chamber

Temp

Button..

 

 

 

 

 

 

 

 

 

3

2.2.3

Standby Button (MR700/720/730 only) ...

 

 

 

 

 

3

2.24

Heater

Wire

Switch

(MR720,

MR730

only).

 

 

 

 

4

23

Power

Up

Seguences

 

 

 

 

 

 

 

 

 

 

4

2.3.1

Version

1.0

Software

 

 

 

 

 

 

 

 

 

 

....4

2.3.2

Version 2.0 and Version 3.0 Software

 

 

 

 

 

 

4

24

Heater Wire On Mode (All models except MR480)..

 

 

 

4

2.5

MR730/720

in

Heater Wire Off

Mode

and MR480 ..

 

 

 

s.m.

2.6

Warm

Up

Mode

 

 

 

 

 

 

 

 

 

 

 

 

„5

2.6.1

MR700/MR730

and

MR720(version

1.0) in Heater Wire Mode..

 

5

2.62

MR700/MR730

and

MR720(version

1.0)

in Non

Heater Wire

Mode

and MR480...

5

2.6.3

MR720

 

With Version 2.0/3.0 Software .

 

 

 

 

 

ο

2.7

Standby Mode

 

 

 

 

 

 

 

 

 

 

 

 

 

5

2.7.1

MR700/MR730

and

MR720

(Version

1.0)

Only.

 

 

 

~ „5

2.7.2

MR720

 

Standby

Mode (Version

2.0

and

3.0

software only) .....................ci rsrerresserserersererses 5

3.0

Alarms

and

Indicators...

 

 

 

 

.

 

 

 

.6

3.1

Temperature

Probe

Alarm

 

 

 

 

 

 

 

 

 

6

3.2

Alarms In Heater Wire Mode (MR700/720/730 only)..

 

 

6

3.2.1

Heater

Wire

Alarm........

 

 

 

 

 

 

 

 

 

6

3.2.2

Airway

 

temperature

High

Alarm

 

 

 

 

 

 

 

6

3.2.3

Airway

 

temperature

Low

Alarm.

 

 

 

 

 

 

 

7

3.2.4

Chamber

Temp

High

Alarm

 

 

 

 

 

 

 

 

7

3.2.5

Chamber

Temp

Low

Alarm.

 

 

 

 

 

 

 

 

7

3.2.6

Set

Low

Waming.................

 

 

 

 

 

 

 

 

7

3.3

Temperature Alarms in Non Heater Wire Mode (includes MR480)..

 

8

3.3.1

Heater

WireAlarm.........................

 

 

 

 

 

 

8

3.3.2

Airway

 

Temperature

High

Alarm..

 

 

 

 

 

 

8

3.3.3

Airway

 

Temperature

Low

Alarm

 

 

 

 

 

 

 

.8

3.4

Audio

Alarm

 

 

 

ee

 

 

 

 

 

 

 

 

 

.8

3.5

Safety Protection (All Models)...

 

 

 

 

 

 

 

 

.8

3.5.1

Temperature

Deviations...

 

 

 

 

 

 

 

 

 

.8

3.5.2

Microprocessor

Watch Dog

 

 

 

 

 

 

 

 

…8

4.0

Circuit

Operation

 

 

 

 

 

 

 

 

 

e.

9

41

Introduction

 

 

 

 

 

 

 

 

 

 

 

 

 

 

.9

4.2

Control Board ..

 

 

 

 

 

 

 

 

 

 

 

 

.9

4.2.1

Control

Thermistors

 

 

 

 

 

 

 

 

 

 

.9

4.2.2

Input Analog Switches U8 and U9

 

 

 

 

 

 

.9

4.2.3

Analog to Digital Converter U10 b,d,e.

 

 

 

 

 

9

 

 

MR730/720/700/480

Technical

Manual

#

RevisionD

3#-

Issued October

1995

CONTENTS

424 Processor Control U3

4.2.5Power Line Interrupt (Revisions D/F PCBs).

4.2.6Power Line Interrupt (Revision H PCB)

4.2.741 °C Comparator

4.2.8Heater Plate Overtemperature..

4.2.9Watch Dog...

43 Power Board......

4.3.1Revision D/F PCBs

4.3.2Revision H PCBs.......

44 Probe Temperature versus Thermistor Resistance..

5.0

Calibration .....

coroa

ces

esses

conse

13

5.1

Introduction ...

 

 

 

 

 

13

5.2

Equipment Required.

 

 

 

13

53

Calibration Procedure for Models with Revision D PCBs or earlier

 

13

54

Calibration Procedure for Models with

Revision

F PCBs or later...

„14

6.0

Performance

Check

ee

veses

.

SS

6.1

Introduction

 

 

 

 

 

 

 

6.2

Performance

Check

MR730/720/700

 

 

 

15

6.2.1

Equipment

Required ..

 

 

 

15

6.2.2

Static Test

Sequence (MR73

00)

 

 

15

6.2.3

Dynamic

Test

Sequence (MR730/720/700

 

 

16

63

Performance

Check

(MR480)....

 

 

 

 

6.3.1Equipment Required .........

6.3.2Static Test Procedure (MR480).

6.3.3Dynamic Test Procedure (MR480).

64Dual Probe Temperature Test.

6.4.1Equipment Required ..

642 Test Procedure .... 19

7.0

Servicing

Information

a

20

71

Introduction

 

 

 

72

Printed Circuit Board Removal ..

 

 

7.2.1

Control

PCB

 

 

722

Power PCB

 

 

73

Replacement of Revision D Power & Control PCB

Assemblies...

 

74

Heater Plate

 

 

 

7.5Fault Location

7.6Screw Torque Settings.

8.0

Schematics, Part Lists and Mechanical Drawings

8.1

MR700

Series Circuit Layout

 

Block

Diagram

82

Component Layout - Revision H PCB

 

83

Component

Layout

- Revision

F

PCB..

 

84

Component

Layout

- Revision

D

PCB .....

 

8.5

Link Pad Locations for Programming

Control Options - Revision H PCB

8.6

Circuit

Diagrams

- Revision

H

PCB

Control

PCB.

 

Circuit

Diagrams

- Revision

H

PCB.Power

PCB ...

8.7Circuit Diagrams - Revision F PCB Control PCB..

Circuit Diagrams - Revision F PCB Power PCB.

8.8Circuit Diagrams - Revision D PCB Control PCB .

Circuit Diagrams - Revision D PCB Power PCB

8.9Electrical Partslist................. esere

8.9.1Contro! Board Components: (Revision H PCB)

8.9.2Power Board Components: (Revision H PCB)...

MR730/720/700/480 Technical Manual # Revision D * Issued October 1995

CONTENTS

PAGE

8.10Mechanical Parts List ....

8.10.1MR480 Mechanical Parts

8.10.2MR730/720/700 Mechanical Parts.

8.10.3Heater plate Assembly Parts (MR730/720/700/480) .

8.11Exploded Diagrams: MR480..............

8.11Exploded Diagrams: MR730/720/700

8.12Exploded Diagrams:Heater plate Assembly MR730/720/700/480 (Inverted View

8.13PCB Identification Diagram .......................

8.14 Power PCB Harness Connection Diagram .

9.0

Product Change History.....

cerros

eres

55

9.1

Compatibility of Software and Hardware Versions..

 

 

9.2

Model

Number

Explanation .

 

 

 

93

Serial

Number

Explanation ..

 

 

 

Appendix A.

 

 

conos

 

 

00000

 

Al

Calibration Mode... sine

an

A2

Engineering

Menu

 

 

eeeeeeeen eee rn

 

A2.1

Engineering display functions: Heater Wire Mode.

 

A22

Engineering Functions: Non Heater Wire Mode ....

 

A2.3

Integral

Display

 

 

 

 

A3

Programming

Control

Options .

 

 

 

A4

Glossary

of

Abbreviations

 

 

 

A5

Error Codes

 

 

 

 

 

 

A6

MR700 Series

Humidifier Serial

Data

Interface

 

A6.1

Serial

Data

Format

 

 

rire

 

A6.2

Status

Information.

 

 

 

 

A6.3

Remote

Standby ....

 

 

 

46.4

Serial

Data

Interface Connector.

 

.

A7

Revision

F

&

H PCB

Schematic

Diagrams

nn

Appendix

B

veve

 

 

 

 

 

BI

Recommended

Maintenance

Schedule...................

 

B2

Recommended

Maintenance

Schedule

Checklist...

....63

Appendix

C....

 

κο.

sous

ce

.6S

C1

Troubleshooting Guide For

The

MR700

Series Respiratory Humidifiers.

 

C2

MR700

Series

Fault Flow Chart

For No

Go Condition

 

MR730/720/700/480 Technical Manual # Revision D # issued October 1995

MR730/720/700/480 Technical Manual. # RevisionD 3 Issued October 1995

page 1

1.0MR700 SERIES GENERAL SPECIFICATIONS

This documentation defines the technical specifications of the MR730, MR720, MR700 and MR480 respiratory humidifiers.

The MR730/720 models are Heated Wire humidifiers with the option of disabling the Heater Wire. The MR720 has a lower alarm limit and an extended warmup mode for use in Anaesthesia.

The MR700 model is exclusively a Heated Wire humidifier.

The MR480 model is a non Heated Wire humidifier.

1.1ELECTRICAL SPECIFICATIONS

1.1.1MoDELs MR730/720/700

Suppiy

Voltage:

230V

+25V

 

 

 

-

127V

x

12V

 

 

 

 

115V

 

 

 

 

 

 

100V

+

10V

 

 

Supply

Frequency:

50

-

60

Hz

 

 

Supply

Current:

1.0

A

maximum

at

230V

 

 

1.9

A

maximum

at

127V

 

 

2.0

A

maximum

at

115V

 

 

2.4

A

maximum

at

100V

Heater

Wire Capacity:

60

W

 

 

 

 

1.1.2MobeL MR480

Supply

Voltage:

230V

+25V

 

 

 

 

115V

 

 

 

 

 

100V

+10V

 

 

Supply

Frequency:

50

-

60 Hz

 

 

Supply

Current:

0.7

A

maximum

at

230V

 

 

1.4

À

maximum

at

115V

1.6À maximum at 100V

1.1.3COMMON ELECTRICAL SPECIFICATIONS (ALL MODELS)

Heater

Plate

Power:

150 W

Heater

Plate

Overheat Protector:

Operates at 118 °C + 6 °C

1.2STANDARDS AND APPROVALS

Classification under

UL544,

CSA-C22.2 No.125

 

 

JEC601-1,

AS3200.1,

BS5724:Part 1, DIN

VDE 0750 Teil 1

 

Class

1

 

 

 

 

 

Type

B

 

 

 

 

 

Drip

Proof

 

 

 

 

Continuous

Operation

 

 

 

Not to be

used in the

presence of flammable

anaesthetics.

MR730/720/700/480 Technical Manual # Revision D * issued October 1995

page 2

1.3TEMPERATURE CONTROL

PID (Proportional Integral Derivative) control of Heater Wire (in Heated Wire mode operation only) and heater plate.

1.4TEMPERATURE SENSING

Temperature measurement using standard characteristic thermistors (YSI 400 compatible) mounted in

fast response temperature

probes, located at the patient end of the delivery tube and at the humidifying

chamber outlet.

 

1.5TEMPERATURE DISPLAY

Three

digit

14mm

7 segment LED (Light Emitting Diode) display.

Range

5.0

to

80.0

degrees. Below 5.0 degrees displays 'Lo'. Above 80.0 degrees displays 'Hî'.

Accuracy

25.0 to

45.0 degrees + 0.3 degree.

MR720/720/700/480 Technical Manual # Revision D % Issued October 1995

page 3

2.0 OPERATING CONTROLS AND MODES

2.1ADJUSTABLE CONTROLS

2.1.1AIRWAY TEMPERATURE CONTROL

Selects the airway controlling temperature.

The

range

of adjustment

is from

29 to

40

°C

over a linear

scale

marked in

degrees

on

the

front

panel.

 

 

 

 

 

 

 

 

 

 

 

The

temperature

can be

set

with

a resolution

of

0.1

°C.

The

set

temperature

is flashed

on

the display

when

the control

knob

is rotated and

continues

to be

flashed

for

five

seconds

after

the

last adjustment.

2.1.2

CHAMBER

CONTROL

(HEATER

WIRE

ON

 

MODE

ONLY)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The

temperature of

the gas

leaving

the

chamber

is

regulated

by

the

Chamber

Control

knob,

it sets

the

 

 

difference between the chamber outlet

temperature

and

the

airway

temperature delivered

to

the patient.

 

The

setting

of the

Chamber

Control, when

added

to

the

setting

of

the

Temperature Control,

determines

 

the

chamber

outlet

set

temperature.

This

Chamber

Control

has

a linear

range

of

adjustment

from

-5

to

 

+2 °C marked in one degree steps and

can

be

set

with a

resolution

of 0.5

°C.

The

value is

flashed

on

the

 

Airway display as the control knob is

rotated

and

 

continues

to

be flashed

for

five

seconds

after the

last

 

adjustment.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Every humidifier is also supplied with

a

fixed

chamber

control

knob.

This prevents

inadvertent

 

 

 

adjustment of the chamber control by

preadjusting the existing knob to the desired setting and then

 

 

 

replacing

the

normal

knob

with

the

fixed

knob.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2.2PUSH SWITCHES

2.2.1MUTE BUTTON

A momentary push will disable an audible alarm for 3 minutes (except low temperature alarm in non

heater wire mode which is ten minutes).

A secondary function is that in conjunction with the Chamber Temp switch enables entry to the engineering menu (refer Appendix A2).

On every initial push of the mute button a momentary audio beep indicates function operation.

2.2.2CHAMBER TEMP BUTTON

For MR700

Series Humidifiers

with

Version

1.0

Software:

 

 

 

 

 

Operation of this switch causes the airway temperature display to

momentarily

blank

then show

the

chamber

outlet temperature.

A

green

LED

adjacent

to

the switch

is enabled

to

indicate that this

function

is active.

On

release

of this

switch

the

display reverts

immediately

to show

the

airway

temperature.

This button

is used in

conjunction

with the

mute

to

enter the engineering menu

(refer

Appendix

A2).

For MR700 Series Humidifiers with Version 2.0 and Version 3.0 Software:

Operation of this switch causes the airway temperature display to momentarily blank then show the

chamber

outlet

temperature. A green LED

adjacent

to the switch

is

enabled to

indicate that this

function

is active.

On release of this switch the

display continues te

show

the

chamber

outlet

temperature for 2

seconds

before

blanking momentarily

and

reverting

to show

the

airway

temperature.

 

 

This button is

used in conjunction with

the

mute to

enter the

engineering

menu

(refer

Appendix

A2).

2.2.3STANDBY BUTTON (MR700/720/730 ONLY)

This button

has to be depressed for one

second

to

enter

or

exit

the

standby

mode.

When

the

adjacent

amber

LED

starts

to flash (100/minute)

the

button

can

then

be

released

and

the Humidifier

remains in the

standby

mode.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

To exit

Standby mode press the Standby

button

for 1s,

the

amber

LED

will then

turn

off.

An audio

beep accompanies

a change in the Standby

mode

state.

 

 

 

 

 

 

 

 

 

MR730/720/700/480 Technical Manual # Revision D. 3 Issued October 1995

 

 

 

 

 

 

 

 

 

page

4

 

 

 

 

 

 

 

2.2.4

HEATER

WIRE

SwiTCH

(MR720,

MR730

ONLY)

 

 

 

 

 

 

 

 

 

This is

a latching, push

operated,

switch

which

selects

between the

heater wire

mode

and non-heater wire

 

mode.

The

adjacent green

LED,

if on,

indicates

 

that the humidifier

is

operating

in the heater wire

mode.

 

Pressing this switch will cause an

audible

beep

and the

LED changes

to indicate the

new state.

A

heater

 

wire alarm

will

commence

if switching

to

the heater wire mode with no heater

wire

connected

or

if

 

switching to the

non heater

wire

mode if a

heater

wire

is connected.

 

 

 

 

 

 

2.3POWER UP SEQUENCES

2.3.1VERSION 1.0 SOFTWARE

After switch on the humidifier goes through the following sequence. Note that each displayed information is flashed for 2 seconds.

.

Watchdog

circuit

test

If successful the 'SEE MANUAL'

LED

lights

briefly.

.

Display Test

 

All indicator

LEDs

are illuminated

and

'8.8.8.'

is

displayed on the

 

 

 

 

Airway

Temperature

display

 

 

 

 

 

Temperature Control Setting

eg '37.0'

is displayed

 

 

 

 

 

 

Chamber

Control

setting

If heater

wire

mode

is selected then the

chamber

control setting is

 

 

 

 

displayed eg

'-1.0'.

Not applicable

for

MR480

 

 

9

Software

Version

Number

1.0

 

 

 

 

 

 

 

 

Maximum

Heater

Plate Setting

eg'110'

 

 

 

 

 

 

 

9 Audio Beep

2.3.2VERSION 2.0 AND VERSION 3.0 SOFTWARE

After switch on the humidifier goes through the following sequence. Note that each information is

displayed for 2 seconds, then the display is momentarily blanked.

 

.

Watchdog

circuit

test

 

 

If

successful

the 'SEE

MANUAL'

LED

lights

briefly.

 

 

 

Display

Test

 

 

 

 

All

indicator

LEDs are

illuminated

and

'8.8.8.'

is

displayed on

 

 

 

 

 

 

 

 

 

 

the

Airway

Temperature display

 

 

 

 

 

 

 

.

Model

Number

 

 

 

eg

'730°

 

 

 

 

 

 

 

 

 

 

 

 

 

9

Software

Version

Number

 

eg

'2.0'

 

 

 

 

 

 

 

 

 

 

 

 

 

.

Temperature

Control

Setting

 

eg

'37.0'

is

displayed

 

 

 

 

 

 

 

 

 

 

9

Chamber

Control

setting

 

If

heater

wire

mode

is

selected then

the

chamber

control

setting

 

 

 

 

 

 

 

 

 

 

is

displayed eg '-1.0'.

Not applicable

for MR480

 

 

 

 

Maximum

Heater

Plate Setting

ερ

110'

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Audio

Beep

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2.4

HEATER

WIRE

ON

MODE

(ALL

MODELS

EXCEPT

MR480)

 

 

 

 

 

 

 

 

 

In the

Heater Wire On Mode (heater wire

switch

green

LED

on) the

heater

plate

and heater wire

are

 

regulated

to maintain

the

desired

temperature and

humidity,

within

close

limits

with

a minimum

of

condensation. To minimise rainout or maximise humidification, the chamber outlet temperature can be adjusted to control at a fixed offset from the set airway temperature. The front panel Chamber Control

knob is used for this purpose, see 2.1.2 above.

2.5 MR730/720 IN HEATER WIRE OFF MODE AND MR480

In the non Heater Wire mode

of the

MR730/720

(heater

wire

switch

green

LED

off)

the

delivery

 

temperature

is

maintained

by

heater

plate

control

only.

The

sensor

at

the delivery

hose

end controls the

heater

plate

to

deliver

the

selected temperature.

The sensor

at

the

chamber

outlet

is

employed in

a

backup

safety

mode,

to limit

the chamber

outlet

temperature

to

a maximum

of

66

°C.

In this way

safety

at low flow rates (below 5 L/minute) is enhanced at the sacrifice of some low flow performance.

MR730/720/700/480 Technical Manual # Revision D # Issued October 1995

page 5

2.6WARM UP MODE

The Low temperature alarm is disabled during warm up. It is enabled as soon as any of the following conditions are met:

2.6.1 MR700/MR730 AND MR720(VERSION 1.0) IN HEATER WIRE MODE

the airway temperature gets within 0.8 degrees of the temperature control setting.

 

 

the

airway

temperature

does not increase by 2

°C

 

within

4

minutes

(2 minutes for version

3.0

 

 

software)

 

 

 

 

 

 

.

 

 

 

 

e

the

airway

temperature

does not get within 2

ºC

of

the set

point within ten minutes of

switch on.

2.6.2

MR700/MR730

AND MR720(VERSION 1.0) IN NON HEATER WIRE MODE AND MR480

 

 

 

 

the

airway

temperature gets above 30 °C

 

 

 

 

 

 

 

 

 

 

the

airway

temperature does not increase by 2

°C

 

within

15

minutes

 

 

 

 

 

the

airway

temperature

increases by 2 °C within

15

minutes

but still

has not reached 30

°C

after a

further

15 minutes.

 

 

Note:- In this mode the audio alarm

is not enabled for 30

seconds after the Airway Temp Low LED

switches on.

At this time the heater

plate circuit switches

off.

And a low temperature alarm mute is for 10 minutes, during which the heater plate is enabled.

2.6.3

MR720

WITH VERSION

2.0/3.0

SOFTWARE

 

 

 

 

If the

above

warm up

conditions

are

not initially

met

the MR720

will automatically enter the standby

 

mode

for

20

minutes

for

version

2.0

software and

30

minutes for

version 3.0 software (refer 2.7).

2.7STANDBY MODE

2.7.1

MR700/MR730

AND

MR720

(VERSION 1.0)

ONLY

 

 

 

 

 

 

The

standby

mode

can be entered or exited

by

depressing the standby button for

1

second. A

beep will

 

be

emitted once

successful entered or exited

standby mode (refer

2.2.3)

 

 

 

 

In the

standby

mode

all Low

Temperature

alarms

are

inhibited,

the heater plate

is

controlled

to a

 

nominal

40.0

°C

and the heater wire is on

a

15%

duty

cycle.

 

 

 

 

 

Standby

mode

is

automatically exited after

20

minutes

(30 minutes for version 3.0 software) and the

 

warm

up

mode

is

entered (the

low temperature

alarms

remain disabled - refer section 2.6).

 

A Remote Standby request (see Appendix A6.3) enables the standby mode and turns the standby amber LED permanently on.

2.7.2 MR720 STANDBY MODE (VERSION 2.0 AND 3.0 SOFTWARE ONLY)

The

MR720

has

a

special

feature

where

it will

go

into

a

standby

mode automaticaliy after turn on

if the

warm

up

conditions are not

met.

This

standby

mode

time is

20 minutes

for version

2.0 and

30 minutes

for

version

3.0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

While

in

standby

 

mode:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

a)

If

the

airway

temperature

increases

by

2

°C

at

any

time,

the

MR720

will

exit stand by mode

and

enter warm up mode. The

unit then rechecks

warm-up

exiting conditions

 

and

if these are not

met,

then

the unit re-enters

 

Standby

mode.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

b)

If

the

airway

 

temperature

has

not increased

by

2

°C

or

come

within

2

°C

of the

set temperature by

completion

of the

standby

period,

initial

warm-up

resumes.

The

unit then

rechecks

warm-up

exiting

conditions and if these are not met, the unit alarms.

MR730/720/700/480 Technical Manual # Revision D # Issued October 1995

page 6

3.0

ALARMS

AND

INDICATORS

 

 

 

 

 

 

 

 

 

 

 

 

 

3.1

TEMPERATURE

PROBE

ALARM

 

 

 

 

 

 

 

 

 

 

 

 

 

 

If the

airway

temperature

probe is disconnected

or

develops

a

low

or

high

resistance the

Temperature

 

Probe

alarm

will

be

enabled.

Indication

 

is by

a'-

-

-' message

 

on the

airway

temperature

display

plus a

 

flashing Temperature Probe red LED

and

an

audio

alarm.

 

 

 

 

 

 

 

 

Five specific fault types can be diagnosed and

are

displayed

by

the

sequence of ‘decimal

points’

in the

 

display, as shown

below:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(a)

--- .

Temperature

Probe

not

plugged

in.

 

 

 

 

 

 

 

 

 

 

 

Low

temperature (~0

°C)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Open

circuit

chamber

outlet

probe

 

 

 

 

 

 

 

 

 

 

 

Open

circuit

in common

lead

in

probe cable.

 

 

 

 

 

 

(b)---, Open circuit patient airway probe

Very low temperature (~0 °C)

(©)--.- Short circuit chamber outlet probe

Very high temperature (~100 °C)

(d)

 

- -.-.

Short circuit patient airway probe

 

 

 

 

 

 

 

 

 

 

 

 

 

Very high temperature (~100 °C)

 

 

 

 

 

 

 

 

 

(e)

 

-.-

-

Short

in

probe

cable

between

patient airway

probe

and chamber

outlet

probe

The

faults (a

to

d) above

are

checked

for at a rate of

about twice

per

second.

The

final

fault

(e) which

does

not

immediately

cause

any

apparent operating

anomaly

is

checked twice

a minute.

 

 

A Temperature

Probe Alarm immediately shuts down both heater wire and heater plate.

 

 

Once

the

alarm

condition

has been removed the

humidifier will

enter

warm

up

mode (refer

section 2.6).

3.2 ALARMS IN HEATER WiRE Mope (MR700/720/730 onLy)

3.2.1HEATER WIRE ALARM

If the

heater

wire is

disconnected or there is

a fault with the heater

wire circuit, then the Heater Wire

alarm

LED

will

start flashing and the audio

alarm wili

be enabled.

Both heater

wire and heater

plate

~ circuits will

be

shutdown.

The display will

continue to

indicate the

temperature

sensor reading

(unless

the heater wire

fuse

is open

circuit).

 

 

 

 

 

An open circuit heater wire fuse is indicated by ‘F-2' appearing on the Airway Temperature display.

On MR720/730 if the Heater Wire is connected but switched off, the alarm will sound (refer section 2.9.4).

Note:

If 'F-2' is displayed and the F2 fuse is intact then check the calibration of the 41°C overheat (refer section 5).

3.2.2AIRWAY TEMPERATURE HIGH ALARM

The red Airway Temp High LED will flash and an audible alarm will sound if the gas temperature being

delivered to the patient is 2°C

higher than the Temperature Control setting. A high temperature alarm

instantly disables both heater

circuits.

MR720/720/700/480 Technical Manual № Revision D ἃξ Issued October 1995

page 7

3.2.3AIRWAY TEMPERATURE LOW ALARM

The red Airway Temp Low LED will flash and an audible alarm will sound if the gas temperature being delivered to the patient is 2°C lower (4°C for MR720 model) than the Temperature Control setting.

Notes:

 

 

 

 

 

 

 

 

 

 

 

If Airway Temperature Low alarm

condition

persists for more

than

100

seconds

the

heater

plate

and

heater wire circuits will switch

off.

Pressing

the mute

button

will silence the Audio

alarm

and

resume

heat for a further 100 seconds,

the

Airway Temperature

Low

LED

will

continue

to

flash..

 

 

This alarm is disabled during warm-up, see section 2.6.1.

3.2.4CHAMBER TEMP HIGH ALARM

This alarm will activate if:

1) The temperature of gas leaving the humidification chamber outlet is more than 4 °C higher than the

chamber set temperature for more than 20 minutes. (The chamber set temperature is the sum of the Temperature Control setting and the Chamber Control setting).

2)The temperature of the gas leaving the humidification chamber outlet exceeds the chamber set temperature by 10 °C or more.

This

alarm causes

the heater circuits to

switch off and the Chamber

Temp

High

amber LED indicator to

start

flashing. The

audio alarm (which

can be muted) is also enabled.

This

alarm

remains active until

the high temperature condition is cleared.

3.2.5CHAMBER Temp Low ALARM

This alarm will activate if:

For Chamber Set Temperature < 35°C

The

temperature

of

gas leaving

the humidification chamber outlet is less than 4°C lower than the

chamber

set

temperature

for more

than

20

minutes.

 

 

 

 

 

 

 

OR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

For

Chamber

Set

Temperature

> 35°C

 

 

 

 

 

 

 

 

 

The temperature of gas leaving

the

humidification

chamber

outlet is less

than

31°C

for more

than 20

minutes.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

THEN:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The Chamber Temp Low alarm

amber

LED

will begin

to flash and the audio

alarm

(which

can be

muted) is

enabled.

This

alarm

remains

active until

the

low

temperature

condition is

cleared.

Pushing the

mute

button

will

silence

the Audio

alarm.

 

 

 

 

 

 

 

 

3.2.6SET LOW WARNING

Version 1.0 and Version 2.0 Software

This alarm will activate if the chamber set temperature is below 31.0 °C. In this case the Set Low amber

LED will immediately be enabled and remain on, until such time as the chamber set temperature is adjusted above 31.0 °C. There is no audible alarm.

Version 3.0 Software

This alarm will activate if either the chamber set temperature or Temperature control setting is below

34.0°C.

In these cases the Set Low amber LED will immediately be enabled and remain on, until such time as the set airway or chamber temperature is adjusted above 34.0 °C. There is no audible alarm.

MR730/720/700/480 Technical Manual # RevisionD # Issued October 1995

page 8

3.3 TEMPERATURE ALARMS IN NON HEATER WIRE MODE (INCLUDES MR480)

3.3.1HEATER WIRE ALARM

This indicates

that a heater

wire has been connected

when

the non

heater wire

mode has

been selected

(Heater

Wire

On LED

is off).

In this case the Heater

Wire

alarm

LED will be

flashing,

the audio alarm

begins

and the

heater

plate

is

switched off.

 

 

 

 

 

3.3.2AIRWAY TEMPERATURE HIGH ALARM

The red Airway

Temp

High LED

will flash and

an

audible alarm will

sound if the

gas

temperature being

delivered to the

patient

is 41°C or

higher. Power

to

the heater plate is

immediately

shut

off.

3.3.3AIRWAY TEMPERATURE LOW ALARM

The red Airway Temp Low LED will flash and an audible alarm will sound if the gas temperature being delivered to the patient is 29.5 °C or less.

Notes:

 

 

 

 

 

 

 

 

 

The

audio

alarm

is not enabled for 30

seconds

after the low temperature

LED

begins flashing.

Pushing the mute

button

disables

the

audio

alarm and restores power to

the

heater plate for ten minutes,

the

Airway

Temp

Low

LED will

continue

to

flash.

 

 

This alarm is disabled during warm-up, see section 2.6.2.

3.4AUDIO ALARM

A choice of

the ISO draft standard

audio alarm or a gliding tone can be selected by the programming

control link

(L1), refer Appendix

A3.

A momentary depression of the mute button will silence the audio alarm for about 3 minutes (except for a low temperature alarm in no heater wire mode, see 3.3.3. The relevant LED indicators remain flashing

until the alarm condition clears. Any new alarm condition occurring within a mute delay will cause the audio alarm to be re-enabled.

3.5SAFETY PROTECTION (ALL MODELS)

3.5.1TEMPERATURE DEVIATIONS

‘An

over

temperature

alarm condition

causes

an immediate shut down of both

heater

circuits. In the

case

of

a Low

Temperature

alarm, pressing

Mute

causes heating to recommence,

the Low

Temperature

LED

however remains on until the fault has cleared.

There are two independent backup over temperature protection circuits.

Firstly, an over temperature protection circuit independent of the microprocessor control continuously

monitors

the

airway

thermistor sensor.

This

backup

protection

is

preset

to

disconnect

the

heating

circuits

at 41.0 degrees.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Secondly,

a

bimetallic

thermostat

fixed to the heater plate

operates

if the

heater plate

temperature

 

exceeds

118

°C + 6

°C

and opens

the

mains

active

supply.

On

cooling,

this

protector

can

only be

reset

by gaining access to the under surface of the heater plate and manually depressing the red reset button.

Heater plate temperature is limited to 110 °C max during normal operation (80 °C for MR720). Optional heater plate limits of 50, 80 and 90 °C can be selected. (Refer Appendix A3.)

3.5.2 MICROPROCESSOR WATCH DOG

A control loop in the operating software continuously monitors for correct operation. Should a fault be detected a hardware reset circuit attempts to re-initialise the microprocessor. If this is not successful

additional hardware disables the heating circuit, blanks the display and turns the Humidifier Fault red LED on.

The watch dog circuit is tested at turn on by deliberately halting the processor and forcing initialisation.

AP YAN/ZONTZNNIAQN Tarbhnireol Manuel + Ravician MD SE ее Nrtahar 10905

page 9

4.0CIRCUIT OPERATION

41

INTRODUCTION

 

This section

describes briefly the operation of each of the circuit sections. Refer to the circuit diagrams

 

in Sections

8.6 to 8.8.

4.2CONTROL BOARD

The one basic control board, with various discreet hardware changes, provides the controlling functions for the MR730/720/700/480 range of humidifiers. Each model however is controlled by a unique software version.

4.21CONTROL THERMISTORS

Three

standard characteristic

thermistors control all temperature functions. Two thermistors

are used in a

dual

temperature

probe sensor,

another

thermistor

monitors the heater

plate temperature.

 

1. . A thermistor

is mounted

in

a probe

at

the end

of the

delivery

hose

to

measure

delivered

airway

temperature

(connector

J4-1,3). This

temperature is

indicated

by

the

digital

display on

the

humidifier front panel.

2.A second thermistor mounted in a probe measures the chamber temperature at the top of the

 

 

humidifying

 

chamber

(connector

J4-2,3).

In

heater wire mode

this

thermistor

is used to

monitor

and

 

 

control

the

chamber

outlet temperature.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.

A

third

thermistor

is permanently

mounted

in

intimate

contact

with

the heater

plate (HP)

(connector

 

 

J3-1,3). This

prevents excessive heater

plate

temperatures

during

a warm up cycle.

 

 

 

4.2.2

INPUT

ANALOG

 

SWITCHES

U8

AND

US

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The

1

by

8

analog

switch

(U8)

selects under processor control (PB0-3)

various

input signals

and

 

 

 

reference

potentials.

Selected

sequentially are potentials giving; (0-3):

the position

of

the temperature

set

 

potentiometer

VR3,

and

offset

potentiometer

VR2.

(4-6): calibration temperatures

of

9, 34.5

and

60

°C

 

across resistors R18, R17 and

R16,

and

from

(7):

the

heater

plate (HP)

thermistor.

 

 

 

 

 

 

From

 

the

3

by

2

analog

switch

(U9) under processor control (PB4-6) the airway

temperature

and

the

 

 

chamber

outlet

 

temperatures

from

the

dual

probe

temperature

sensor

are also

read.

 

 

 

 

4.2.3 ANALOG TO DIGITAL CONVERTER U10 B,D,E

The temperature probe inputs are filtered by the C30, C31, R28, R26, C19, C20 network for EMI

 

suppression.

 

The

selected

 

output

of the analog switch network U8, U9

is

fed

to

pin

10 of U10d, a

low

pass operational amplifier with a

gain

of

11.

This

stage

is filtered with

C23

to give protection from any

voltage transients appearing at its

input.

The

integrating

stage

U10b

rests

for most

of the time (50-60ms)

with R35 connected (through an

analog

switch in U9) across the

integrating

capacitor C22 holding it ina

discharged

state.

With VR5

and

R34

connected to the non-inverting

input

of U10b

the stage

has a

‘static’

gain

of about

0.5 giving a

resting

level of about -2.5 to

-3 volts

at the

output

pin

1.

 

 

 

Under processor control (PB6) when the switch section

of U9 across C22 is

opened the output of U10b

ramps up (0.1-5ms).

This

rising

ramp voltage is fed via

R36

to

the comparator

stage U10e where it is

referenced

via

R41

to

the

output

voltage

level

of

U10d.

When the ramp voltage exceeds the threshold

level

of UI0d

the

output

of

the comparator stage

U10e

switches

high.

 

This

fast

rising edge,

assisted by

the speed up capacitor C24, is fed to the RST 6.5 interrupt input of U3.

4.2.4PROCESSOR CONTROL U3

After selecting one

of the

10

input signals

through

the

switch network of U8, U9 there is a 50-60ms

 

pause to allow U10d to settle.

At

this

point

the

switch

across the integrator U10b is

opened

initiating

a

linear ramp

output

and the

14

bit

counter

in

U4

is

started.

Within a time period of 100ns to Sms the

ramp

will cause

a RST6.5

interrupt

to

occur.

The

processor

on

responding to the interrupt,

first

stops

 

MR730/720/700/480 Technical Manual № Revision D. # issued October 1995

 

 

 

 

 

page

10

 

 

 

 

 

 

 

 

 

 

the counter, then closes the

switch across the integrator readying

it

for the

next

cycle.

The

input

switch

network U8, U9 can now be

stepped

to

the

next

input.

The

14 bit

counter

can

now

be

read

and

its value

equated to the input signal.

In

this way

all

10 input channels

are

continuously

scanned.

VRS is

set

during calibration to give the

desired

ramp

rate.

Thus

all points

are scanned once

every 500-600ms, self

calibration performed, and the digital display updated.

4.2.5 POWER LINE INTERRUPT (REVISIONS D/F PCBs)

A sample of the power supply frequency is derived from the power transformer 22Vac secondary via

R56 and

O1, buffered by Schmitt trigger

USf and fed

to

the RST7.5

interrupt

of U3. The

operating

software

determines the supply

frequency

facilitating

the

generation

of

a real

time clock

and also

enabling

a zero crossing detector for triac

switching.

The ADC is also

phase

synchronised with the line

frequency

thus eliminating any

common

error from this

source.

 

 

 

 

4.2.6

Power

LINE INTERRUPT

(REVISION

H

PCB)

 

 

 

 

 

 

 

The zero

crossing

is

derived

from

the

10Vac secondary. Resistor

R61.ensures that the secondary is

 

ground referenced

when

the

diodes

D13

- D16 are not

conducting.

Network

Ri,

R69, and

C2

removes

 

any unwanted noise from the zero crossing circuit. The operating software determines the supply

 

frequency facilitating the generation of

a real time clock and also

enabling a

zero

crossing

detector for

 

triac switching.

The

ADC is

also phase

synchronised

with the line

frequency

thus

eliminating

any

 

common

error

from

this

source.

 

 

 

 

 

 

 

 

 

4.2.741 °C COMPARATOR

Operational

amplifier

U10c

is

a protection

circuit

to sense

excessive delivery

temperature

rise.

The

non

inverting

input

pin

5

is

connected directly (via connector

J4-1) to the patient

airway

thermistor.

The

 

inverting

input

goes to an adjustable divider network R32,

VR4,

R33.

VRA

is

set

during

calibration

to

ensure

that

the

output

pin

7

of

U10c

is

low

above

an input

temperature

of 41

°C.

This low

output

 

(OVHT)

is

fed

via the isolating diode resistor networks D19, R55

and

D20,

R61 to clamp the bases of

switching

transistors

Q10

and

Q12.

In

this

way,

a patient

airway

temperature

greater

than

41°C

causes

both heaters

to

be

shut

down.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A watch

dog failure,

which

is

a high

output

from

USg,

is

communicated via

isolating

diode

D11

and

 

resistor

R31

to

the inverting input of U10c.

This

also

ensures that both

heater

control

circuits are

 

clamped

off

in

the

event

of

a processor

crash.

 

 

 

 

 

 

 

 

 

 

 

 

 

4.2.8HEATER PLATE OVERTEMPERATURE

Thermistor HP senses the heater plate temperature.

Should

the

heater plate exceed the maximum heater

plate limit (default 110 °C) during normal operation,

power

to

the heater plate is discontinued until it

cools below

this

limiting

temperature.

Under

certain

operating conditions, for increased safety, lower

maximum

heater

plate temperatures

can

be selected.

 

(See Appendix

A3:

Programming

Control

Options.)

Also mounted

on

the heater plate is a mechanical

118

°C cut out which will give protection should the

electronic

control

system

fail. This

mechanical

cut

out is connected

in

series with the

power

transformer

primary and

thus

causes

complete

shut

down

of

the

humidifier should

a

serious

fault develop.

The

mechanical

 

cut

out must

be manually

reset by

means

 

of the reset button

located

on the

underside

of the

heater plate

module.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4.2.9WATCH DOG

During

operation

the

processor

is

continually

monitored

for

correct

function.

 

This

is done

by

changing

the

state

of

output

port

PB7

of

U4

 

every

16.6

or

20ms (power

line frequency

interrupt).

This

square

 

wave,

buffered

by

USb,

is fed

to

the

charge

pump

circuitry

C16,

D4,

DS

and

C15

which

ensures

that

pin

13

of USg

is

held

hard

up.

Should

this

square

wave

be interrupted for any reason,

C15 will

discharge

through R3 giving a high output

from

pin

12,

which

drives

the trap interrupt input

of U3.

This

high

trap

input forces re-initialisation of the processor which

 

may

or

may

not

be

successful

depending

on

the

 

nature

of

the

fault.

The

purpose

of

this

is

to

ensure

 

that

if

the

processor

should

fail, and

is

unable to

re-

initialise,

it

fails

in a

safe mode.

The

watch

dog

circuit

is

tested

every time the

humidifier

is

tumed

on by

deliberately

halting

program

execution

and

waiting

for initialisation via the watch

dog.

To

indicate

that

the

processor

has

failed

the

high

output

of

U5g

also

turns

on

Q3

which

lights

the 'see manual’

LED10

and

also

tums

off

the display I.C.

U7

to

blank

the

digital

display.

 

 

 

 

 

 

 

 

 

 

 

MR 720/77 9°0I7NN/ARD Tarhnicat Mania! d Ravicinn ND SE ἱσοιιωρ Octnher 4005

page 11

43 POWER BOARD

4.3.1 Revision D/F PCBs

A bridge

rectifier

(D13-D16)

supplies power to the 5

volt

regulator

Q7

mounted on

the heat

sink. This

circuit is

protected

by a 1 Amp

fuse

(Fi) mounted on

the

circuit

board.

The 5 volt

negative

supply

stabilized

by Q8,

is derived from the

voltage doubling

network

D17,

D18.

 

 

The Heater Wire (HHC) is controlled by triac Q9 which is mounted on the heat sink. Q9 is switched by

the optoisolator

U11

which

in

turn

is

driven

by

Q10.

O10

is controlled

directly

from

an

output

port of

UA on the control board.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The

resistor R52

connected

to

the

anode

of

Q9

provides a

signal

through

(HHS)

 

to USd

and

U4.

This

signal, with processor interpretation, provides

the

information

to

determine

if the

Heater

Wire is

 

connected or open circuit and also the

integrity

of

fuse

F2,

the

4

Amp fuse

supplying

power

to

the

Heater

Wire.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Тнас

ОП

(mounted

on the

heatsink)

is

controlled

by

optoisolator U12,

which

in

turn

is

controlled

by

Q12,

and

HPC.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Transistors Q5 and Q6 are a RS232 level driver for the serial data interface.

4.3.2

REVISION

H

PCBS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A bridge rectifier (D13-D16) supplies power

to the 5 volt regulator Q7

mounted

on

the

heat

sink.

This

 

circuit is protected by a

1 Amp

fuse (F1) mounted

on

the

circuit

board.

The

5

volt negative

supply

 

 

stabilized by

O8,

is derived from the voltage

doubling

network

D17,

D18.

 

 

 

 

 

 

 

 

 

 

The

Heater

 

Wire

(HHC)

is controlled

by triac

Q9

which

is

mounted

on

the

heat

 

sink.

O9

is

switched

by

 

the

optoisolator,

U11, which in

turn is

driven

by Q10.

Q10

is

controlled directly

from

an

output

port

of

 

U4

on the

control

board

(HHC).

Resistor R9,

C6

form

a

snubber

on

the

triac.

Capacitors

C8, C32

 

balance the heater wire with respect to ground.

Heater

wire

sensing

is

accomplished

through

the

optoisolator

U13

and

associated

components R51,

R52,

D21,

R66

and

R67.

 

R51

and R52

limit

the current through the LED

when

the triac is

on

or off.

With

the

triac

off

and

a

heater

wire

connected

then

the

optoisolator

will

remain

off.

Otherwise

if a

heater

wire

 

is

not connected then the optoisolator will

be

turned on

and

off in synchronisation

with

the

secondary

 

 

cycle.

 

The

output

of

the optoisolator feeds U4 on the control

board.

This

signal,

with

processor

 

 

 

interpretation,

provides

the

information

to

determine

if the Heater

Wire

is

connected or open circuit and

also the integrity of fuse F2,

the

4

Amp

fuse

supplying power

to the

Heater

Wire.

 

 

 

 

 

 

Q11

controls

power

to

the

heater

 

plate

and is under control of optoisolator

U12 and transistor Q12 via

an

output

port

(HPC)

on

U4

on

the

control

board.

Resistors

R64,

R57

 

limit the gate

current

to the

triac

and

with C33 form a snubber for the triac and the optoisolator.

Transistors Q5 and Q6 are a RS232 level driver for the serial data interface.

MR730/720/700/480 Technical Manual

RevisionD # Issued October 1995

 

 

page

12

 

44

PROBE TEMPERATURE VERSUS THERMISTOR RESISTANCE

 

 

TEMP

RESISTANCE

TEMP

RESISTANCE

 

CO

(Ohms)

CC)

(Ohms)

 

0

7352.8

36

14113

 

9

4702.2

37

1355.0

 

28

1976.6

38

1301.0

 

29

1893.3

39

1249.2

 

30

1814.4

40

1199.6

 

31

1739.2

41

1152.3

 

32

1667.2

42

1107.3

 

33

1598.2

43

1064.5

 

34

1532.9

44

1023.1

 

35

1470.6

60

560.3

MR730/720/700/480 Technical Manual # Revision D # issued Octoher 1995

page 13

5.0CALIBRATION

5.1INTRODUCTION

Calibration should be performed after any servicing involving the printed circuit boards. After

calibration, perform a performance check as

outlined

in

section 6.0.

 

 

 

 

Note:

For

instructions

on

disassembly

of

the

unit, refer to Section 7.0

Servicing

Information.

 

Calibration is facilitated by entering a special

Calibration

mode.

See

Appendix

Al.

 

 

There

are

only

two

adjustments

VR4

and

VR5,

the 41

°C

comparator

stage and

the

setting of

the span of

the A to D converter.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This calibration procedure may be carried out

if the

unit

is thought to

be out of calibration (E0x-E7x

error

messages

in the

display) or

if any

of the

circuit

boards

have

been

replaced

or repaired.

In particular

any repair

that

may

have

altered

the

potential

of

the

+5

or -5

volt

rails

or component

change

associated

with

the A

to D

converter

would

require

a calibration

check.

 

 

 

 

 

 

Calibration should be checked and performed after the unit has been running for at least half an hour; ie calibration performed after the unit has warmed up.

5.2EQUIPMENT REQUIRED

1) 41 °C calibration probe, available in MR700 series calibration kit (F dz P part no. 900MR548).

Models Before Serial Number 92XXAAA05495 (Revision D PCB and earlier)

2)Heater Wire module.

3) For MR480 only - jumper connector cable, which consists of two easy hooks connected in series with a 100mm length of cable and a 22K resistor.

5.3

CALIBRATION

PROCEDURE

FOR

MODELS

WITH REVISION D PCBS OR EARLIER

 

(See

product change history - section 9.0

for serial number details).

 

1)

With

models

MR730/720/700

ensure

that

a Heater

Wire module is connected, and that the Heater

 

 

Wire

switch

is

on

(Heater

Wire

On LED

should be

on).

 

2)

Plug

in the 41

°C

calibration probe.

 

 

 

3)Gain access to the adjustment potentiometers VR4 and VRS, by removing the control board from the humidifier front panel.

4)

With model

MR480

only

connect the jumper cable from pin

7 of U10

to the cathode

end of

D7 on

 

the control board.

 

 

 

 

 

 

 

5)

With the

Chamber

Temp

button held down turn on the power

switch.

Display should

show

-1-

6)

Using the

Chamber

Temp

button step through to number -4-

 

 

 

 

7)

Adjust

VR4

slowly

so

the

display just changes from vertical

to horizontal bars (|||||| to ===).

Back

 

off VR4

 

and

recheck

that

VR4 is not rotated past this display

transition

point.

 

 

8)

Using the Chamber Temp button step to number -5-

 

 

 

 

9)

Remove the 41 °C calibration probe.

 

 

 

 

10)

Adjust

VR5

for a display

reading of zero. ( 0)

 

 

 

 

11)

Calibration

is complete; do performance check (section 6.0).

 

 

 

 

MR730/720/700/480 Technical Manual # Revision D # issued October 1995

page 14 |

5.4 CALIBRATION PROCEDURE FOR MODELS WITH REVISION F PCBS OR LATER (See product change history - section 9.0 for serial number details)

1)

Plug in the 41 °C calibration probe.

2)Gain access to the adjustment potentiometers VR4 and VRS, by removing the control board from the humidifier front panel.

3)

With the Chamber Temp button held down turn

on the

power switch. Display

should

show

-1-

4)

Using the Chamber

Temp

button

step through

to

number -4-

 

 

 

5)

Starting with a vertical bar

display

adjust

VR4

so

the display changes to an all

8 display. If

VR4 is

 

rotated too far the display

becomes

all horizontal

bars

((j.||.||. thru 8.8.8. to ==).

The

correct

point is

 

where all the segments of

the all 8 display are of

equal

brightness.

 

 

 

6)

Using the Chamber

Temp

button

step to

number

-5-

 

 

 

 

7)

Remove the

41

°C

calibration probe.

 

 

 

 

 

 

 

 

8)

Adjust VRS

for

a display

reading

of

zero.

( 0)

 

 

 

 

 

 

9)

Calibration

is complete;

do

performance

check

(section

6.0)

 

 

 

MR730/720/700/480 Technical Manual # Revision D # Issued October 1995

page 15

6.0PERFORMANCE CHECK

6.1INTRODUCTION

This procedure may be used to check the operation and calibration of the MR730/720/700/480

humidifiers without dismantling the unit. This performance check should be performed

after any

 

servicing

involving

the printed

circuit

boards,

and

annually

as

part of the routine

maintenance

procedure

(see

Appendix

B).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Performance

can

be

monitored

during

the

test

by

using

the

functions

of the

Engineering

Menu.

 

See

Appendix

A2.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The

Performance

test

consists of two main parts, the Static Test and the Dynamic

Test.

 

 

 

 

For the Static Test, the

humidifier is first run with fixed inputs to check for

correct heater

plate

control.

Initially the heater plate will get

warm,

but should

be relatively cold

at the

end

of

the

first

part

of

this

test.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The

second

part

of

the

Static Test checks the over temperature protection.

At

the

end

of

this test

the

heater

plate

will

be

at

maximum

temperature.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

For

the

Dynamic

Test,

the

humidifier

with

a chamber

is fitted

with a

Heater

Wire

delivery

tube

assembly

and

a probe

assembly.

The

delivery tube

should be supported

from

above

so

that

it drops

vertically over

its entire

length

to the

top of the

chamber.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

While testing the Heated Wire models, the chamber does not require to be filled with water or have a gas

supply but the chamber inlet must be unobstructed. The purpose of this set-up is to establish an air flow through the chamber and up the delivery tube by convection.

The MR730/720 is to be tested in the Heater Wire on mode (green LED on). The non Heated Wire model MR480 is tested slightly differently. See section 6.4.

6.2PERFORMANCE CHECK MR730/720/700

Ensure

the MR730/720/700 model has a

suitable Heater Wire module connected.

See section 6.4 for testing of MR480.

 

NOTE:

Please ensure that the procedures

are followed correctly to avoid misleading test results.

6.2.1EQUIPMENT REQUIRED

1) 34.5 °C Test probe, available in MR700 series calibration kit (F & P part no. 900MR548). 2) Delivery hose and heater wire assembly (1.1 to 1.3 metre Adult).

3)Dual probe assembly.

4)A humidification chamber without scroll. (Not an MR390.)

6.2.2STATIC TEST SEQUENCE (MR730/720/700)

Connect the Heater Wire cable to the humidifier. Do not at this stage connect the probe assembly to the humidifier or the delivery tube to the humidification chamber outlet.

1)Plugina34.5 degree test probe.

2) Tum the Temperature Control knob to 33.0 + 0.2 degree and Chamber Control to 0.

3) Turn on the humidifier mains power switch.

4)Check the Temperature Control and Chamber Control setting by noting display readings during initialisation.

5) Check display reading of 34.5 + 0.2 after initialisation and that the Set Low warning light is on.

6)Push Chamber temp. button and check for 34.5 + 0.2 degree reading.

MR730/720/700/480 Technical Manual # Revision D # Issued October 1995

page 16

7) Run for 30 minutes without interruption. If mains power is interrupted test will have to be restarted.

8)After 30 minutes Check:

Heater plate cold. Less than 60 °C (hP engineering menu).

Heater Wire cold (feel).

9) Turn the humidifier main power switch off.

10) Turn the temperature control knob to 36.0 + 0.2 °C and leave Chamber Control set at 0.

11) Turn on the mains power.

12) Check temperature control knob setting during initialisation.

 

13)

Run

for

30

minutes

without

interruption.

 

 

 

 

14)

After

30

minutes Check:

 

 

 

 

 

 

 

Heater plate

hot ( Greater than 80 °C ).

 

 

 

 

 

Heater Wire hot (feel).

 

 

 

 

 

 

15)

Tum

off

the

humidifier.

 

 

 

 

 

6.2.3

DYNAMIC

TEST

SEQUENCE

(MR730/7 20/700)

 

 

 

 

1)

Remove

the

34.5 °C

Test probe and connect the

vertically

supported

delivery tube to the outlet of

 

 

the empty chamber

(any

no

scroll chamber other

than an

MR390) on

the humidifier.

2) Connect the Heater Wire cable and probe assembly to the humidifier.

3) Turn Set control to 36.0+ 0.1°C and Chamber Control to 0.

4) Turn on mains power and check settings during initialisation.

Note: At low ambient temperatures (below 22 °C) the Heater Wire under the low flow conditions of the test will warm up only slowly and may give a low temperature alarm. If this is muted the

breathing circuit will eventually warm and the humidifier will start controlling.

5) Check after 10 minutes that digital display is 36.0 + 0.3°C

6) After % hour check chamber outlet temperature is 36.0 + 2.0°C

7)Continue to run for 3 hours, then check the following:

Airway temperature 36.0 +

0.3°C

In ‘Engineering

Mode’ (see

appendix A2):

set

=

36+0.1°C

offset=

0

 

Ede

=>

0

 

Cde

=>

0

 

hp

=

>36°C

 

 

and

there are no spurious alarms.

 

 

 

 

 

 

 

 

 

8)

Rotate

temperature

control knob

to

38

and

check

for

an

Airway

Temperature

Low

alarm. (For

 

MR720

set to 40 degrees).

 

 

 

 

 

 

 

 

 

 

 

 

9)

Rotate

temperature

control knob

to

34

and

check

for

an

Airway

Temperature

High

alarm.

10)

Rotate

the chamber

control to

-2.5

and

check

that

the

set low light comes on.

 

 

11)

Check

Heater Wire

wire plug

disconnect gives

audio

alarm and

Heater Wire

alarm

light.

MPR720/720700/420 Technical Manual + Revision D

Issued October 1905

 

page

17

12) Push

the Heater Wire switch and check that

Heater Wire off gives Audio alarm and Heater Wire

alarm

light.

 

13) Disconnect the temperature probe and check the Temperature Probe LED flashes and gives an audio alarm.

14) Push the Mute button and check alarm silencing.

15) Unit is now ready for service.

6.3PERFORMANCE CHECK (MR480)

The test consists of two main parts: the Static Test and the Dynamic Test.

For the Static Test the humidifier is first run with fixed inputs to check for correct heater plate control.

Initially the heater plate will get very hot but

should be cool at the end of the

first

part

of

this

test. The

second

part of the Static Test

checks

the over

temperature protection. At

the

end

of

this

test

the

heater

plate will be at maximum

temperature.

 

 

 

 

 

 

 

 

 

 

For the

Dynamic Test,

the

humidifier

with

a

full chamber (use only MR310

chambers)

is

fitted

with a

delivery

tube

assembly

and a

probe assembly.

The delivery tube should be supported vertically.

 

NOTE:

Please

ensure

that

the

procedures

are

followed correctly to avoid

misleading

results.

 

 

6.3.1EQUIPMENT REQUIRED

1)

34.5

°C Test

probe.

 

 

 

 

 

2)

Anon

heated delivery

circuit (1.1

to

1.3

metre

Adult).

3)

Dual

temperature probe

assembly

such

as 900MR560.

4)

An MR310

humidification chamber

or

similar

scrolled reusable chamber.

6.3.2 STATIC TEST PROCEDURE (MR480)

1) Pluginthe 34.5 degree test probe.

2) Turn the temperature contro! knob to 33.0 + 0.2 degree.

3) Turn on the humidifier main power switch.

4) Check that 33.0 + 0.2 flashes on the display during initialisation.

5) Check display reading of 34.5 after initialisation (+ 0.2).

6) Push Chamber Temp. button and check for 34.5 degree reading (+ 0.2).

7) Run for 1 hour without interruption. If mains power is interrupted test will have to be restarted.

8) After 1 hour check the engineering menu (Appendix A2): Set = 33

hp = <70

9)Turn off the humidifier

10) Turn the temperature control knob to 36.0 + 0.2 degree (check correct setting is displayed when the control is adjusted).

11) Check temperature control knob setting during initialisation.

12) Run for 1 hour without interruption.

MR730/720/700/480 Technical Manual * Revision D

Issued October 1995

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