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.
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Description |
of Change |
Page Numbers |
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Affected |
GENERAL |
Rewrite and update to |
incorporate change to Rev H PCB |
various |
and version |
3.0 software |
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MR730/720/700/480 Technical Manual # Revision D * issued October 1995
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CONTENTS |
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1.0 |
MR700 |
Series General Specifications essence |
1 |
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1.1 |
Electrical |
Specifications |
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1.1.1 |
Models |
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MR730/720/700 .. |
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1.12 |
Model |
MR480 |
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„I |
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1.1.3 |
Common |
Electrical Specifications (All Models). |
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wel |
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12 |
Standards |
and |
Approvals |
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13 |
Temperature |
Control |
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14 |
Temperature |
Sensing.. |
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1.5 |
Temperature |
Display .. |
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2.0 |
Operating |
Controls |
And |
Modes |
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2.1 |
Adjustable |
Controls |
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2.1.1 |
Airway |
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Temperature |
Control |
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2.1.2 |
Chamber |
Control (Heater Wire On Mode Only). |
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3 |
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2.2 |
Push Switches |
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„3 |
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221 |
Mute Button |
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222 |
Chamber |
Temp |
Button.. |
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3 |
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2.2.3 |
Standby Button (MR700/720/730 only) ... |
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3 |
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2.24 |
Heater |
Wire |
Switch |
(MR720, |
MR730 |
only). |
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23 |
Power |
Up |
Seguences |
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4 |
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2.3.1 |
Version |
1.0 |
Software |
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2.3.2 |
Version 2.0 and Version 3.0 Software |
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24 |
Heater Wire On Mode (All models except MR480).. |
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4 |
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2.5 |
MR730/720 |
in |
Heater Wire Off |
Mode |
and MR480 .. |
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s.m. |
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2.6 |
Warm |
Up |
Mode |
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„5 |
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2.6.1 |
MR700/MR730 |
and |
MR720(version |
1.0) in Heater Wire Mode.. |
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2.62 |
MR700/MR730 |
and |
MR720(version |
1.0) |
in Non |
Heater Wire |
Mode |
and MR480... |
5 |
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2.6.3 |
MR720 |
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With Version 2.0/3.0 Software . |
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2.7 |
Standby Mode |
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2.7.1 |
MR700/MR730 |
and |
MR720 |
(Version |
1.0) |
Only. |
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~ „5 |
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2.7.2 |
MR720 |
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Standby |
Mode (Version |
2.0 |
and |
3.0 |
software only) .....................ci rsrerresserserersererses 5 |
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3.0 |
Alarms |
and |
Indicators... |
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.6 |
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3.1 |
Temperature |
Probe |
Alarm |
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6 |
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3.2 |
Alarms In Heater Wire Mode (MR700/720/730 only).. |
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6 |
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3.2.1 |
Heater |
Wire |
Alarm........ |
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6 |
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3.2.2 |
Airway |
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temperature |
High |
Alarm |
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3.2.3 |
Airway |
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temperature |
Low |
Alarm. |
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3.2.4 |
Chamber |
Temp |
High |
Alarm |
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7 |
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3.2.5 |
Chamber |
Temp |
Low |
Alarm. |
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3.2.6 |
Set |
Low |
Waming................. |
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7 |
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3.3 |
Temperature Alarms in Non Heater Wire Mode (includes MR480).. |
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8 |
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3.3.1 |
Heater |
WireAlarm......................... |
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8 |
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3.3.2 |
Airway |
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Temperature |
High |
Alarm.. |
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3.3.3 |
Airway |
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Temperature |
Low |
Alarm |
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.8 |
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3.4 |
Audio |
Alarm |
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.8 |
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3.5 |
Safety Protection (All Models)... |
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.8 |
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3.5.1 |
Temperature |
Deviations... |
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.8 |
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3.5.2 |
Microprocessor |
Watch Dog |
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4.0 |
Circuit |
Operation |
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e. |
9 |
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41 |
Introduction |
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.9 |
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4.2 |
Control Board .. |
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.9 |
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4.2.1 |
Control |
Thermistors |
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.9 |
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4.2.2 |
Input Analog Switches U8 and U9 |
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.9 |
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4.2.3 |
Analog to Digital Converter U10 b,d,e. |
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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 |
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5.1 |
Introduction ... |
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13 |
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5.2 |
Equipment Required. |
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13 |
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53 |
Calibration Procedure for Models with Revision D PCBs or earlier |
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54 |
Calibration Procedure for Models with |
Revision |
F PCBs or later... |
„14 |
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6.0 |
Performance |
Check |
ee |
veses |
. |
SS |
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6.1 |
Introduction |
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6.2 |
Performance |
Check |
MR730/720/700 |
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15 |
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6.2.1 |
Equipment |
Required .. |
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15 |
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6.2.2 |
Static Test |
Sequence (MR73 |
00) |
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15 |
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6.2.3 |
Dynamic |
Test |
Sequence (MR730/720/700 |
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16 |
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63 |
Performance |
Check |
(MR480).... |
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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 |
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72 |
Printed Circuit Board Removal .. |
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7.2.1 |
Control |
PCB |
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722 |
Power PCB |
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73 |
Replacement of Revision D Power & Control PCB |
Assemblies... |
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74 |
Heater Plate |
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7.5Fault Location
7.6Screw Torque Settings.
8.0 |
Schematics, Part Lists and Mechanical Drawings |
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8.1 |
MR700 |
Series Circuit Layout |
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Block |
Diagram |
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82 |
Component Layout - Revision H PCB |
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83 |
Component |
Layout |
- Revision |
F |
PCB.. |
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84 |
Component |
Layout |
- Revision |
D |
PCB ..... |
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8.5 |
Link Pad Locations for Programming |
Control Options - Revision H PCB |
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8.6 |
Circuit |
Diagrams |
- Revision |
H |
PCB |
Control |
PCB. |
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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 |
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9.1 |
Compatibility of Software and Hardware Versions.. |
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9.2 |
Model |
Number |
Explanation . |
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93 |
Serial |
Number |
Explanation .. |
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Appendix A. |
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conos |
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00000 |
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Al |
Calibration Mode... sine |
an |
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A2 |
Engineering |
Menu |
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eeeeeeeen eee rn |
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A2.1 |
Engineering display functions: Heater Wire Mode. |
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A22 |
Engineering Functions: Non Heater Wire Mode .... |
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A2.3 |
Integral |
Display |
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A3 |
Programming |
Control |
Options . |
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A4 |
Glossary |
of |
Abbreviations |
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A5 |
Error Codes |
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A6 |
MR700 Series |
Humidifier Serial |
Data |
Interface |
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A6.1 |
Serial |
Data |
Format |
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rire |
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A6.2 |
Status |
Information. |
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A6.3 |
Remote |
Standby .... |
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46.4 |
Serial |
Data |
Interface Connector. |
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A7 |
Revision |
F |
& |
H PCB |
Schematic |
Diagrams |
nn |
Appendix |
B |
veve |
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BI |
Recommended |
Maintenance |
Schedule................... |
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B2 |
Recommended |
Maintenance |
Schedule |
Checklist... |
....63 |
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Appendix |
C.... |
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κο. |
sous |
ce |
.6S |
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C1 |
Troubleshooting Guide For |
The |
MR700 |
Series Respiratory Humidifiers. |
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C2 |
MR700 |
Series |
Fault Flow Chart |
For No |
Go Condition |
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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 |
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- |
127V |
x |
12V |
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115V |
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100V |
+ |
10V |
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Supply |
Frequency: |
50 |
- |
60 |
Hz |
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Supply |
Current: |
1.0 |
A |
maximum |
at |
230V |
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1.9 |
A |
maximum |
at |
127V |
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2.0 |
A |
maximum |
at |
115V |
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2.4 |
A |
maximum |
at |
100V |
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Heater |
Wire Capacity: |
60 |
W |
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1.1.2MobeL MR480
Supply |
Voltage: |
230V |
+25V |
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115V |
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100V |
+10V |
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Supply |
Frequency: |
50 |
- |
60 Hz |
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Supply |
Current: |
0.7 |
A |
maximum |
at |
230V |
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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 |
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JEC601-1, |
AS3200.1, |
BS5724:Part 1, DIN |
VDE 0750 Teil 1 |
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Class |
1 |
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Type |
B |
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Drip |
Proof |
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Continuous |
Operation |
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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. |
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1.5TEMPERATURE DISPLAY
Three |
digit |
14mm |
7 segment LED (Light Emitting Diode) display. |
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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 |
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scale |
marked in |
degrees |
on |
the |
front |
panel. |
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The |
temperature |
can be |
set |
with |
a resolution |
of |
0.1 |
°C. |
The |
set |
temperature |
is flashed |
on |
the display |
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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 |
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MODE |
ONLY) |
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The |
temperature of |
the gas |
leaving |
the |
chamber |
is |
regulated |
by |
the |
Chamber |
Control |
knob, |
it sets |
the |
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difference between the chamber outlet |
temperature |
and |
the |
airway |
temperature delivered |
to |
the patient. |
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The |
setting |
of the |
Chamber |
Control, when |
added |
to |
the |
setting |
of |
the |
Temperature Control, |
determines |
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the |
chamber |
outlet |
set |
temperature. |
This |
Chamber |
Control |
has |
a linear |
range |
of |
adjustment |
from |
-5 |
to |
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+2 °C marked in one degree steps and |
can |
be |
set |
with a |
resolution |
of 0.5 |
°C. |
The |
value is |
flashed |
on |
the |
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Airway display as the control knob is |
rotated |
and |
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continues |
to |
be flashed |
for |
five |
seconds |
after the |
last |
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adjustment. |
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Every humidifier is also supplied with |
a |
fixed |
chamber |
control |
knob. |
This prevents |
inadvertent |
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adjustment of the chamber control by |
preadjusting the existing knob to the desired setting and then |
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replacing |
the |
normal |
knob |
with |
the |
fixed |
knob. |
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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: |
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Operation of this switch causes the airway temperature display to |
momentarily |
blank |
then show |
the |
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chamber |
outlet temperature. |
A |
green |
LED |
adjacent |
to |
the switch |
is enabled |
to |
indicate that this |
function |
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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. |
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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. |
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MR730/720/700/480 Technical Manual # Revision D. 3 Issued October 1995
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page |
4 |
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2.2.4 |
HEATER |
WIRE |
SwiTCH |
(MR720, |
MR730 |
ONLY) |
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|
||||
|
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. |
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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 |
||
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|
Airway |
Temperature |
display |
|
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|
Temperature Control Setting |
eg '37.0' |
is displayed |
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|||
|
Chamber |
Control |
setting |
If heater |
wire |
mode |
is selected then the |
chamber |
control setting is |
||
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|
displayed eg |
'-1.0'. |
Not applicable |
for |
MR480 |
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9 |
Software |
Version |
Number |
1.0 |
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Maximum |
Heater |
Plate Setting |
eg'110' |
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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 |
|
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|
|
All |
indicator |
LEDs are |
illuminated |
and |
'8.8.8.' |
is |
displayed on |
||||||||
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|
the |
Airway |
Temperature display |
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|||||
|
. |
Model |
Number |
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eg |
'730° |
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9 |
Software |
Version |
Number |
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eg |
'2.0' |
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||||
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. |
Temperature |
Control |
Setting |
|
eg |
'37.0' |
is |
displayed |
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|||||
|
9 |
Chamber |
Control |
setting |
|
If |
heater |
wire |
mode |
is |
selected then |
the |
chamber |
control |
setting |
||||||||
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|
is |
displayed eg '-1.0'. |
Not applicable |
for MR480 |
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||||||||
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|
Maximum |
Heater |
Plate Setting |
ερ |
110' |
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|||||
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Audio |
Beep |
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2.4 |
HEATER |
WIRE |
ON |
MODE |
(ALL |
MODELS |
EXCEPT |
MR480) |
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|
|||||||
|
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) |
|
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|
|
|
. |
|
|
|
|
|
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 |
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|
the |
airway |
temperature does not increase by 2 |
°C |
|
within |
15 |
minutes |
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|
|
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 |
|
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|
|||||||
|
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) |
|
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|
|||||||||
|
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 |
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While |
in |
standby |
|
mode: |
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||
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. |
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|||||
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 |
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|||||
3.1 |
TEMPERATURE |
PROBE |
ALARM |
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|
|||||
|
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: |
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||||
|
(a) |
--- . |
Temperature |
Probe |
not |
plugged |
in. |
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|||||||
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|
Low |
temperature (~0 |
°C) |
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|||||
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|
|
Open |
circuit |
chamber |
outlet |
probe |
|
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|
||||||
|
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|
|
Open |
circuit |
in common |
lead |
in |
probe cable. |
|
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|
|
|
(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 |
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|||||||
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|
Very high temperature (~100 °C) |
|
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|
||||||
(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. |
|
|
|
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|
||||
OR |
|
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|
|
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|
|
|
|
|
|
|
|
|
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. |
|
|
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|
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|
|
|
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|
|
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. |
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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 |
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|
control |
the |
chamber |
outlet temperature. |
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3. |
A |
third |
thermistor |
is permanently |
mounted |
in |
intimate |
contact |
with |
the heater |
plate (HP) |
(connector |
|||||||||||||||
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|
J3-1,3). This |
prevents excessive heater |
plate |
temperatures |
during |
a warm up cycle. |
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4.2.2 |
INPUT |
ANALOG |
|
SWITCHES |
U8 |
AND |
US |
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The |
1 |
by |
8 |
analog |
switch |
(U8) |
selects under processor control (PB0-3) |
various |
input signals |
and |
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|
reference |
potentials. |
Selected |
sequentially are potentials giving; (0-3): |
the position |
of |
the temperature |
set |
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|
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. |
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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. |
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|
|
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. |
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Under processor control (PB6) when the switch section |
of U9 across C22 is |
opened the output of U10b |
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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 |
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MR730/720/700/480 Technical Manual № Revision D. # issued October 1995
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page |
10 |
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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. |
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4.2.6 |
Power |
LINE INTERRUPT |
(REVISION |
H |
PCB) |
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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 |
|||||||||||||||
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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. |
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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 |
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both heaters |
to |
be |
shut |
down. |
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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 |
|
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clamped |
off |
in |
the |
event |
of |
a processor |
crash. |
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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 |
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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 |
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heater plate |
module. |
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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. |
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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 |
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UA on the control board. |
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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. |
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Тнас |
ОП |
(mounted |
on the |
heatsink) |
is |
controlled |
by |
optoisolator U12, |
which |
in |
turn |
is |
controlled |
by |
|||||||||||
Q12, |
and |
HPC. |
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Transistors Q5 and Q6 are a RS232 level driver for the serial data interface.
4.3.2 |
REVISION |
H |
PCBS |
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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. |
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|
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 |
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page |
12 |
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44 |
PROBE TEMPERATURE VERSUS THERMISTOR RESISTANCE |
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||
|
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. |
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Note: |
For |
instructions |
on |
disassembly |
of |
the |
unit, refer to Section 7.0 |
Servicing |
Information. |
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Calibration is facilitated by entering a special |
Calibration |
mode. |
See |
Appendix |
Al. |
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There |
are |
only |
two |
adjustments |
VR4 |
and |
VR5, |
the 41 |
°C |
comparator |
stage and |
the |
setting of |
the span of |
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the A to D converter. |
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This calibration procedure may be carried out |
if the |
unit |
is thought to |
be out of calibration (E0x-E7x |
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error |
messages |
in the |
display) or |
if any |
of the |
circuit |
boards |
have |
been |
replaced |
or repaired. |
In particular |
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any repair |
that |
may |
have |
altered |
the |
potential |
of |
the |
+5 |
or -5 |
volt |
rails |
or component |
change |
associated |
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with |
the A |
to D |
converter |
would |
require |
a calibration |
check. |
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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 |
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(See |
product change history - section 9.0 |
for serial number details). |
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1) |
With |
models |
MR730/720/700 |
ensure |
that |
a Heater |
Wire module is connected, and that the Heater |
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Wire |
switch |
is |
on |
(Heater |
Wire |
On LED |
should be |
on). |
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2) |
Plug |
in the 41 |
°C |
calibration probe. |
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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 |
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the control board. |
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5) |
With the |
Chamber |
Temp |
button held down turn on the power |
switch. |
Display should |
show |
-1- |
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6) |
Using the |
Chamber |
Temp |
button step through to number -4- |
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7) |
Adjust |
VR4 |
slowly |
so |
the |
display just changes from vertical |
to horizontal bars (|||||| to ===). |
Back |
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off VR4 |
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and |
recheck |
that |
VR4 is not rotated past this display |
transition |
point. |
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8) |
Using the Chamber Temp button step to number -5- |
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9) |
Remove the 41 °C calibration probe. |
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10) |
Adjust |
VR5 |
for a display |
reading of zero. ( 0) |
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11) |
Calibration |
is complete; do performance check (section 6.0). |
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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- |
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4) |
Using the Chamber |
Temp |
button |
step through |
to |
number -4- |
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5) |
Starting with a vertical bar |
display |
adjust |
VR4 |
so |
the display changes to an all |
8 display. If |
VR4 is |
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|
rotated too far the display |
becomes |
all horizontal |
bars |
((j.||.||. thru 8.8.8. to ==). |
The |
correct |
point is |
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|
where all the segments of |
the all 8 display are of |
equal |
brightness. |
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6) |
Using the Chamber |
Temp |
button |
step to |
number |
-5- |
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7) |
Remove the |
41 |
°C |
calibration probe. |
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8) |
Adjust VRS |
for |
a display |
reading |
of |
zero. |
( 0) |
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9) |
Calibration |
is complete; |
do |
performance |
check |
(section |
6.0) |
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|
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 |
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servicing |
involving |
the printed |
circuit |
boards, |
and |
annually |
as |
part of the routine |
maintenance |
procedure |
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(see |
Appendix |
B). |
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Performance |
can |
be |
monitored |
during |
the |
test |
by |
using |
the |
functions |
of the |
Engineering |
Menu. |
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See |
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Appendix |
A2. |
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The |
Performance |
test |
consists of two main parts, the Static Test and the Dynamic |
Test. |
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For the Static Test, the |
humidifier is first run with fixed inputs to check for |
correct heater |
plate |
control. |
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Initially the heater plate will get |
warm, |
but should |
be relatively cold |
at the |
end |
of |
the |
first |
part |
of |
this |
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test. |
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The |
second |
part |
of |
the |
Static Test checks the over temperature protection. |
At |
the |
end |
of |
this test |
the |
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heater |
plate |
will |
be |
at |
maximum |
temperature. |
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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 |
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its entire |
length |
to the |
top of the |
chamber. |
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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. |
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14) |
After |
30 |
minutes Check: |
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Heater plate |
hot ( Greater than 80 °C ). |
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Heater Wire hot (feel). |
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15) |
Tum |
off |
the |
humidifier. |
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6.2.3 |
DYNAMIC |
TEST |
SEQUENCE |
(MR730/7 20/700) |
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1) |
Remove |
the |
34.5 °C |
Test probe and connect the |
vertically |
supported |
delivery tube to the outlet of |
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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. |
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8) |
Rotate |
temperature |
control knob |
to |
38 |
and |
check |
for |
an |
Airway |
Temperature |
Low |
alarm. (For |
||
|
MR720 |
set to 40 degrees). |
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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. |
|
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|
|||||
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 |