VIASYS 750PSV Service Manual

Service Manual

Bear Cub 750PSV

© Copyright 2004, VIASYS Healthcare Critical Care

L2342 Revision B November 2004

2 Bear Cub 750PSV

Revision History

Date Revision Pages Changes

June 2003 A All Release

May 2004 B All Release manual in VIASYS Healthcare

template using VIASYS Healthcare Critical
Care nomenclature.

L2342 Revision B November 2004

Service Manual 3

Contact and Ordering Information

United States, Latin America, Asia Pacific:

Sales, Service and Clinical Support:
VIASYS Healthcare
Critical Care Division
22705 Savi Ranch Parkway
Yorba Linda, CA 92887
Phone: [phone]
[phone]
Fax: [phone]

www.VIASYShc.com

United Kingdom:

Sales, Service and Clinical Support:
VIASYS Healthcare
3 Welton Rd.
Warwick,
CV34 5PZ
Phone: [phone]
Fax: [phone]

Europe

Sales and Customer Service Technical Service

VIASYS Healthcare VIASYS Healthcare
Critical Care Division Leibnizstrasse 7
22705 Savi Ranch Parkway D-97204 Hoechburg
Yorba Linda, CA 92887 Germany
Phone: [phone] Phone [phone] – 0
[phone] Fax:[phone]
e-mail: [e-mail]
website: www.VIASYShc.com

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4 Bear Cub 750PSV

CAUTION

Federal law (USA) restricts this device to sale by or on the order of a physician.

CAUTION

Not suitable for use in the presence of flammable anesthetics.

CAUTION

Service and/or repair of this instrument is restricted to VIASYS Healthcare authorized
or VIASYS Healthcare Trained Personnel only.

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Service Manual 5

Warranty

The Bear Cub 750PSV is warranted to be free from defects in material and
workmanship and to meet the published specifications for One (1) year from date of
shipminent.

The liability of VIASYS Healthcare, Critical Care Division, (referred to as the
Company) under this warranty is limited to replacing, repairing or issuing credit, at
the discretion of the Company, for parts that become defective or fail to meet
published specifications during the warranty period; the Company will not be liable
under this warranty unless (A) the Company is promptly notified in writing by Buyer
upon discovery of defects or failure to meet published specifications; (B) the
defective unit or part is returned to the Company, transportation charges prepaid by
Buyer; (C) the defective unit or part is received by the Company for adjustment no
later than four weeks following the last day of the warranty period; and (D) the
Company’s examination of such unit or part shall disclose, to its satisfaction, that
such defects or failures have not been caused by misuse, neglect, improper
installation, unauthorized repair, alteration or accident.

Any authorization of the Company for repair or alteration by the Buyer must be in
writing to prevent voiding the warranty. In no event shall the Company be liable to
the Buyer for loss of profits, loss of use, consequential damage or damages of any
kind based upon a claim for breach of warranty, other than the purchase price of any
defective product covered hereunder.

The Company warranties as herein and above set forth shall not be enlarged,
diminished or affected by, and no obligation or liability shall arise or grow out of the
rendering of technical advice or service by the Company or its agents in connection
with the Buyer's order of the products furnished hereunder.

Limitation of Liabilities

This warranty does not cover normal maintenance such as cleaning, adjustment or
lubrication and updating of equipment parts. This warranty shall be void and shall not
apply if the equipment is used with accessories or parts not manufactured by the
Company or authorized for use in writing by the Company or if the equipment is not
maintained in accordance with the prescribed schedule of maintenance.

The warranty stated above shall extend for a period of One (1) year from date of
shipment, with the following exceptions:

1. Components for monitoring of physical variables such as temperature,
pressure, or flow are warranted for ninety (90) days from date of receipt.

2. Elastomeric components and other parts or components subject to
deterioration, over which the Company has no control, are warranted for sixty
(60) days from date of receipt.

3. Internal batteries are warranted for ninety (90) days from the date of receipt.

The foregoing is in lieu of any warranty, expressed or implied, including, without
limitation, any warranty of merchantability, except as to title, and can be amended
only in writing by a duly authorized representative of the Company.

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6 Bear Cub 750PSV

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Service Manual 7

Contents

Revision History .................................................................................... 2

Contact and Ordering Information ...............................................................................3

Warranty .........................................................................................................................5

Limitation of Liabilities.................................................................................................... 5

Contents .........................................................................................................................7

List of Figures ................................................................................................................9

List of Tables................................................................................................................ 11

Chapter 1: Specifications ...................................................................13

Modes............................................................................................................................ 13

Controls ........................................................................................................................13

Alarms...........................................................................................................................15

Monitors........................................................................................................................17

Preset Values ............................................................................................................... 19

Emissions/Susceptibility............................................................................................. 19

Outputs .........................................................................................................................19

Inputs ............................................................................................................................20

Physical Dimension and Shipping Information......................................................... 20

Environmental Specifications..................................................................................... 21

Method of Sterilization/Disinfection ........................................................................... 21

Cleaning........................................................................................................................22

Sterilization...................................................................................................................22

Chapter 2: Theory of Operation .........................................................23

Overview .......................................................................................................................23

Ventilator pneumatics - General description............................................................. 25

Gas Inlet Conditioning................................................................................................. 25

Blender.......................................................................................................................... 25

Flow Control Valve....................................................................................................... 25

AOPR Valve/Sub-Ambient Valve/ Dump Solenoid ....................................................26

Auxiliary Gas Outlet..................................................................................................... 26

Pressure Control System ............................................................................................26

Exhalation Valve .......................................................................................................... 27

Flow Sensor.................................................................................................................. 27

Ventilator Electronics ..................................................................................................27

Power Supply ...............................................................................................................28

Ventilator Software ......................................................................................................28

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Chapter 3 OVP Recommended Service ........................................... 29

Operational Verification .............................................................................................. 29

Equipment Required.................................................................................................... 29

Test Procedures........................................................................................................... 32

Exterior Inspection and Cleaning............................................................................... 34

Exterior Cleaning ......................................................................................................... 34

Plugs and Cables ........................................................................................................ 34

OVP Checklist .............................................................................................................. 35

Verification Steps......................................................................................................... 35

Chapter 4 Calibration (for software releases 2 and 3 only)........... 37

Introduction .................................................................................................................. 37

Pressure Transducers and Flow Control Valve Calibration .................................... 38

Air and O2 Regulator Balance..................................................................................... 41

Objective...................................................................................................................... 41

Equipment ................................................................................................................... 41

Requirements .............................................................................................................. 41

Chapter 5 Schematics and Assemblies ........................................... 45

Chapter 6 Troubleshooting ................................................................ 81

Chapter 7 Removal & Replacement.................................................. 85

Interior Access ............................................................................................................. 85

Flow Valve Assembly Removal .................................................................................. 85

Control PCB Removal.................................................................................................. 85

Display PCB Removal.................................................................................................. 86

Air/O2 Regulator Removal ........................................................................................... 86

Blender Removal.......................................................................................................... 86

Exhalation Valve Removal .......................................................................................... 86

Chapter 8 Preventive Maintenance................................................... 87

Replacement Parts....................................................................................................... 87

Recommended Service Procedure............................................................................. 87

Exterior Inspection ...................................................................................................... 88

Interior Inspection........................................................................................................ 88

Specifications............................................................................................................... 88

Calibration and Verification Procedure ..................................................................... 89

Ground Resistance Test.............................................................................................. 89

Current Leakage Test .................................................................................................. 89

Operational Verification Procedure............................................................................ 89

Chapter 9 RS-232 Protocol............................................................... 93

Scope ............................................................................................................................93

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Hardware Definition .....................................................................................................93

Pin Assignment............................................................................................................ 94

Software Protocol ........................................................................................................ 95

Continuous Output (Default Mode) .............................................................................. 95

Data Upon Request .....................................................................................................95

Data Format................................................................................................................. 95

Chapter 10 Parts List........................................................................ 105

Chapter 11 Repackaging Instructions .............................................107

General........................................................................................................................ 107

Packaging Instructions ............................................................................................. 107

Procedure ................................................................................................................... 107

Addendum A: Release 4 Software ................................................... 109

Addendum B: Bear Cub 750 PSV Infant Pediatric Ventilator System111

Index ................................................................................................... 113

List of Figures

Figure 2-1: Top Level Block Diagram.................................................................. 23

Figure 2-2: Pneumatics System Schematic........................................................ 24

Figure 3-1: Bear Cub 750 US with Patient Circuit .............................................. 33

Figure 5-2: .............................................................................................................. 46

Figure 5-3: .............................................................................................................. 47

Figure 5-4: .............................................................................................................. 48

Figure 5-5: .............................................................................................................. 49

Figure 5-6: .............................................................................................................. 50

Figure 5-7: .............................................................................................................. 51

Figure 5-8: .............................................................................................................. 52

Figure 5-9: .............................................................................................................. 53

Figure 5-10: ............................................................................................................ 54

Figure 5-11: ............................................................................................................ 55

Figure 5-12: ............................................................................................................ 56

Figure 5-13: ............................................................................................................ 57

Figure 5-14: ............................................................................................................ 58

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10 Bear Cub 750PSV

Figure 5-15:............................................................................................................. 59

Figure 5-16:............................................................................................................. 60

Figure 5-17:............................................................................................................. 61

Figure 5-18:............................................................................................................. 62

Figure 5-19:............................................................................................................. 63

Figure 5-20:............................................................................................................. 64

Figure 5-21:............................................................................................................. 65

Figure 5-22:............................................................................................................. 66

Figure 5-23:............................................................................................................. 67

Figure 5-24:............................................................................................................. 68

Figure 5-25:............................................................................................................. 69

Figure 5-26:............................................................................................................. 70

Figure 5-27:............................................................................................................. 71

Figure 5-28:............................................................................................................. 72

Figure 5-29:............................................................................................................. 73

Figure 5-30:............................................................................................................. 74

Figure 5-31:............................................................................................................. 75

Figure 5-32:............................................................................................................. 76

Figure 5-33:............................................................................................................. 77

Figure 5-34:............................................................................................................. 78

Figure 5-35 ..............................................................................................................79

Figure 6-1: Troubleshotting Decision Tree .......................................................... 81

Figure 8-1: Ventilator Back Panel ........................................................................ 90

Figure 11-1: Packaging System Diagram ........................................................... 108

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Service Manual 11

List of Tables

Table 3-1: Standard Settings................................................................................ 30

Table 3-2: Rate ...................................................................................................... 30

Table 3-3: Exhalation Time and I/E Ratio Table.................................................. 30

Table 4-1: Control PCB Transducer Calibration................................................. 38

Table 4-2: Calibration ........................................................................................... 39

Table 4-3: Diagnostic Function............................................................................ 40

Table 4-4: Inspiratory Flow Calibration............................................................... 41

Table 4-5: Regulator Balance............................................................................... 42

Table 4-6: Standard Test Settings ....................................................................... 43

Table 6-2: Troubleshooting................................................................................... 82

Table 9-1: Pin Assignment .................................................................................... 94

Table 9-2: Alternate Pin Assignment.................................................................... 94

Table 9-3: Valid Requests Received by the Ventilator....................................... 96

Table 9-4: Valid Message Transmitted by the Ventilator ................................... 96

Table 9-5: Real Time Data .................................................................................... 97

Table 9-6: Adult Ventilator Control Settings....................................................... 98

Table 9-7: Adult Ventilator Alarm Settings / Status ........................................... 99

Table 9-8: Adult Ventilator Monitor Status ....................................................... 100

Table 9-9: Infant Ventilator Control Settings .................................................... 101

Table 9-10: Infant Ventilator Alarm Settings/Status......................................... 102

Table 9-11: Infant Ventilator Monitor Status..................................................... 103

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Chapter 1: Specifications

Modes

A/C

In the Assist/Control position, a mechanical breath is delivered with each inspiratory
effort, provided the patient satisfies the assist sensitivity criteria. If the patient does
not meet the assist sensitivity criteria, the ventilator automaticallydelivers breaths
according to the Ventilator Rate control. Mechanical breaths may then be either
patient initiated (assisted) or ventilator initiated (controlled).

SIMV/IMV

In the SIMV/IMV position, a combination of mechanical and spontaneous breath
types is available. Mechanical breaths, either assisted or controlled, are delivered at
the set ventilator rate while all other breaths are spontaneous. Disabling the assist
sensitivity mechanism. or removing the flow sensor from the ventilator, will cause the
equivalent of IMV mode of ventilation to exist.

CPAP

In the CPAP position, the Base Flow control establishes the continuous flow
available for spontaneous breathing.

STANDBY

The STANDBY position discontinues all electrical controls and functions with the
exception of the charging system for the internal battery.

NOTE

If the ventilator is connected to air and O2 sources, blended gas will circulate while
ventilator is in the STANDBY position, making gas available from the Auxiliary Gas
Outlet. The amount of gas flow circulating is determined by the Base Flow setting.

Controls

Rate

Range: 1 to 150 BPM

Resolution: 1 from 1 to 100BPM

2 from 100 to 150 BPM

Tolerance: Greater of ± 1 BPM or 0.02 seconds applied to the Breath

Interval

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Inspiratory Time

Range: 0.10 to 3.0 seconds

Resolution: 0.01 from 0.10 to 0.50 seconds

0.02 from 0.50 to 1.70 seconds

0.05 from 1.70 to 3.00 seconds

Accuracy: ± 0.02 seconds from 0.10 to 0.50 seconds

± 0.025 seconds from 0.50 to 3.00 seconds

Inspiratory Flow

Range: 1 to 30 L/min

Resolution: 0.5 L/min from 1 to 10 L/min

1.0 L/min from 10 to 30 L/min

Accuracy: Pressures 0 to 60 cmH2O: ± 0.5 L/min or ± 10% of setting,

whichever is greater.

Pressure 60 to 72 cmH2O: ± 0.5 L/min or + 10%/- 15% of

setting, whichever is greater.

Baseline Flow

Range: 1 to 30 L/min

Resolution: 0.5 L/min from 1 to 10 L/min

1.0 L/min from 10 to 30 L/min

Accuracy:Pressures 0 to 60 cmH2O: ± 0.5 L/min or ± 10% of setting, whichever is

greater.

Pressure 60 to 72 cmH2O: ± 0.5 L/min or + 10%/- 15% of

setting. Whichever is greater

Volume Limit™

Range: 5 to 300 ML

Resolution: 1 ML from 5 to 50 ML

2 ML from 50 to 150 ML

5 ML from 150 to 300 ML

Accuracy: ± 2 ML or ± 10% of setting, whichever is greater

PEEP

Range: 0 to 30 cmH2O

Resolution: 1 cmH2O

Repeatability: ± 1 cmH2O or ± 5%, whichever is greater

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Service Manual 15

Inspiratory Pressure

Range: 0 to 72 cmH2O

Resolution: 1 cmH2O from 0 to 30 cmH2O

2 cmH2O from 30 to 72 cmH2O

Repeatability: ± 1 cmH2O or ± 5% whichever is greater. Breath to breath

Manual Breath

Range: X1

Assist Sensitivity

Range: 0.2 to 5.0 L/min

Resolution: 0.2 at 0.2 L/min increasing to 0.5 at 5.0 L/min

Accuracy:Not a calibrated scale, minimum setting accuracy is ± 0.1 L/min

Over Pressure Relief

Range: (Pressure at the patient wye): 15

to 75 cmH2O

Resolution: 2 cmH2O stability (repeatability) ±4 cmH2O

%02 Blending

Range: 21 to 100% Oxygen concentration

Resolution: 1%

Accuracy: ± 3% oxygen

APNEA Interval

Range: 5, 10, 20, or 30 seconds

Accuracy: ± 1 second

Alarms

Alarm Loudness

Range: Min. to Max. 60 to 75 db(A)

High Breath Rate

Range: 3 to 255 BPM

Low PEEP/CPAP

Range: -5 to 30 cmH2O

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16 Bear Cub 750PSV

Low Inspiratory Pressure

Range: 1 to 65 cmH2O

Patient Circuit

LED On/Off

Failed to Cycle

LEd On/Off

Low Gas Supply

LED On/Off

Apnea

LED On/Off

Settings Incompatible

LED On/Off

Pressure Settings Incompatible

LED On/Off

Prolonged Inspiratory Pressure

LED On/Off

Flow Sensor

LED On/Off

Low Battery

LED On/Off

Alarm Silence

60 seconds

Visual Reset

Push Button

High Pressure Limit

Range: 10 to 75 cmH2O

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Service Manual 17

Line Power

Green/Red LED

Monitors

Total Breath Rate

Range: 0 to 255 BPM

Resolution: 1 BPM from 0 to 100 BPM

2 BPM from 100 to 150 BPM

3 BPM from 150 to 255 BPM

Exhalation Minute Volume

Range: 0 to 30.0 L/min

resolution: 0.01 L/min from o to 1.00 L/min

0.02 L/min from 1 to 2.00 L/min

0.05 L/min from 2 to 5.0 L/min

0.10 L/min from 5 to 10.0 L/min

0.20 L/min from 10 to 30.0 L/min

Accuracy: Accuracy of the exhaled minute volume is a function of both

volume and breath rate. To evaluate the performance of this
monitor the accuracy of both tidal volume and breath rate must
be combined

Exhaled Tidal Volume

Range: 0 to 500 ML

Resolution: 0.1 ML from 0.0 to 99.9 ML

1.0 ML from 100 to 500 ML

Accuracy: ± 1 ML or ± 10%, whichever is greater

% of Tubing Leakage

Range: 0 to 100%

Resolution: 1%

Accuracy: ± 2% or ± 1 ML

Inspiratory Time

Range: 0 to 3.10 seconds

Resolution: 0.01 seconds

Accuracy: ± 0.02 seconds

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18 Bear Cub 750PSV

Expiratory Time

Range: 0 to 99.9 seconds

Resolution: 0.01 seconds from 0 to 99.9 seconds

0.10 seconds from 10.0 to 99.9 seconds

Accuracy: ± 0.02 seconds

I:E Ratio

Range: 9.9:1 to 1:9.9

Accuracy: ± 0.1 or ± 20 mseconds, whichever is greater

Peak Inspiratory Pressure

Range: 0 to 99 cmH2O

Resolution: 1 cmH2O

Accuracy: ± 2 cmH2O or ± 5% of reading, whichever is greater

Mean Airway Pressure

Range: 0 to 75 cmH2O

Resolution: 0.5 cmH2O

Accuracy: ± 2 cmH2O or ± 3% of reading, whichever is greater

Inlet O2 Pressure

Range: 0 to 100 PSIG

Resolution: 1 PSIG

Accuracy: ± 5 PSIG

Proximal Airway Pressure

Range: -10 to 100 cmH2O

Resolution: 1 cmH2O

Accuracy: ± 1 cmH2O from -10 to 20 cmH2O

± 2 cmH2O from 20 to 65 cmH2O

± 3 cmH2O from 65 to 100 cmH2O

Hourmeter

Range: 0 to 99,999 hours

Resolution: 0.1 hour

Accuracy: ± 2% of reading

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Service Manual 19

Breath Type (Patient Initiated)

LED

Test

Push Button

Battery

LED On/Off

Preset Values

Minimum Expiratory Time 150 milliseconds

Maximum Inspiratory Time 3.10 seconds

Maximum settable I:E Ratio 4:1

Model 9300

Classification Class 1

Degree of Protection

Electric Shock Type B

Harmful Ingress of Water None (Ordinary Equipment)

Degree of Safety of Application

in Presence of Flammable Anesthetics None

Mode of Operation Continuous

Emissions/Susceptibility

This ventilator has been tested to conform to the following specifications:

MIL-STD-461D:1993,MIL-STD-462D:1993, EN55011:1991, IEC 1000-4-2:1994, IEC
1000-4-3:1994, IEC 1000-4-4:1994, IEC 1000-4-5:1994, QUASI-STATIC:1993

This ventilator is designed and manufactured to comply with the safety requirements
of IEC 601-1, IEC 601-2-12, CAN/CSA-C22.2 No. 601.1-M90, and UL 2601-1.

Outputs

Digital

(see Section 10, Page 1) RS-232 Bi-Directional

Analog

Proximal Pressure -10 to 100 cmH2O, 1 cmH2O/25 mv

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20 Bear Cub 750PSV

Proximal Inspiratory/Expiratory Flow -40 (expiratory) to 40 (inspiratory) L/min, 1
L/min/50 mv

Breath Phase 1 “Logic” signal; 0, 5V

Remote Nurse Call 0.5 amps max at 24 vdc max

Pneumatic

Auxiliary Blended Gas Outlet 7 to 17 psig, 0 to 8 L/min

Inputs

Electrical

Supply Ratings

Voltage: 100V 80 to 110 VAC

120V 96 to 132 VAC

220V* 176 to 242 VAC

240V 192 to 264 VAC

Current: 100V 1.0 A maximum

120V 1.0 A maximum

220V 0.5 A maximum

240V 0.5 A maximum

Frequency: 100V 50/60 Hz

120V 50/60 Hz

220V 50/60 Hz

240V 50/60 Hz

Fuses: 100/120V T 0.5 A, 5 x 20 mm

230/240V T 0.25 A, 5 x 20 mm

* For 220V operation, set the power entry module selector switch to 230V setting.

Pneumatic

Oxygen and Air 30 to 80 psig, 50 L/min Supply Ratings

Physical Dimension and Shipping Information

Ventilator Weight 27 lbs., 12 kg

Graphics Display Weight 5.5 lbs.

Pedestal Stand Weight 9 lbs.

Compressor Weight 110 lbs.

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Service Manual 21

Ventilator Dimensions 13.5" W x 10" D x 11" H

Graphics Display Dimensions 13" W x 2.5" D x 9.5" H

Pedestal Stand Dimensions 24" x 40.5" H

Compressor Dimensions 22"W x 21.5"D x 36" H

Shipping Weight Including Ventilator 38 lbs.

Graphics Display 11 lbs.

Pedestal Stand 12 lbs.

Compressor 122 lbs.

Shipping Dimensions

Ventilator 18" W x 18" D x 19" H

Graphics Display 16" W x 13" D x 11" H

Pedestal Stand 25" W x 5" D x 45" H

Compressor 26" W x 22" D x 40" H

Environmental Specifications

Temperature

Storage and Shipping -40 to 158 ºF (-40 to 70 ºC)

Checkout and Operating 50 to 104 ºF (10 to 40 ºC)

Altitude

Checkout, Operating,
Transport and Storage 0 to 9,000 feet (14.7 to 10.5 PSIA/760 to 543 mm Hg)

Humidity

Storage and Shipping 0 to 99% Relative Humidity — Non-condensing

Checkout and Operating 0 to 95% Relative Humidity — Non-condensing

Method of Sterilization/Disinfection

NOTE

See also the BEAR CUB™ 750vs Infant Ventilator Instruction Manual Cleaning and
Maintenance (section 7)

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22 Bear Cub 750PSV

Cleaning

External Surfaces

All external surfaces of the ventilator shall be able to be wiped clean with the
following compounds:

A. Isopropyl Alcohol

B. Chlorine Compounds Maximum Concentration: 1:10

C. Quaternary Ammonium Compounds Maximum Concentration: 1:500

NOTE

These compounds are diluted by volume in water.

Sterilization

All parts of the ventilator that can come in contact with the patient expiratory gas and
all parts of the breathing circuit external to the ventilator shall be sterilizable or
disposable.

Methods of Sterilization

Ethylene oxide, maximum temperature 130 ºF (54 ºC)

Steam sterilization, maximum temperature 250 ºF (121 ºC)

Liquid Sterilization

1. Cidex

Minimum sterilization cycles before part replacement:

1. Patient Circuit, Exhalation Manifold:

Ethylene Oxide 240 cycles

Steam Sterilization 240 cycles

Liquid Sterilization 240 cycles

2. Flow Sensor:

Ethylene Oxide 6 months

Liquid Sterilization 6 months

Pasteurization (using mesh bag) 6 months

3. All other sterilization components:

Ethylene Oxide 120 cycles or 1 year

Steam Sterilization 120 cycles or 1 year

Liquid Sterilization 120 cycles or 1 year

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Service Manual 23

Chapter 2: Theory of Operation

Overview

This section describes the operating theory of the BEAR CUB™ 750vs Infant
Ventilator. The BEAR CUB™ 750vs ventilator can be classified as a micro­processor controlled, time cycled, pressure limited, dual flow, neonatal/pediatric
critical care ventilator. Breaths are initiated either by the ventilator (controlled), by
patient activity (assisted), or by the operator (manual).

The top level block diagram (figure 2-1) graphically illustrates the overall structure of
the ventilator.

Figure 2-1: Top Level Block Diagram

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Figure 2-2: Pneumatics System Schematic

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Service Manual 25

Ventilator pneumatics - General description

Figure 2-2 shows the schematic diagram of the BEAR CUB™ 750vs Pneumatics
System. The pneumatics interface to the electronics is achieved using various
actuators (solenoids) and transducers. The Pneumatics System consists of eight (8)
main subsystems: Gas Inlet and Conditioning, Oxygen Blender System, Flow
Control, Sub-Ambient/Overpressure Relief system, Exhalation Valve/Pressure
Control, Pressure Monitoring, the Proximal Airway Purge System, and the Auxiliary
Gas Outlet.

Gas Inlet Conditioning

Compressed air and oxygen sources, supplied in the pressure range of 30 to 80
psig, are connected to the standard DISS male-threaded fittings on the back panel of
the ventilator.

Incoming air passes through a coalescing filter housed in the Air Inlet Water Trap.
Particulate matter down to .3 micron in size, and aerosols down to .75 micron, are
trapped. Both gases, air and O2, pass through sintered metal filters.

Supply pressures are monitored and displayed by the ventilator via pressure
transducers and the system electronics. The system will trigger an alarm if either Air
or O

pressure drops below 24(±2) psig, and the alarm will reset when the pressures

2

are above 30 psig.

From the Air Inlet Water Trap and internal filters, the air and oxygen enter the in-line,
one way Check Valves which prevent flow from exiting through an inlet if that source
is removed.

Blender

Air and O2 pressure are regulated to 17 psig and are balanced to each other for
accurate blending of gases in the O

In the event of a failure of either of the supply gases, one of a pair of crossover
check valves will open to permit continued operation. Oxygen blending will not be
maintained in this condition, and the patient gas flow and pressure may decrease, by
less than 10%, depending on settings.

To ensure accurate oxygen blending at low patient flow rates, a bleed valve
maintains a minimum flow through the blender.

Flow Control Valve

blender.

2

Two flow control valves are switched by a solenoid valve to create Inspiratory and
Base Flow. Each valve controls flow from 1 to 30 L/min. Each flow control valve is
geared to a potentiometer. The potentiometer provides an electronic signal to the
microprocessor; this flow is then displayed on the front panel corrected to set
barometric pressure.

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26 Bear Cub 750PSV

NOTE

The Inspiratory Flow and Base Flow displayed on the Front Panel are independent of
the flow readings taken by the flow sensor.

AOPR Valve/Sub-Ambient Valve/ Dump Solenoid

Maximum pressure to the patient can be limited using the Adjustable/Over Pressure
Relief valve. The mechanical, user adjustable, pressure relieving valve can be set
from 15 cmH
breathe air through the Sub-Ambient valve.

A Dump Solenoid is activated upon detection of an obstruction in the expiratory leg
of the patient circuit. Activation of the solenoid opens the Dump Valve to the
atmosphere. The solenoid is controlled by software which monitors system
pressures. Depending upon flow rate, patient circuit pressure will drop to 5 cmH
or less.

O to 75 cmH2O. A patient effort of -3 cmH2O allows the patient to

2

O

2

Auxiliary Gas Outlet

The auxiliary gas outlet provides blended gas for use with a nebulizer, or for manual
ventilation. The connection of auxiliary gas is achieved via a DISS O
inhibit overpressure in the system due to a mistaken connection to high pressure
oxygen supply, a check valve in line allows only one direction of flow. Auxiliary gas
flow levels can range from 0 to 8 L/min. This flow will not be interrupted by a
disruption in electrical power (therefore, use of a manual resuscitation bag could be
initiated if needed).

Pressure Control System

The BEAR CUB™ 750vs Infant Ventilator ventilates the patient between two
pressure levels: Positive End Expiratory Pressure (PEEP) and Peak Inspiratory
Pressure (PIP). Inspiratory Pressure must always be above the PEEP pressure for
ventilation to occur. The PIP pressure is manually set by the user at a level of 0 to
72 cmH
cmH
exhalation assist jet venturi compensates for flow resistance in the exhalation limb of
the patient circuit to allow 0 cmH
less than 4 cmH
be set appropriately to prevent negative patient circuit pressures.

The patient circuit has a proximal airway line for monitoring patient pressure. This
proximal airway line provides a link to the control electronics and software. It also
functions as a pneumatic servo control line to the exhalation valve. Only tubing that
is 1/8 inch in diameter is to be used in the proximal airway system. Any other
diameter tube may cause patient circuit pressure to become less stable.

O (measured at the patient wye). The PEEP valve can be set from 0 to 30

2

O. A solenoid valve switches reference pressure to the Exhalation Valve. An

2

O PEEP setting at up to 10 L/min of Base Flow (to

2

O at 20 L/min). At low levels of Base Flow, the PEEP control must

2

fitting. To

2

A purge flow (100ml/min) of blended gas through the proximal airway tube is used to
prevent the migration of moisture and patient contamination into the ventilator.

L2342 Revision B November 2004

Service Manual 27

Exhalation Valve

The Exhalation Valve regulates flow out of the patient circuit. Exhaled patient gases
flow through the expiratory leg of the patient circuit, past the Exhalation Valve
diaphragm and seat, and out to the atmosphere. The Exhalation Valve is a
pneumatic servo controlled regulator. Within the Exhalation Valve, Proximal pressure
and Control pressure (which alternates between PIP and PEEP reference pressure
depending on the breath phase) are separated by a Control diaphragm. If Control
pressure is higher than Proximal pressure, the Control diaphragm will move the
control pin to close the Exhalation Valve diaphragm. When Proximal pressure
equals PIP/PEEP Control pressure, the diaphragm will open slightly to maintain the
PIP/PEEP level. At exhalation, Control pressure drops to PEEP reference pressure
which causes the Control diaphragm to retract the control pin opening the Exhalation
Valve diaphragm. Proximal pressure then drops to the PEEP level and stabilizes.

Flow Sensor

The BEAR CUB™ 750vs Infant Ventilator flow sensor reads gas flow while sensing
flow direction. The flow is calibrated to 37 °C, ambient pressure, and assumes 100%
humidity. Inhaled flows, exhaled flows, and volumes are monitored with control
electronics through the flow sensor. The flow sensor enables the ventilator to trigger
a breath based upon inspired flow. The patient effort (in L/min) required to initiate a
breath can be adjusted (.2 to 5 L/min) using the assist sensitivity setting. The flow
sensor also enables the ventilator to display on the front panel the percentage of
endotracheal tube leak based upon inhaled and exhaled volume measurements.

The flow sensor operates on the principle of hot wire anemometry. The hot wire flow
sensing system is a constant temperature device. The bidirectional operation is
achieved with two platinum wires. The two wires are positioned in the same plane
with a pin installed between them. The upstream wire will cool more rapidly than the
downstream wire. Therefore more current will be required to maintain a constant
preset temperature. The electronics interprets this higher current in the upstream
wire to determine both flow and flow direction. This measured flow rate is then
integrated over time by the ventilator’s microprocessor to yield inhaled and exhaled
volumes.

The flow sensor reads from 0.2 to 40 L/min, calibrated from 0.2 to 25 L/min, and
indicates to 40 L/min. Each Flow Sensor Cable Assembly contains an electronic
memory circuit (an E2PROM) which stores calibration data for the unit. Therefore,
the sensor will function with the electronic circuit of any BEAR CUB™ 750vs Infant
Ventilator without the need for a system calibration.

Ventilator Electronics

The major components of the electronics system include the Display PCB, the
Control PCB, and the Power Supply.

The Display circuit board is the user interface for the ventilator electronics. Ventilator
controls and alarms are set by the clinician, and Monitors feed current ventilator
status back to the display.

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28 Bear Cub 750PSV

The Control circuit board includes the Monitor MCU and Control MCU. The Control
board drives the system solenoids which control breath phase, flow, and pressure.
This is achieved using front-panel settings from the display board, as well as
incorporating its own real-time pressure and flow readings. The Control board also
enables bidirectional (digital) communication to the optional Graphic Display in order
to chart ventilator data. Also, analog outputs proportional to pressure and flow, plus
a breath phase signal are provided to the back panel. The electronics to drive and
read the flow sensor are also contained on the Control PCB.

Power Supply

The Power Supply converts the AC line voltage to DC voltages for the electrical
system. AC line voltages of 100, 120, 230, and 240 volts (at frequencies from 50 to
60 Hertz) can be used as input power. Five DC voltages are used in the ventilator
electronics: 5, 7, 10, -10 and 22 VDC. All power levels that are high enough to pose
an ignition hazard in the presence of oxygen concentrations greater than 21% are
housed in a separate enclosure from the rest of the system. If input power fails, a 12
volt rechargeable, sealed, lead-acid battery is included to provide a minimum of 30
minutes of ventilator operation. A two-level battery charger circuit is contained on
the Power Supply PCB in order to keep the battery on continuous charge whenever
the ventilator is plugged into an AC outlet.

Ventilator Software

The BEAR CUB™ 750vs Infant Ventilator is a shared processor system,
incorporating two Motorola 68HC11 microcontroller units (MCU), the Monitor and the
Controller. Each processor, and thereby its software, have specific and duplicated
tasks. Each processor is based on a 2.5 m-sec timer interrupt, referred to as a ‘tick.’
The Controller directs basic control of the ventilator based on operational settings
communicated from the Monitor MCU, as well as on pressure transducer, and flow
sensor data read on its own 8 bit Analog to Digital (A/D) converter. The Monitor has
the following functions: (1) reads the front panel switches, back panel switches, and
potentiometers, (2) monitors ventilator performance as well as the performance of
the Controller MCU, (3) transmits front panel status to the Controller, (4) receives
performance data back from the Controller, and (5) transmits display data and
annunciator status to the front panel.

During power-up, both processors perform RAM (Random Access Memory), and
ROM (Read Only Memory) tests to verify integrity of these two memory systems.
Solenoid and Control Potentiometer continuity are also tested during power-up by
the Control and Monitor processors respectively. Continuous communication checks
between the two processors are used to verify functionality of each sub-system. If
an error is detected, either processor has the ability to shutdown the ventilator while
enabling the audible and visual Failed to Cycle alarms. These systems, among
others, are provided to reduce the possibility of a software/hardware error leading to
an undetected hazardous condition.

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Service Manual 29

Chapter 3 OVP Recommended Service

Operational Verification

Operational Verification should be performed between patient use or a minimum of
once each month. Verification may be done by a qualified operator, Allied Healthcare
Trained Hospital Service Technician or Allied Healthcare Technician. Verification is
intended to be done in the hospital. If done by an Allied Healthcare Technician,
there will be a charge.

Certain procedures such as a verification of the alarm circuits should be performed at
least once every 24 hours that the unit is in clinical use. Refer to the BEAR CUB™
750vs Infant Ventilator instruction manual for details.

Do not use the ventilator unless it passes all the steps in the Operational Verification
Procedure.

Equipment Required

Infant Test Lung P/N 52000-40027

Patient Circuit P/N 50000-01147

Oxygen Analyzer

Rubber Stopper

Stop Watch

CAUTION

If any of the following procedures fail to producer the results as outlined in this
document, disconnect the ventilator and contact your authorized VIASYS Healthcare
service technician.

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30 Bear Cub 750PSV

Table 3-1: Standard Settings

Mode SIMV

Rate 30 BPM

Inspiratory Pressure 40 cmH2O

Inspiratory Flow 15 L/min

PEEP/CPAP 0 cmH2O

Inspiratory Time 0.8 seconds

Base Flow 5 L/min

Assist Sensitivity MAX

O2% 21%

Apnea 10 seconds

Low PEEP/CPAP Alarm -3 cmH2O

Volume Limit™ 300 ml

High Pressure Limit 50 cmH2O

Low Inspiratory Pressure Alarm 30 cmH2O

High Breath Rate Alarm 40 BPM

Table 3-2: Rate

Set Rate Inspiratory Time Using stop watch verify Breath Rate

10 BPM 3 seconds 10 ± 2 BPM

40 BPM 1 second 40 ± 3 BPM

80 BPM 0.4 seconds 80 ± 4 BPM

120 BPM 0.1 seconds 120 ± 6 BPM

Table 3-3: Exhalation Time and I/E Ratio Table

Rate Set Inspiratory time Verify Exhalation

Time

10 BPM 3.00 seconds 3.0 ± 0.4 sec 1:1.0 ± 0.3

75 BPM 0.40 seconds - - - - - - - - 1:1.0 ± 0.3

Verify I/E Ratio

150 BPM 0.10 seconds - - - - - - - - 1:3.0 ± 0.4

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Service Manual 31

WARNINGS

The following warnings must be read and understood before performing the
procedures described in this section.

• Under no circumstances should this medical device be operated in the presence

of flammable anesthetics or other volatile materials due to a possible explosion
hazard.

• Liquid spilled or dripped into the unit may cause damage to the unit or result in

an electrical shock hazard.

• Oxygen vigorously accelerates combustion. To avoid violent ignition, do not use

any gauges, valves, or other equipment that has been exposed to oil or grease
contamination.

• Do not release this medical device if any alarm/alert function is inoperative. To do

so could result in a malfunction without warning, possibly resulting in personal
injury, including death or property damage. Refer the unit to a Allied Healthcare
Authorized Service Technician or a Allied Healthcare Trained Hospital Service
Technician.

• All tubing and fittings used to connect high pressure gas (air and oxygen) from

the source to the test equipment and from the test equipment to the device being
tested must be capable of withstanding a minimum supply pressure of 100 psi
(7.03 kg/cm2). The use of tubing and fittings not capable of withstanding this
pressure could cause the tubing to rupture, resulting in personal injury or
property damage.

• When verifying the operation of this medical device, do not breathe directly from

the machine. Always use a fresh bacterial filter and test circuit. A hazard to the
health of the service person may result.

• If any of the following procedures cannot be verified as outlined in this document,

do not use this device on a patient and refer it to Allied Healthcare or a Allied
Healthcare Authorized Service Facility or a Allied Healthcare Trained Hospital
Service Technician.

CAUTIONS

• Do not sterilize the ventilator. The internal materials are not compatible with

sterilization techniques.

• Do not use MEK or Trichloroethylene, as damage to surface may result. Do not

allow any liquid to spill or drip into the ventilator.

• Circuit boards are subject to damage by static electricity. Do not touch

components, circuit, or connector fingers with hands. Handle only by edges.

Before using any test equipment [electronic or pneumatic] for calibration procedures
[other than operational verification], the accuracy of the instruments must be verified
by a testing laboratory. The laboratory master test instruments must be traceable to
the NIST (National Institute of Standards Technology) or equivalent. When variances
exist between the indicated and actual values, the calibration curves [provided for
each instrument by the testing laboratory] must be used to establish the actual

L2342 Revision B November 2004

32 Bear Cub 750PSV

correct values. This certification procedure should be performed at least once every
six months. More frequent certification may be required based on usage and…..???

Test Procedures

1. Set up the ventilator with a standard infant test circuit. Plug the end of circuit
with rubber stopper.

2. Set the ventilator to standard settings per Table A. Ensure overpressure relief
valve is set to maximum pressure. Connect air, oxygen, and AC power to
ventilator.

3. Press the TEST button, verify all indicators and digits illuminate.

4. Verify rates per Table B. While doing rate verification you will get a rate alarm.
Press the alarm silence button. Verify that the audible alarm is silenced and
the silence is canceled after 60 seconds ± 10%. Return to standard settings.
Set mode to Assist Control.

5. Verify Exhalation Time and I:E Ratio per Table C. Return to standard settings.

6. Adjust Inspiratory Pressure to 25 cmH
alarm.

7. Increase Inspiratory Pressure to 50 cmH
limit.

8. Return Inspiratory Pressure to 40 cmH
verify that the Low Pressure and High Pressure LEDs are canceled.

9. Occlude patient circuit limb going to the exhalation valve. Verify that a
prolonged inspiratory alarm occurs.

10. Increase ventilator rate to 45 BPM. Verify that the High Rate alarm activates.

11. Decrease rate to 4 BPM. Verify that the apnea alarm activates.

12. Set ventilator rate to 70 BPM. Verify that the Incompatible Setting alarm
activates. Return rate to 30 BPM.

13. Push the Pressure Selector button to read air pressure. Verify reading is within
5 PSI of input pressure.

14. Push the Pressure Selector button to read O
within 5 PSI of O

supply pressure.

2

15. Disconnect air supply. Verify that the Low Gas Supply alarm activates.
Reconnect air supply.

16. Disconnect O

supply. Verify that the Low Gas Supply alarm activates.

2

17. Disconnect the air supply. Verify that the fail to cycle alarm activates.
Reconnect the air and O

18. Connect an O

analyzer inline. Verify that the FIO2 is within ± 3% at the

2

supplies.

2

following settings: 21%, 60%, 100%. Remove O

19. Adjust the rate to 10 BPM. Turn the Low PEEP/CPAP alarm to 5 cmH
Verify that the Low PEEP/CPAP alarm activates. Return the Low PEEP/CPAP
alarm to -3 cmH

O.

2

20. Disconnect the AC power. Verify that the audible alarm activates and the line
power LED illuminates red within 10 seconds. Push the Visual Reset button.

O. Verify activation of Low Pressure

2

O. Verify High Pressure alarm and

2

O. Push the Visual Reset button and

2

Pressure. Verify reading is

2

analyzer.

2

O.

2

L2342 Revision B November 2004

Service Manual 33

Verify that the audible alarm is canceled and the unit continues to function.
Reconnect the AC power.

21. Connect the circuit to the infant test lung. Set the Volume Limit to 25ml. Verify
That the tidal Volume readout is 25 ml ± 20%.

22. Disconnect the Flow Sensor cable from the ventilator. Verify that the flow
sensor alarm activates, assist sensitivity window is blank, and that the
monitored volume and volume limit displays show dashes. Reconnect the flow
sensor cable, verify audible alarm cancels, assist sensitivity window
illuminates, and volume digits return.

23. Turn Assist Sensitivity to MIN. Squeeze and release the patient circuit. Verify
that the unit will assist and that Patient Initiated LED is illuminating.

24. Disconnect the patient circuit from the test lung. Verify that both audible and
visual Low Inspiratory Pressure alarms are activated. Verify that the Alarm
Loudness can be varied from minimum to maximum, but the alarm cannot be
turned off.

Figure 3-1: Bear Cub 750 US with Patient Circuit

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34 Bear Cub 750PSV

Exterior Inspection and Cleaning

Inspect all cords, connectors, and fittings. Inspect the case for any cracks or other
damage.

Exterior Cleaning

1. Before any cleaning of the ventilator, disconnect WALL AC.

2. Clean the exterior of the ventilator with an appropriate bactericidal or
germicidal agent. Care should be exercised not to allow any liquid to penetrate
the inside of the ventilator.

CAUTION

Do not use Methyl Ethyl Ketone (MEK) or Tricloroethylene, as damage to surfaces
will result. Do not allow any liquid to spill or drip into the ventilator.

Plugs and Cables

Plugs and cables may be wiped down with an appropriate bactericidal or germicidal
agent.

L2342 Revision B November 2004

Service Manual 35

OVP Checklist

This checklist is for use during the BEAR CUB™ 750vs Operational Verification Procedure.
Serial Number
Service Location
Address
City/State/Zip
Contact
Phone ( )

Hour meter reading Today’s date

Service Organization
Address
City/State/Zip
Contact
Phone ( )

Verification Steps

STEP PASS FAIL STEP PASS FAIL

Indicator Verification O2 Pressure Reading

Verification

Breath Rate Verification Low Gas Supply

Verification(Air)

Alarm Silence, Reset Verification Low Gas Supply Verification

(O2)

Exhalation Time, I:E Ratio
Verification

Low Pressure alarm Verification FIO2 verification (21%, 60%,

High Pressure alarm/Limit
Verification

Pressure LED reset AC power loss verification

Prolonged Inspiratory alarm
verification

High Rate alarm verification Flow Sensor alarm

Apnea alarm verification Patient Triggering verification

Incompatible setting alarm
verification

Fail to Cycle alarm

verification

100%)

Low PEEP/CPAP alarm

verification

Tidal Volume Limit

verification

verification

Alarm loudness verification

Air Pressure reading verification

ADD Warning ?????

Signature _________________________________________

PROCEDURE COMPLETE

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Service Manual 37

Chapter 4 Calibration
(for software releases 2 and 3 only)

Introduction

The information in this section is intended for use by a factory trained service
technician. Before opening the console or removing assemblies to perform
calibration, a reference should be made to the Instruction Manual and Sections 1, 2,
3, and 7 of this Manual to assure that the ventilator is being properly utilized.

WARNINGS

• The calibration procedures contained in this section must be completed when
any part/assembly has been removed and/or replaced. Failure to do so could
result in ventilator malfunction and injury or death to the patient.

• After calibration and/or replacement of any assembly(ies), always perform the
Operational Verification Procedure (Section 3), then allow a "BURN-IN" period
and repeat the Operational Verification Procedure.

• Oxygen vigorously accelerates combustion. DO NOT use any gauges, valves or
other equipment that has been exposed to oil or grease contamination to avoid
violent ignition.

• Hazardous voltages exist within the ventilator. Always observe appropriate
safety precautions when working on the ventilator while the machine is
connected to an electrical power source to prevent possible accidental injurious
electrical shock.

• When high pressure gas sources are connected to the ventilator, always use
extreme caution when attempting to measure internal pressures. Abnormal
conditions may exist where measured pressures exceed the burst pressure of
the gauge, resulting in possible injury.

NOTE

The Operational Verification Procedure (OVP) is always performed prior to use of
this section.

CAUTION

• Before using any test equipment (electronic or pneumatic) for calibration
purposes (other than operational verification), the accuracy of the instruments
must be certified by a testing laboratory. The laboratory master test instruments
must be traceable to the US Bureau of Standards or equivalent. When variances
exist between the indicated and actual values, the calibration curves (proved by
the testing laboratory) must be used to establish the actual correct values. This
certification procedure should be performed at least once every six months. More
frequent certification may be required based on usage and environment.

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38 Bear Cub 750PSV

NOTE

If problems are incurred in obtaining the calibration performance, refer to
Troubleshooting (Section 7) or contact your dealer or VIASYS Healthcare Service
Facility.

Pressure Transducers and Flow Control Valve Calibration

Turn OFF the ventilator and disconnect tubing to the Pressure Transducers on the
Control PCB. Press and hold the diagnostic switch on the Control PCB while turning
the ventilator ON to enter Transducers and Flow Calibration routines. Throughout
calibration, the TEST key is for advancing the calibration number; VISUAL RESET is
for backing to previous calibration, and the MANUAL BREATH key is for recording
calibration data. The calibration number and message are displayed in the Breath
Rate and Monitored Time/I:E Ratio windows respectively. Data (when applicable) is
displayed in the Monitored Pressure window. Refer to the following (See table 4-1)
to calibrate the transducers on the Control PCB:

Table 4-1: Control PCB Transducer Calibration

Transducer Calibration Number Message Input Static Pressure
Machine (port B) d00 nP00 0 cmH2O

d01 nP40 40 ± 0.2 cmH2O
Differential (port B) d02 dP00 0 cmH2O

d03 dP40 40 ± 0.2 cmH2O
Proximal (port B) d04 pP00 0 cmH2O

d05 pP40 40 ± 0.2 cmH2O
O2 (A2) d06 0P00 0 PSIG

d07 0P40 40 ± 0.2 PSIG
AIR (A1) d08 AP00 0 PSIG

d09 AP40 40 ± 0.2 PSIG

NOTE

The 40 cm/psi settings were 70 cm/psi prior to monitor firmware 511-02803-00.
When calibrating the pressure transducers, both pressure points (i.e. 0 and 40
cm/psi) must be read and the 0 cm/psi reading must be obtained first.

1. Check the accuracy of the five pressure transducers per table 4.2. The
window shows the pressure readings monitor pressure.

2. Press the TEST key to advance the calibration number to the Display Set
Altitude Test, then press the MANUAL BREATH key until the number in the
PRESSURE window indicates the altitude at which the Flow Control valve
calibration is to be performed (expressed in units of 100 ft). Then advance to
the next test number and power down.

3. Re-connect tubing to the transducers on the Control PCB; apply Air and O2
(approximately 50 psi) to UUT. Use an RT-200 to measure flow at the TO

L2342 Revision B November 2004

Service Manual 39

PATIENT port. To calibrate the Flow Control Valve, press the TEST key to
advance the calibration number; then set flow as specified and press the
MANUAL BREATH key to record data. Calibrate Base Flow, then Calibrate
Inspiratory Flow.

Table 4-2: Calibration

Transducer Calibration Number Message Input Static Pressure
Differential (port B) d10 0 ± 1 0 cmH2O

d10 50 ± 1 50 ± 0.5 cmH2O
Machine (port B) d11 0 ± 1 0 cmH2O

d11 50 ± 1 50 ± 0.5 cmH2O
Proximal (port B) d12 0 ± 1 0 cmH2O

d12 50 ± 1 50 ± 0.5 cmH2O
AIR (A1) d13 50 ± 2 50 ± 0.2 PSI
O2 (A2) d14 50 ± 2 50 ± 0.2 PSI

NOTE

The pressure display occasionally flickering 1 digit beyond the tolerance is
acceptable.

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40 Bear Cub 750PSV

Table 4-3: Diagnostic Function

NUMBER FUNCTION

00 Calibrate pmach @ 0 cmH2O

01 Calibrate pmach @ 40 cmH2O

02 Calibrate pdelta @ 0 cmH2O

03 Calibrate pdelta @ 40 cmH2O

04 Calibrate proxp @ 0 cmH2O

05 Calibrate proxp @ 40 cmH2O

06 Calibrate O2p @ 0 cmH2O

07 Calibrate O2p @ 40 cmH2O

08 Calibrate airp @ 0 cmH2O

09 Calibrate airp @ 40 cmH2O

10 Display pdelta

11 Display pmach

12 Display proxp

13 Display airp

14 Display O2p

15 Display/Set Altitude

16 Calibrate Base Flow @ 1 L/min*

17 Calibrate Base Flow @ 2 L/min*

18 Calibrate Base Flow @ 5 L/min*

19 Calibrate Base Flow @ 15 L/min*

20 Calibrate Base Flow @ 25 L/min*

21 Calibrate Base Flow @ 30 L/min*

22 Calibrate Insp Flow @ 1 L/min*

23 Calibrate Insp Flow @ 2 L/min*

24 Calibrate Insp Flow @ 5 L/min*

25 Calibrate Insp Flow @ 15 L/min*

26 Calibrate Insp Flow @ 25 L/min*

27 Calibrate Insp Flow @ 30 L/min*

*±0.5 L/min

NOTE

Diagnostic numbers can only be accessed by depressing the diagnostic switch on
the Control PCB while turning the Ventilator ON.

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Service Manual 41

Table 4-4: Inspiratory Flow Calibration

Flow Flow Flow Flow Flow Flow Flow Flow Flow

Sea Level 500 feet 1000 feet 1500 feet 2000 feet 2500 feet 3000 feet 3500 feet 4000 feet

2.00± .02 2.02± .02 2.04± .02 2.05± .02 2.08± .02 2.10± .02 2.12± .02 2.14± .02 2.16± .02

5.00± .03 5.05± .03 5.10± .03 5.14± .03 5.19± .03 5.24± .03 5.29± .03 5.33± .03 5.38± .03

15.00± .1 15.1± .1 15.3± .1 15.4± .1 15.5± .1 15.7± .1 15.8± .1 15.9± .1 16.1± .1

25.00± .2 25.2± .2 25.4± .2 25.6± .2 25.8± .2 26.0± .2 26.2± .2 26.4± .2 26.6± .2

30.00± .2 30.2± .2 30.5± .2 30.7± .2 30.9± .2 31.2± .2 31.4± .2 31.6± .2 31.9± .2

Flow Flow Flow Flow Flow Flow Flow Flow Flow
Sea Level 4500 feet 5000 feet 5500 feet 6000 feet 6500 feet 7000 feet 7500 feet 8000 feet

2.00± .02 2.18± .02 2.20± .02 2.23± .02 2.26± .02 2.29± .02 2.31± .02 2.34± .02 2.37± .02

5.00± .03 5.44± .03 5.5± .1 5.6± .1 5.6± .1 5.7± .1 5.8± .1 5.8± .1 5.9± .1

15.00± .1 16.2± .1 16.4± .1 16.6± .1 16.7± .1 16.9± .1 17.1± .1 17.3± .1 17.5± .1

25.00± .2 26.9± .2 27.1± .2 27.4± .2 27.7± .2 28.0± .2 28.3± .2 28.6± .2 28.9± .2

30.00± .2 32.1± .2 32.4± .2 32.7± .2 33.0± .2 33.4± .2 33.8± .2 34.1± .2 34.5± .2

Air and O2 Regulator Balance

Objective

To define the calibration requirements for balancing the Air and O2 Regulators.

Equipment

Pressure gauge, 0 - 30 psig, ± 1/4% F.S.

Differential pressure gauge, 2 - 0 - 2 cmH
3% F.S.

Requirements

Regulator and Bleed Valve Adjustment:

Set up per Standard Test Settings except set MODE to STANDBY

Set O

Set O

Patient circuit may be omitted

Blender as noted (Table 4-5)

2

supply pressure to 50 psi

2

O, ± 5% F.S. Flow meter, 0 - 10 L/min, ±

2

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42 Bear Cub 750PSV

Table 4-5: Regulator Balance

O

Blender

Component

Air Regulator 100% 17.0 ± 1 psig

O2 Regulator 60%

Bleed Valve 60%

Air Regulator 60%

O2 Regulator

Bleed Valve

2

Setting

Requirement

Adjust O

regulator to obtain a

2

pressure balance with the air
regulator within 2 cmH

2

O.
With Base Flow Control Valve
set to minimum, Bleed Valve
exhaust shall equal 3.5 - 5.5
L/min.
Increase Base Flow rate to
maximum.
Regulators shall remain
balanced within 2 cmH

2

O.
Bleed Valve Flow drops to less
than .25 L/min.

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Service Manual 43

Table 4-6: Standard Test Settings

CONTROLS

Mode Assist/Control

PEEP/CPAP Pressure 0 cmH2O

Inspiratory Pressure (PIP) 20 cmH2O

Ventilator Rate 30 BPM

Inspiratory Time 1.00 second

Volume Limit 300 mL

Base Flow 5 L/min

Inspiratory Flow 15 L/min

Assist Sensitivity Mid Range

ALARMS

Low PEEP/CPAP Alarm -5 cmH2O

High Breath Rate Alarm 255 BPM

Low Inspiratory Pressure Alarm 5 cmH2O

High Pressure Limit Alarm 75 cmH2O

FRONT OF VENTILATOR

Humidifier VH-820 chamber, no water

Patient Circuit Standard Allied Infant Circuit

Patient Resistance Rp 20

Patient Compliance C3

Endotracheal Tube None

Auxiliary Pressure Relief Fully closed (CW)

REAR OF VENTILATOR

Alarm Loudness Control Minimum

RS-232 Interface Open

Analog Output Open

Remote Nurses call Open

APNEA Alarm 30 seconds

Display Power Outlet Open

AC Line Voltage 120 VAC

O2 Supply >35 PSI

Air Supply >35 PSI

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Service Manual 45

Chapter 5 Schematics and Assemblies

Figu

re 5-1:

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Figure 5-2:

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Figure 5-3:

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48 Bear Cub 750PSV

Figure 5-4:

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Figure 5-5:

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Figure 5-6:

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Figure 5-7:

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Figure 5-8:

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Figure 5-9:

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Figure 5-10:

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Figure 5-11:

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Figure 5-12:

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Figure 5-13:

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Figure 5-14:

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Figure 5-15:

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Figure 5-16:

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Figure 5-17:

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62 Bear Cub 750PSV

Figure 5-18:

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Figure 5-19:

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64 Bear Cub 750PSV

Figure 5-20:

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Figure 5-21:

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66 Bear Cub 750PSV

Figure 5-22:

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Figure 5-23:

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68 Bear Cub 750PSV

51-09640-XX Rev E
SHEET 2 OF 6

Figure 5-24:

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Figure 5-25:

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70 Bear Cub 750PSV

51-09640-XX Rev E
SHEET 4 OF 6

Figure 5-26:

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Figure 5-27:

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72 Bear Cub 750PSV

Figure 5-28:

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Figure 5-29:

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Figure 5-30:

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Figure 5-31:

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76 Bear Cub 750PSV

54805-1906 Rev A
SHEET 4 OF 4

Figure 5-32:

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Figure 5-33:

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78 Bear Cub 750PSV

Figure 5-34:

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Figure 5-35

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Service Manual 81

Chapter 6 Troubleshooting

Figure 6-1: Troubleshotting Decision Tree

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82 Bear Cub 750PSV

A

p

Table 6-2: Troubleshooting

Symptom Possible Causes Corrective Action

Failed To Cycle
Alarm

Low PEEP/CPAP
and Low Inspiratory
Pressure Alarms
Faulty or Out of
Specification.
Pressure Limit
Control Does Not
Function Correctly.
Pressure Limit Not
Within
Specifications.
No Delivered
Inspiratory Flow.

Base and/or
Inspiratory Digital
Flow Readings Do
Not Agree With
Actual Measured
Flow.
PEEP/CPAP Levels
Will Not Adjust.
Oxygen
Percentages Are Not
Within Specification.

1. Air and Oxygen
Pressure Have
Decreased Below 24 ± 2
PSIG.

2. Power Supply Failure.

3. System Supply Failure.

4. System Software
Failure.

1. Calibration Pressure
Transducer.

2. Defective Pressure
Transducer.

1. Calibration Pressure
Transducer.

2. Defective Control PCB.

3. Defective Pressure Limit
Valve.

1. Defective Flow Control
Solenoid Valve.

2. Defective Control PCB.

1. Flow Valve Calibration. 1. Perform Flow Valve Calibration Per

1. Defective PEEP Valve. 1. Remove and Replace PEEP Valve

1. Air/O2 Differential
Pressure Greater Than ±
2 CmH

2.

O.

2

ir and/or O

2

1. Verify Inlet Air and O2 Pressure
Entering The Ventilator. Verify
Calibration of Air and Pressure
Transducers On Control PCB.

2. Verify Power Supply Voltages At
The 15 Pin Header Connection
Labeled Tp1 On The Control PCB
Per The Table Below. If Out of
Specification, Replace Power
Supply.

Voltage Test Pt Ground Pt

+5.0 VDC TP1-1 T1P-13
± 5% (4.75-5.25) VDC
+7.0 VDC TP1-6 TP1-7
± 5% (6.65-7.35) VDC
+10.0 VDC TP1-8 TP1-9
± 5% (9.5-10.5) VDC

-10.0 VDC TP1-10 TP1-9

± 5% (10.5) VDC

-15% (8.5) VDC

3. Remove and Replace Control PCB.

4. Remove and Replace System
EEPROM (U-18 On Control PCB)

1. Calibrate Pressure Transducer Per
Section 5 of This Manual.

2. Remove and Replace Control PCB.

1. Calibrate Pressure Transducer Per
Section 5 of This Manual.

2. Remove and Replace Control PCB.

3. Remove and Replace Pressure
Valve.

1. Remove and Replace Flow Control
Valve Assembly

2. Remove and Replace Control PCB.

Section 5 of This Manual.

Assembly.

1. Perform Differential Pressure
Calibration Per Section 5 of This
Manual.

2. Re

lace Air and/or Oxygen

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Service Manual 83

p

Symptom Possible Causes Corrective Action

Regulator(S) Defective.

3. Defective Oxygen
Blender.

4. Defective Cross-Over
Check Valve.

Front Panel
Control(S) Will Not
Adjust.
Base and Inspiratory
Flow Cycles But No
Pressure Building
During Inspiration.
No Flow Out of TO
PATIENT Outlet.
Pressure Settings
Incompatible Alarm.

Ventilator Will Not
Turn On.

Audible Alarm Does
Not Activate.

Flow Sensor Alarm. 1. Flow Sensor Not

"Settings
Incompatible" Alarm;
E.Fl. or E.Pl
Flashing.
Inspiratory Pressure
Too Low.

1. Defective Front Panel
Potentiometer(S).

1. Defective Dump
Solenoid Valve.

2. Defective Control PCB.

3. Adjustable Overpressure
Relief Valve Setting.

1. Inspiratory Pressure

Level Set Below
Peep/Cpap Level.

2. Control PCB Has Lost

Calibration Data.

3. Defective Control PCB.

1. Internal Battery Not
Connected.

2. Internal Battery
Discharged Below
Minimum Operating
Voltage.

3. Internal Battery
Defective.

4. Ventilator Not Plugged
In To Wall Ac Power.

1. Wiring Connection.

2. Defective Alarm
Speaker.

3. Defective Control Pcb.

Connected.

2. Flow Sensor Not
Installed In Patient
Circuit.

3. Occluded Flow Sensor
and/or Endotracheal
Tube.

4. Defective Flow Sensor.

1. Incompatible Volume
Limit Setting.

1. Control Pin In Exhalation
Valve Sticking.

2. Defective Exhalation
Valve Diaphragm.

3. Defective Exhalation

Regulator.

3. Replace Oxygen Blender.

4. Replace Defective Check Valve.

1. Remove and Replace Display PCB.

1. Remove and Replace Dump
Solenoid Valve.

2. Remove and Replace Control PCB.

3. Evaluate/Adjust Valve Setting.

1. Evaluate Pressure Limit and

PEEP/CPAP Level Settings.

2. Calibration Control PCB Per Section

5 of This Manual.

3. Remove and Replace Control PCB.

1. Connect Internal Battery.

2. Re-Charge Internal Battery Connect
Ventilator Power Cord To A Wall AC
Outlet.

3. Remove and Replace Internal
Battery.

4. Connect Ventilator Power Cord To
A Wall AC Outlet.

1. Verify Connection of P1 of Audible
Alarm Cable To J1 of Controller
Pcb.

2. Remove and Replace Alarm
Speaker Sub-Assembly.

3. Remove and Replace Control Pcb.

1. Connect Flow Sensor To Both
Ventilator Connector and 4 Way
Patient Connector.

2. Install Flow Sensor.

3. Remove Occlusion.

4. Remove and Replace Flow

Sensor.

1. Evaluate Volume Limit Setting
Versus Flow and Pressure Limit
Settings.

1. Clean Control Pin. Verify Freedom
of Movement.

2. Remove and Replace Exhalation
Valve Diagram.

3. Remove and Re

lace Exhalation

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84 Bear Cub 750PSV

Symptom Possible Causes Corrective Action

Valve.

4. Adjustable Overpressure
Relief Valve Setting.

5. Adjustable Overpressure
Relief Valve Leaking
(With 1 L/Min Flow
Setting).

Valve.

4. Evaluate/Adjust Valve Setting.

5. Remove and Replace Aopr Valve.

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Service Manual 85

Chapter 7 Removal & Replacement

WARNIINGS

• Disconnect all electrical power, air, and oxygen sources before attempting
any disassembly. Failure to do so could result in injury to the service
technician or damage to equipment.

• After replacement of any assembly(ies), always repeat the Operational
Verification Procedure (refer to chapter 3), then allow a "burn-in" period and
repeat the Operational Verification Procedure.

Interior Access

1. If connected, remove cables leading to RS-232 and Analog outputs ports of the
ventilator.

2. Remove the seven screws indicated in Figure 8-1.

3. Slide the cover off of the unit applying slight pressure to the outside bottom
portion of the cover.

4. Remove the two screws indicated in Figure 8-2. The standoff tubes will drop
free when the screws are removed.

NOTE

The front portion will swing forward freely when the screws are removed. Take care
to ensure that the front swings slowly to avoid damage to the unit.

5. The front portion of the unit will drop forward, stopping when the end of the
retaining cord is reached. See Figure 8-3.

Flow Valve Assembly Removal

1. Disconnect hoses and connectors to the assembly.

2. Remove the four screws from the flow valve bracket, indicated in Figure 8-4.

3. Remove the Flow Valve Assembly from the unit.

4. To install, reverse removal procedure.

Control PCB Removal

1. Disconnect all hoses and connectors from the board.

2. Remove screw shown in Figure 8-5.

3. Lift board carefully from four retainer points.

4. Remove board from unit.

5. To install, reverse removal procedure.

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86 Bear Cub 750PSV

Display PCB Removal

1. Remove control PCB . See Control PCB Removal Figure 8-5.

2. Remove five screws shown in Figure 8-6.

3. Disconnect ground wire.

4. Remove board from unit.

5. To install, reverse removal procedure.

Air/O2 Regulator Removal

1. Remove Air/O2 fittings from the rear of the ventilator. See Figure 8-7.

2. Remove all hoses necessary to free the regulator assembly.

3. Remove three screws on rear panel.

4. Remove assembly from ventilator. See Figure 8-8

Blender Removal

1. Remove all hoses and wiring connected to the blender.

2. Loosen allen screws of knob located on the front of the ventilator. Remove
knob. See Figure 8-9.

3. Remove three screws located behind the knob. See Figures 8-10 and 8-11

4. Remove blender from unit.

5. To install, reverse order of removal.

Exhalation Valve Removal

1. Remove all hoses and wiring connected to the valve.

2. Remove three screws located on mounting plate. See Figure 8-12.

3. Remove Exhalation Valve from the ventilator.

4. To install, reverse removal procedure.

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Service Manual 87

Chapter 8 Preventive Maintenance

Replacement Parts

50000-13040 PM Kit contains the following parts:

Air Inlet Disc Filter (1) 52000-00551

O-ring (1) 53021-01012

O2 Inlet Disc Filter (1) 52000-00552

O-ring (1) 53021-01011

Prox Line Filter (1) 51000-01122

Flow Valve Input Filter (1) 52000-01187

Flow Solenoid Pilot Filter (1) 52000-02097

Air Regulator (1) 52000-00129

Install the following parts using this document and related documents mentioned.
Perform Calibration Verification Procedure and Operational Verification Procedure as
described.

Recommended Service Procedure

Preventive Maintenance on the BEAR CUB™ 750vs Infant Ventilator should be
completed at least once per year. Maintenance is intended to be done in the hospital
by a Bear Medical Products Authorized Service Technician or a Bear Medical
Products Trained Hospital Service Technician.

Ventilator Preventive Maintenance includes:

• Visually inspecting and cleaning of external surfaces, controls, attachments
and accessories.

• Opening and cleaning the interior of the unit.

• Visually inspecting all tubing, electrical wiring, connectors, and crimps,

screws, nuts and hardware. Checking the general condition of all other
internal components or assemblies.

• Replacing the Air and O

• Replacing the Air and O

• Pneumatic and electronic verification and calibrating if required.

• Performing the Operational Verification Procedure.

filters.

2

inlet bowls and seals.

2

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88 Bear Cub 750PSV

CAUTION

Before using any test equipment (Electronic or Pneumatic) for calibration procedures
(other than Operational Verification), the accuracy of the instruments must be
certified by a testing laboratory. The laboratory master test instruments must be
traceable to the U.S. Bureau of Standards or Equivalent. When variances exist
between indication and actual values, the calibration curves provided for each
instrument by the testing laboratory must be used to establish the actual correct
values. This certification should be performed at least once every six months. More
frequent certification may be required based on usage and environment.

Exterior Inspection

1. Turn off the ventilator and disconnect from AC power and pressurized gas at
the wall sources.

2. Clean the exterior of the unit with water or a solution of 70% Isopropyl Alcohol
solution only. Wipe all surfaces with a soft cloth or disposable wipe moistened
in the cleaning solution.

3. Inspect the exterior surfaces of the ventilator for broken or loose knobs. Check
the display panel for scratches, cracks and alignment of LED indicators.
Check all front and rear panel fittings, circuit breakers and accessories for
security. Check the AC electrical cord and plug for damage. Record the
reading of the hour meter on the maintenance check list.

4. Replace the ambient air intake filters at the rear of the ventilator.

CAUTION

Do not use Methyl Ethyl Ketone (MEK) or Tricloroethylene, as damage to surfaces
will result. Do not allow any liquid to spill or drip into the ventilator.

Interior Inspection

1. Open the Ventilator.

2. Vacuum all surfaces inside the ventilator. Be sure to reach areas around
connectors, circuits boards and pneumatic assemblies.

3. Visually inspect for any overheated components, loose connectors, damaged
wires or tubing, kinked tubing, loose ribbon cables, loose or missing hardware,
signs of water or other residue inside Tygon tubing, loose Tywraps, poor
connector crimps or loose fasteners.

Specifications

Current leakage – 100µA maximum (per UL 544)

Ground resistance – 0.1 ohms at 25.0 A (per UL 544)

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Service Manual 89

WARNING

When replacing Air/02 inlet filters, mark and remove one and only one fitting at
a time. Replace the filter and return the fitting to its original location before
removing the second fitting. Failure to follow this procedure may result in
injury, including death, to the patient.

Calibration and Verification Procedure

Perform Calibration and/or Calibration Verification Procedures as described in
chapter 4 of this manual.

CAUTION

Circuit boards are subject to damage by static electricity. Do not touch components,
circuit, or connector fingers with hands. Handle only by edges.

Ground Resistance Test

Perform a ground resistance check (follow manufacturer‘s instructions for test
equipment operation).

1. Connect a properly functioning leakage and grounding tester between the
ground connection and the hospital grade AC plug (middle lug) and the chassis
of the ventilator (any unpainted exposed metal part).

2. With the tester connected and operating, there should be no more than 0.10
ohms resistance between the plug ground connector, and the ventilator
chassis ground.

Current Leakage Test

Perform a current leakage test (always follow manufacturer‘s instructions for test
equipment operation).

1. Connect the ventilator to a properly functioning current leakage tester.

2. Turn Mode switch to CPAP and tester on.

3. Current leakage should be less than 100 microamps, grounded and
ungrounded.

Operational Verification Procedure

After Completing the Preventive Maintenance Procedure, perform the Operational
Verification Procedure (OVP) per Section 3, of this Manual. Ensure that the
ventilator is functioning properly. Complete an Operational Verification Procedure
Checklist form and attach it to the PM Checklist form. See the OVP for specific
instructions.

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Figure 8-1: Ventilator Back Panel

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Service Manual 91

BEAR CUB™ 750vs Infant VENTILATOR

PREVENTIVE MAINTENANCE CHECK LIST

Serial Number_____________ Hour meter reading_____________ Today's date ________

Service Location Service Organization

Address Address

City, State, Zip City, State, Zip

Contact Service Person

Phone (___) Phone (___)

VERIFICATION STEPS

Step Pass Fail Step Pass Fail

Inspection/Clean External Machine Transducer

Calibration

Inspection/Clean Interior Differential Transducer

Calibration

Replace Air/O2 Filter Proximal Transducer

Calibration

Replace O-ring O2 Transducer Calibration

Replace Prox Line Filter Air Transducer Calibration

Replace Flow Valve Filter Base Flow Calibration

Replace Solenoid Filter Inspiratory Flow

Calibration

Replace Air Regulator Verify FiO2

Air-O2 Regulator
Calibration

Complete OVP

WARNING

Do not release ventilator for use if it does not pass all of the procedures
specified in the checklist. To do so could result in personal injury including
death or property damage. Refer the ventilator to a Viasys Service Technician
or a Viasys trained Service technician for appropriate repair and/or calibration

Signature__________________________________

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Service Manual 93

Chapter 9 RS-232 Protocol

Scope

This document defines both the hardware and software protocol for the RS-232
communication port on the BEAR® 1000 Adult Ventilator, the BEAR CUB™ 750vs
Infant Ventilator, and the BEAR® Graphics Display. Throughout this document the
ventilator shall be defined as the SENDING device, that which transmits real time
data and responds to requests for data in the form of other parameters. This is true
even if the Graphic Display is in place acting as a repeater and providing data to a
third device.

Hardware Definition

Connector: Male 9-pin DSub connector (on the Ventilator).

Duplex: Full

Baud Rate: Selectable 1200, 2400, 9600, or 19200

Data: 8-bit character

1 Start bit, 1 Stop bit

No parity bit

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Pin Assignment

IBM standard 9-pin version of RS-232-C. The ventilator, is DTE and will interface to
any DCE device through a cable wired 1 to 1. (See table 9-1).

Table 9-1: Pin Assignment

DTE Name DTE Pin Direction DCE Pin Comment

DCD 1 <<- - - - - - - - 1 Not used by Ventilator

RxD 2 <<- - - - - - - - 2

TxD 3 - - - - - - - ->> 3

DTR 4 - - - - - - - ->> 4

GND 5 - - - - - - - - - - 5

DSR 6 <<- - - - - - - - 6 Not used by ventilator

RTS 7 - - - - - - - ->> 7 Tied High @ ventilator

CTS 8 <<- - - - - - - - 8

RI 9 <<- - - - - - - - 9 Not used by ventilator

Where: DCD=Data Carrier Detect DSR=Data set ready

RXD=Receive Data RTS=Request to send

T x D=Transmit Data CTS=Clear to send

DTR=Data Terminal Ready RI=Ring indicator

GND=GROUND

Alternatively, the ventilator can be interfaced to a DTE device with the following "null­modem" interface. (See table 9-2).

Table 9-2: Alternate Pin Assignment

DTE Name DTE Pin Direction DTE Pin DTE NAME

GND 5 - - - - - - - - - - 5 GND

RxD 2 <<- - - - - - - - 3 TXD

TxD 3 - - - - - - - ->> 2 RXD

RTS 7 - - - - - - - ->> 1 DCD

DTR 4 - - - - - - - ->> 6 & 8 DSR & CTS

RI 9 Not used 9 RI

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Service Manual 95

Software Protocol

The ventilator’s RS-232 port has two modes of communication. The first mode
continuously outputs real time data every 10 msec and will provide non-real time
data upon request from an external device. This mode requires 19.2 kBaud data
rate. This second mode will only provide non-real time data upon request from an
external device (all other data rates). The mode of communication is selected by the
user upon installation simultaneously with and as a function of the baud rate.

Continuous Output (Default Mode)

The continuous output mode communicates at 19.2 kBaud and sends out the real
time data (flow, pressure, breath phase, breath type, and alarm status) every 10
msec. Upon request, non-real time data will also be sent, however it may delay the
real time data by up to 25 msec. Note, the real time data is queued by the ventilator
so that it is only delayed and not lost.

Data Upon Request

All non-real time data, consisting of control settings, alarm settings and status, and
monitor values will be provided upon request from an external device. This data can
be requested at any transmitted baud rate. The buffer for requested data will be
limited, but will have the capability such that at least three (3) transactions (requests)
can be handled (queued) at a time. Any additional data requests prior to completion
of a corresponding number of message transmissions may be ignored by the
ventilator.

Data Format

The messages are sent and received in variable length data packets. All packets are
preceded by a SYN character, and terminated by a check sum.

The purpose of the SYN character is to enable the receiver to detect the start of a
message, therefore it is an illegal character within a data packet. If the binary value
of SYN (16h) or DLE (10h) appears in the data packet (including the Check Sum,
see below) an escape sequence will be used. The illegal character will be preceded
by the DLE character and 10h will be subtracted from its original value.

The second character in each packet (both transmitted and received) is defined as
the ID character. Valid ID characters are defined in tables 9-3, 9-4 and 9-5.

All other ID's are undefined at this time or are for internal use only. Any request for
data using an undefined ID will be responded to by either the transmission of
undefined data or will be ignored by the ventilator.

The Check Sum [Check] is defined as the one’s complement of the sum of all data
contained in the data packet excluding the “SYN” and “CHECK” characters.

L2342 Revision B November 2004

96 Bear Cub 750PSV

Table 9-3: Valid Requests Received by the Ventilator

Format:

[ SYN ] [ID] [Check]

[ SYN ]: 16h

[ ID ]: 20h Send all Adult Control Settings

40h Send all Adult Alarm Settings/Status

60h Send all Adult Monitored Data

A0h Send all Infant Control Settings

C0h Send all Infant Alarm Settings/Status

E0h Send all Infant Monitored Data

[ Check ]: Check Sum

Table 9-4: Valid Message Transmitted by the Ventilator

Format:

[ SYN ] [ID] [Data #1] [Data #n] [Check]

[ SYN ]: 16h

[ ID ]: 00h..0Fh Real Time Data, No Alarms

10h 1Fh Real Time Data, Alarm Condition

20h Adult Control Settings

40h Adult Alarm Settings

60h Adult Monitor Settings

A0h Infant Control Settings

C0h Infant Alarm Settings

E0h Infant Monitor Settings

[ Data #X ]: Binary Data

[Check[: Check Sum

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Service Manual 97

Table 9-5: Real Time Data

Mode: Continuously, every 10-msec
Length: 6 Bytes

Format:

[ SYN ] [ID] [Data #1] [Data #3] [Check]
[ ID ]: Bit 7 — 0
Bit 6 — 0
Bit 5 — 0
Bit 4 — X
Bit 3 — Y
Bit 2 — Y
Bit 1 — Y
Bit 0 — Z

Alarm Condition (x):

0 — No Alarm
1 — Alarm

Breath Type (yyy):

000 — Volume
001 — Spontaneous
010 — Pressure Control
011 — Pressure Support
100 — Time Cycled/Pressure Relief
101 — Reserved
110 — Reserved
111 — Reserved

Breath Phase (z):

0 — Inspiration
1 — Exhalation

[Data #1] [Data #2] [Data #3]:

xxxxxxxx xxxxxyyy yyyyyyyy
| | | |
MSB LSB\MSB LSB

x: Net Flow (Insp-Exhale) - 13 bits

Range: -300 to +300 lpm
Binary Scale: 1 bit = 0.1 lpm
Binary Range: 0 to 6000
Zero offset: 3000

y: Proximal Pressure - 11 bits

Range: -60 to +140 cmH2O
Binary Scale: 1 bit = 0.1 cmH2O
Binary Range: 0 to 2000
Zero offset: 600

Alarm Condition

Breath Type

Breath Phase

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Table 9-6: Adult Ventilator Control Settings

Mode: Upon Request
Length: 16 Bytes
Format:

[ SYN ] [ID] [Data #1] [Data #13] [Check]

[ ID ] : 20h
[ Data #1 ] Mode/Wave:

Bit 7 — x
Bit 6 — x
Bit 5 — x
Bit 4 — y
Bit 3 — y
Bit 2 — Reserved (0)
Bit 1 — Reserved (0)
Bit 0 — Reserved (0)

Mode :

000 — Assist Control
001 — SIMV/CPAP/PSV
010 — Pressure Control
011 — Reserved
: :
111 — Reserved

Wave:

00 — Square
01 — Sine
10 — Decelerating
11 — Reserved

[Data #2] Switches:
Bit 7 — 100% O2 (1=on, 0=off)
Bit 6 — Sigh On (1=on, 0=off)
Bit 5 — Pres Aug (1=on, 0=off)
Bit 4 — Nebulizer (1=on, 0=off)
Bit 3 — Reserved (0)
Bit 2 — Reserved (0)
Bit 1 — Reserved (0)
Bit 0 — Reserved (0)

[Data #n] Parameter Range Binary Scale Binary Range

[Data #3] Tidal Vol 0.03 - 2.00L 0.01 L 3 - 200
[Data #4] Rate 0-120 bpm 0.5 bpm 0 - 240
[Data #5] Peak Flow 5 - 150 lpm 1 lpm 5 - 150
[Data #6] Percent O2 21 - 100% O2 1% O2 21 - 100
[Data #7] Assist Sens 0.2 - 5.0 cmH2O 0.1 cmH2O 2 - 50
[Data #8] PSV/Insp Pres 0 - 80 cmH2O 1 cmH2O 0 - 80
[Data #9] Insp Pause 0.0 - 2.0 sec 0.1 sec 0 - 20
[Data #10] MMV 0 - 50 Liters 1 Liter 0 - 50
[Data #11] Insp Time 0.0 - 5.0 sec 0.1 sec 0 - 50
[Data #12] CC 0.0 - 7.5 ml/cmH2O 0.1 ml/cmH2O 0 - 75
[Data #13] Pres Slope -P9 to P9, -9 to 9 1 1 – 38

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Service Manual 99

Table 9-7: Adult Ventilator Alarm Settings / Status

Mode: Upon Request

Length: 14 Bytes

Format: [ SYN ] [ID] [Data #1] [Data #13] [Check]

[ ID ] : 40h

[ Data #1 ] Alarm Status Byte - 1

Bit 7 — High Min Vol (1=on, 0=off)
Bit 6 — Low Min Vol (1=on, 0=off)
Bit 5 — High Insp Pres (1=on, 0=off)
Bit 4 — Low Insp Pres (1=on, 0=off)
Bit 3 — High Base Pres (1=on, 0=off)
Bit 2 — Low Base Pres (1=on, 0=off)
Bit 1 — High Rate (1=on, 0=off)
Bit 0 — Low Rate (1=on, 0=off)

[ Data #2 ] Alarm Status Byte - 2
Bit 7 — I:E Limit (1=on, 0=off)
Bit 6 — Run Diagnostics (1=on, 0=off)
Bit 5 — Gas Fail (1=on, 0=off)
Bit 4 — Failed to Cycle (1=on, 0=off)
Bit 3 — Reserved (0)
Bit 2 — Reserved (0)
Bit 1 — Reserved (0)
Bit 0 — Alarm Silence (0)

[Data #n] Parameter Range Binary Scale Binary Range

[Data #3] High Min Vol 0 - 80 L 1 L 0 - 80
[Data #4] Low Min Vol 0 - 50 L 1 L 0 - 50
[Data #5] High Insp Pres 0 - 120 cmH2O 1 cmH2O 0 - 120
[Data #6] Low Insp Pres 3 - 99 cmH2O 1 cmH2O 3 - 99
[Data #7] High Base Pres 0 - 55 cmH2O 1 cmH2O 0 - 55
[Data #8] Low Base Pres 0 - 50 cmH2O 1 cmH2O 0 - 50
[Data #9] High Rate 0 - 155 bpm 1 bpm 0 - 155
[Data #10] Low Rate 3 - 99 bpm 1 bpm 3 - 99
[Data #11] I:E Override on/off n/a 1/0

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100 Bear Cub 750PSV

Table 9-8: Adult Ventilator Monitor Status

Mode: Upon Request

Length: 18 Bytes

Format:

[ SYN ] [ID] [Data #1] [Data #15] [Check]

[ ID ] : 60h

[ Data #1 ] Breath Data

Bit 7 — Control Breath (1=on, 0=off)
Bit 6 — Sigh Breath (1=on, 0=off)
Bit 5 — Patient Effort (1=on, 0=off)
Bit 4 — MMV Active (1=on, 0=off)
Bit 3 — Reserved (0)
Bit 2 — Reserved (0)
Bit 1 — Reserved (0)
Bit 0 — Reserved (0)

[Data #n] Parameter Range Binary Scale Binary Range

[Data #2] MSB Tidal Vol 0 - 9.99 L 0.01 L 0 - 999
[Data #3] LSB " "
[Data #4] MSB Minute Vol 0 - 99.9 L 0.1 L 0 - 999
[Data #5] LSB " "
[Data #6] MSB Spon Min Vol 0 - 99.9 L 0.1 L 0 - 999
[Data #7] LSB " "
[Data #8] MSB 1/I:E Ratio 0.00 - 4.0 0.01 0 - 400
[Data #9] LSB " "
[Data #10] Total Rate 0 - 155 bpm 1 bpm 0 - 155
[Data #11] Spon Rate 0 - 155 bpm 1 bpm 0 - 155
[Data #12] %MMV 0 - 100 %/hr 1 %/hr 0 - 100
[Data #13] Mean Pres 0 - 140 cmH2O 1 cmH2O 0 - 140
[Data #14] Peak Pres 0 - 140 cmH2O 1 cmH2O 0 - 140
[Data #15] Plateau Pres 0 - 140 cmH2O 1 cmH2O 0 – 140

L2342 Revision B November 2004