Respironics BiPAP Focus User manual

REF 1029568 Rev A
BiPAP®Focus™Ventilator
SERVICE MANUAL

II BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. REF 1029568 Rev A
Copyright © 2006. Respironics, Inc.
ALL RIGHTS RESERVED.
This work is protected under Title 17 of the United States copyright code and is the sole property of Respironics.
No part of this document may be copied or otherwise reproduced, or stored in any electronic information
retrieval system, except as specifically permitted under United States copyright law, without the prior written
consent of Respironics.
In the U.S. and Canada
Respironics California, Inc.
2271 Cosmos Court
Carlsbad, CA 92011
USA
1-800-345-6443
For Technical support, contact:
Respironics, Inc. Customer Service
Within the U.S.A. 1-800-345-6443
Outside the U.S.A. 724-387-4000
Facsimile 724-387-5012
[email protected]

REF 1029568 Rev A BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. III
Table of Contents
1. Introduction and Intended Use. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Recommended Tools and Test Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Where to Go for Help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2. Warnings and Cautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Cautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
3. Theory of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Back Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
Default Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
Settings: CPAP Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
Settings: S/T Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
Measured Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
Alarm Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
Nurse Call Station/Serial Communications Connector Pinout . . . . . . . . . . . . 3-10
Physical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
Triggers and Cycles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
Environmental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
Bacteria Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
Date of Manufacture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
Pneumatics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13
4. Periodic Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Storing the BiPAP Focus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Cleaning the Reusable Air Inlet Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Replacing the Air Inlet Filter(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Replacing the Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
5. Diagnostic Mode and Troubleshooting . . . . . . . . . . . . . . . . . . . . . . 5-1
Entering Diagnostic Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Product Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
System Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
Preferences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
Significant Event Log. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
Setting Up the Serial Interface for DRPT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5

IV BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. REF 1029568 Rev A
Table of Contents
Generating a Diagnostic Report (DRPT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Sensor Readings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11
System Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15
Significant Event Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
6. Ventilator Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Download Service Software to the Service PC . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Installing Communications Software on the Service PC . . . . . . . . . . . . . . . . . . . . 6-2
Starting the BiPAP Focus Wizard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
Downloading Controller Board Software to the Ventilator . . . . . . . . . . . . . . . . . . . 6-4
Downloading UI Software to the Ventilator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Reprogramming the BiPAP Focus Serial Number . . . . . . . . . . . . . . . . . . . . . . . 6-13
7. Performance Verification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
Required Test Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Preliminary Cleaning, Inspection, and Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3
Electrical Safety Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3
Alarm/LED Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4
BiPAP Focus System Run-in. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5
Equipment Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5
Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5
Real-time Clock Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6
Equipment Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6
Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6
If Real-Time Clock Calibration Fails . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8
MFTS Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8
Multi Function Test Station Set-up (MFTS) . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8
MFTS software setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-9
Unit Under Test setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-10
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-11
Field Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-17
Equipment Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-17
Recording Serial Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-17
Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-18
Performance Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-28
Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-28
Performance Verification Data Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-29
8. Component Removal/Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
Disconnecting Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4
Top Enclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4
VGA Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
User Interface Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10
Controller PCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-11
Valve Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-13
Blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-14

Table of Contents
REF 1029568 Rev A BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. V
Secondary Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-15
Primary Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-16
Main Body Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-16
Interconnect Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-17
9. BiPAP Focus Replacement Parts List . . . . . . . . . . . . . . . . . . . . . . . 9-1
Complete Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1
Exterior. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3
Exterior
(continued) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4
Front Panel/User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4
Ventilator Interior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-5
Communications Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6
Electronic Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7

VI BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. REF 1029568 Rev A
Table of Contents

REF 1029568 Rev A BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. 1-1
Chapter 1. Introduction and Intended Use
The BiPAP Focus Non-invasive Ventilator is a microprocessor-controlled,
electrically powered mechanical ventilator. The BiPAP® Focus™ Ventilator
System provides noninvasive ventilation for adult (over 30 kg or 66 lbs.)
patients for the treatment of respiratory insufficiency and distress, and
obstructive sleep apnea. The BiPAP Focus is appropriate for acute, sub-acute,
and intra-hospital transport settings.
The BiPAP Focus System is intended for use with nasal and full face masks.
The BiPAP Focus is not intended to be a life-support device.
The BiPAP Focus Ventilator meets or exceeds all applicable safety
requirements, consensus guidelines, US regulatory statutes, and international
regulatory standards for life support/mechanical ventilation devices.
Read this manual thoroughly prior to performing service or maintenance on the
BiPAP Focus Ventilator. This manual contains advanced troubleshooting,
calibration, and maintenance instructions for the BiPAP Focus. All
maintenance and repair work should be performed by qualified biomedical
technicians who have received appropriate training and authorization to
provide maintenance, repair, and service for the BiPAP Focus.
Review the operating instructions for the BiPAP Focus Ventilator before
running tests, checking operational readiness, or initiating patient use. These
instructions include important information about ventilator safety and
operation.
For additional information about accessories or related equipment, such as
humidifiers and remote alarm systems, refer to the appropriate instruction
manual prior to operating with the BiPAP Focus Ventilator.
The BiPAP Focus Operator’s Manual for the BiPAP Focus Ventilator lists all
applicable warnings and cautions. Review these notices thoroughly before
operating the ventilator.

Chapter 1
1-2 BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. REF 1029568 Rev A
Introduction and Intended Use
Recommended Tools
and Test Equipment Table 1-1 lists the recommended tools, test equipment, and materials required
to service and maintain the BiPAP Focus Ventilator.
Table 1-1: Recommended Test Equipment, Tools, and Materials
Description Manufacturer and Model
Test Equipment
Digital multimeter (DMM) accurate to three decimal
places
Local Supplier
Electrical safety analyzer Dale LT 5440 or equivalent
Pneumatic calibration analyzer capable of measuring
low pressure (cmH2O), flow rate (LPM), and volume
(liters)
Respironics P/N 1012598 or equivalent
Ventilator Accessories
Connector, plastic, 22mm OD Respironics P/N 1006242 or equivalent
Connector, 22-mm (quantity 2) Respironics P/N or equivalent
Flow Control Valve Respironics P/N 1006120
Pressure test adapter Respironics P/N 312710
Tee, plastic with silicone rubber coupling Respironics P/N C06260 or equivalent
Tee silicone (quantity 2) Respironics P/N 1006243 or equivalent
Hand Tools and Materials
Pliers Local supplier
#1 Phillips head screwdriver Local supplier
#2 flat head screwdriver Local supplier
#2 Phillips head screwdriver Local supplier
Cleaning Cloth Local supplier
Isopropyl Alcohol Local supplier
Metric hex key set (rounded ends), 1.5 to 4 mm Local supplier
Mild detergent or antiseptic wipes Local supplier
Needle nose pliers Local supplier
BiPAP Focus Communications Cable Kit
(USB & DB9)
Respironics P/N 1030010
PC or laptop (required for downloading software) Required: Windows XP operating
systems, serial comm port, and USB
port
Pen size flat head screwdriver Local supplier
Pen size Phillips head screwdriver Local supplier
Test lung, hard sided Respironics P/N 1021671 or local
supplier
Torque driver capable of 1 to 25 in.-lbs (N-m) Local supplier

Chapter 1
Introduction and Intended Use
REF 1029568 Rev A BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. 1-3
Where to Go for Help For Customer Service and Product Support contact:
Respironics, Inc.
USA telephone: [phone]
USA: 1-800-886-0245
International telephone: [phone]
International fax: [phone]
[email protected].
[e-mail].
www.respironics.com.

Chapter 1
1-4 BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. REF 1029568 Rev A
Introduction and Intended Use
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REF 1029568 Rev A BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. 2-1
Chapter 2. Warnings and Cautions
Warnings, Cautions, and Notes are used throughout this manual to
identify possible safety hazards, conditions that may result in
equipment or property damage, and important information that must be
considered when performing service and testing procedures on the
BiPAP Focus.
Warnings • To assure the safety of the service technician and the specified
performance of the device, Respironics recommends that only
technicians having prior training or experience servicing
ventilatory devices perform any repairs or adjustment to the BiPAP
Focus.
• Use only Respironics repair/service parts. Use of non-Respironics
parts may alter ventilator reliability resulting in damage. Use of
non-Respironics repair parts will affect the ventilator warranty.
Contact Customer Service at 1-800-345-6443 or 724-387-4000
for more information.
• High voltages are present in the AC/DC Power Supply, Power Cord
and VGA PCB. To avoid electrical shock, disconnect the power
cord before attempting any repairs on the device or cleaning.
• DO NOT immerse this device into any fluids or allow any liquid to
enter the cabinet or the filter intake.
• To avoid personal injury, always disconnect external AC and DC
power sources from the ventilator before servicing or cleaning.
• To avoid personal injury or the possibility of damage to the
ventilator, regularly inspect the power cord to ensure it is free from
defects and any obvious wear and is properly grounded.
• This device is not for life support.
WARNING: A condition that could cause injury to a patient, operator or technician if
the operating instructions in this manual are not followed correctly.
CAUTION: A condition that could cause damage to, or shorten the service life of,
the device.
NOTE: Important information concerning the construction or operation of the
device.

Chapter 2
2-2 BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. REF 1029568 Rev A
Warnings and Cautions
• Never troubleshoot while a patient is connected to the ventilator,
since normal operation is suspended.
• If the ventilator has been operating, the internal parts may be hot.
Use caution when accessing.
• To prevent disease transmission, use protective equipment when
handling contaminated bacteria filters or other patient
accessories. Follow manufacturers' labeling and institutional
guidelines for disposal of contaminated accessories.
• To avoid cross-contamination between the test equipment and
ventilator, always install a bacteria filter between the main outlet
and test device.
• Explosion hazard. Do not operate the ventilator in the presence of
flammable anesthetic agents.
• To avoid the risk of fire, use only Respironics-approved batteries.
All battery connections are keyed to ensure proper connection. Do
not attempt to connect a battery incorrectly. Only qualified
technicians should install the battery.
• Use only Respironics-supplied cables with the nurse call station/
serial communications connector.
• To avoid personal injury or the possibility of damage to the
ventilator, DO NOT operate this device if it has failed any of its
diagnostic tests, either self or service initiated.
Cautions • Federal law (US) restricts this device to sale by, or on the order of,
a physician.
• Failure to replace a dirty filter may cause the device to operate at
higher than normal temperatures and damage the device.
• Use only Respironics-approved filters.
• Use only Respironics-approved batteries.
• The gray reusable air inlet filter must be completely dry before
use. Never place a wet filter into the device.
• Do not place more than one gray reusable air inlet filters that
come with the ventilator into the device at the same time. One
gray reusable air inlet filter and one white disposable ultra-fine
filter may be used.
• Replace any filter that is damaged.
• Do not attempt to clean or reuse disposable air inlet filters.
• Electronic components used in this device are subject to damage
from static electricity. Repairs made to this device must be
performed only in an antistatic, Electro-static Discharge (ESD)-
protected environment.

Chapter 2
Warnings and Cautions
REF 1029568 Rev A BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. 2-3
• Care should be taken to avoid exposure of the BiPAP Focus to
temperatures at or near the extremes of those specified in Chapter
3. If exposure to such temperatures has occurred, the device
should be allowed to return to room temperature before being
turned on.
• Never place liquids on or near the BiPAP Focus.
• The information in this manual is provided for service personnel
reference.
• Always ensure that you are following proper electrostatic discharge
(ESD) grounding procedures before handling static-sensitive
devices.
• Be careful not to pull or crimp any cables, tubes or wires.
• Troubleshooting and repair should be performed only by a
qualified service technician.
Notes • Refer to the BiPAP Focus Operator’s Manual for product use,
additional Warnings, Cautions and Notes.

Chapter 2
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Warnings and Cautions
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REF 1029568 Rev A BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. 3-1
Chapter 3. Theory of Operation
The BiPAP® Focus™ Ventilator System provides noninvasive breathing
support for adult patients weighing 30 kg (66 lbs.) or greater.
The BiPAP Focus System offers two ventilation modes:
• Continuous positive airway pressure (CPAP), which provides a single
level of positive pressure to the patient.
• Spontaneous/Timed (S/T), which provides two levels of positive
pressure (one during inspiration and one during exhalation), and
delivers timed breaths if the patient does not initiate a breath.
The BiPAP Focus System alarms annunciate when high or low pressure
regulation, apnea, patient disconnect, low power, or loss of mains power
conditions occur. The system displays a real-time estimated delivered pressure
bar graph.
An Apnea Rate (#Apnea) Alarm is provided to alert the caregiver to repeated
periods of short apneas of 10 seconds or more. The caregiver can set the value
for how many apnea periods (10 seconds or more) can occur within an hour
before alarming. The total number of Apnea periods (10 seconds or more) for
the previous hour is displayed as part of the patient data. Because the previous
hours data is displayed, the number of apnea periods for the first hour is an
estimate only.
The BiPAP Focus System includes alarm silence and alarm pre-silence
features. Battery backup provides a minimum of 45 minutes of backup power
at default settings in case AC power is not available (for example, during
transport within the hospital).
The BiPAP Focus System features Digital Auto-Trak™, which allows it to
recognize and compensate for unintentional leaks and promote synchrony by
adjusting its trigger and cycle algorithms to maintain optimum performance.

Chapter 3
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Theory of Operation
Air Delivery System Components
Air Inlet Filter(s) The air inlet filter removes coarse particulate from
ambient air as it is entrained into the blower assembly.
See Section 4 for periodic maintenance information.
The BiPAP Focus has a reusable dust filter that is gray in
color. An optional pollen filter, white in color is also
available.
Blower The blower draws room air though the air inlet filter and
muffler, and outputs air for delivery to the patient. The
DC impeller-type blower recirculates air through the flow
valve when not delivering gas to the patient. Compressor
speed is determined by patient settings. The controller
PCB controls compressor speed.
Table 3-1: Air Delivery System Components

Chapter 3
Theory of Operation
REF 1029568 Rev A BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. 3-3
Flow valve (FV) The flow valve (valve assembly) is a mechanical sliding
assembly driven by an electromagnetic coil. Valve
commands from the PCB control current (-125mA to
675mA) to the coil. Movement of the flow valve is
proportional to the current through the coil. The flow
valve operates as a closed-loop system, using feedback
from the flow sensor and pressure transducers.
Air Flow Sensor The air flow sensor measures flow from the flow valve.
The ventilator uses this measurement to provide closed
loop control of the flow valve and to compute the flow
and volume delivered to the patient.
Air Delivery System Components (Continued)
Table 3-1: Air Delivery System Components

Chapter 3
3-4 BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. REF 1029568 Rev A
Theory of Operation
Electronic System Components
User Interface PCB • Motorola 68332 microcontroller
• Inter-processor communication with controller PCB
• VGA Display, Keyboard and front panel LED Interface
• Primary alarm driver
• Remote alarm relay
• USB and RS-232 serial communication
• Internal Battery charging and monitoring
• Temperature monitor
• Microcontroller watchdog and reset logic
• Voltage monitoring
Controller PCB • Blower On / Off / Closed-Loop Speed Control
• Air Flow Valve Controller
• Pressure Measurement
• RS-232 Communication
• Inter-processor communication with interface PCB
• Backup alarm driver
VGA PCB • STN Blue Mode Transmissive Viewing
• One-Quarter VGA (320 x 240)
• Dot Pitch 0.36mm x 0.36mm
Table 3-2: Electronic System Components

Chapter 3
Theory of Operation
REF 1029568 Rev A BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. 3-5
External AC/DC Power Supply • 90-240 VAC, 40-60Hz Input
• 120 Watt 18 Volt DC Output
Internal NiMH (Nickel Metal Hydride)
Battery
• 8 cell 3.8 Amp Hour provides 9.6 Volt output
nominal
• In-line thermal fuse
• Built-in thermistor for temperature monitoring
• Nominal charge time under 5 hours
• Nominal run time 45 minutes
Electronic System Components (Continued)
Table 3-2: Electronic System Components

Chapter 3
3-6 BiPAP® Focus™ Ventilator Service Manual © Respironics, Inc. REF 1029568 Rev A
Theory of Operation
Back Panel The back panel has three connection points and the On/Off switch.
• Nurse call station / serial communications port
•USBport
• AC/DC Power supply input & power cord relief clip
•ON/OFFswitch
Figure 3-1: Back Panel
Specifications Default Settings
Settings: CPAP Mode
Nurse call station/serial
communications port
USB
port
AC/DC power
supply input
Power cord relief clip
ON/OFF switch
Shown in the
OFF position
S/T mode RR = 4/min
IPAP = 12 cmH2O I-Time = 1 sec
EPAP = 4 cmH2O Ramp Time = 0 min
Rise-Time = 2 Ramp Start = 4 cmH2O
CPAP
Continuous Positive Airway
Pressure
Range: 4-20 cmH2O (4-20 hPa)
Resolution: 1 cmH2O (1 hPa)
Dynamic accuracy: ±5 cmH2O (5 hPa)
Ramp Time
Period over which the ventilator
increases inspiratory pressure
from Ramp Start setting to
CPAP setting.
Range: 0-45 min.
Resolution: 5 min.
Accuracy: ±10% of setting