SonoSite C1.9 PLUS User manual

C1.9 PLUS
Ultrasound System
Service Manual

ii C1.9 PLUS Ultrasound System Service Manual
P02287-03 01/2003
Copyright 2003 by SonoSite, Inc.
All rights reserved. Printed in the USA.

iii
Manufactured by
SonoSite, Inc.
21919 30th Drive SE
Bothell, WA 98021-3904
USA
Telephone: [phone] or [phone]
Fax: [phone]
SonoSite European Headquarters
Baystrait House, Station Road
Biggleswade SG18 8AL
UK
Telephone: [phone]
Fax: [phone]
CAUTION:
`United States federal law restricts this device to sale by or on the order of a
physician.
“SiteCharge,” “SitePack,” “SiteStand,” and “SonoHeart,” are trademarks of SonoSite, Inc.
Non-SonoSite product names may be trademarks or registered trademarks of their respective
owners.
SonoSite products may be covered by one or more of the following U.S. patents: 4454884, 4462408,
4469106, 4474184, 4475376, 4515017, 4534357, 4542653, 4543960, 4552607, 4561807, 4566035,
4567895, 4581636, 4591355, 4603702, (4607642), 4644795, 4670339, 4773140, 4817618,
4883059, 4887306, 5016641, 5050610, 5095910, 5099847, 5123415, 5158088, 5197477, 5207225,
5215094, 5226420, 5226422, 5233994, 5255682, (5275167), 5287753, 5305756, 5353354,
5365929, 5381795, 5386830, 5390674, 5402793, (5,423,220), 5438994, 5450851, 5456257,
5471989, 5471990, 5474073, 5476097, 5479930, 5482045, 5482047, 5485842, 5492134, 5517994,
5529070, 5546946, 5555887, 5603323, 5606972, 5617863, (5634465), 5634466, 5636631,
5645066, 5648942, 5669385, (5706819), 5715823, 5718229, 5720291, 5722412, 5752517,
5762067, 5782769, 5800356, 5817024, 5833613, 5846200, 5860924, 5893363, 5916168, 5951478,
6036643, 6102863, 6104126, 6113547, 6117085, 6142946, 6203498 B1, D0280762, D0285484,
D0286325, D0300241, D0306343, D0328095, D0369307, D0379231. Other patents pending.

iv C1.9 PLUS Ultrasound System Service Manual

v
Table of Contents
CHAPTER 1Introduction 1
1.1 About the System......................................................................1
1.2 Audience ...................................................................................2
1.3 Conventions Used in This Manual............................................2
1.4 About the System Software ......................................................2
1.5 Software Licensing ...................................................................3
CHAPTER 2Safety 5
2.1 Electrical Safety ........................................................................5
2.1.1 Equipment Protection .........................................................7
2.2 Battery Safety............................................................................8
2.3 Biological Safety.......................................................................9
2.4 Labeling Symbols .....................................................................9
CHAPTER 3System Overview 11
3.1 Theory of Operation................................................................11
3.1.1 Transducer ........................................................................12
3.1.2 Acquisition Subsystem .....................................................12
3.1.3 Processing Subsystem ......................................................12
3.1.4 Display Subsystem ...........................................................12
3.1.5 Control Subsystem ...........................................................12
3.1.6 User Interface Subsystem.................................................12
3.1.7 Power Subsystem .............................................................13
3.2 Components ............................................................................13
3.3 Controls...................................................................................14
3.4 Accessories .............................................................................15
3.4.1 Battery Pack .....................................................................15
3.4.1.1 Battery Charge Indicators ............................................15
3.4.2 External Power .................................................................16
3.4.2.1 External System Connections ......................................16
3.4.3 Power Adapter..................................................................17
3.5 System Specifications .............................................................17
3.5.1 Physical Dimensions ........................................................17
3.5.2 Monitor.............................................................................17
3.5.3 Transducers ......................................................................18
3.5.4 Imaging Modes.................................................................18

vi C1.9 PLUS Ultrasound System Service Manual
3.5.5 Image Storage...................................................................18
3.5.6 Temperature, Pressure, and Humidity Limits ..................18
3.5.6.1 System Operating .........................................................18
3.5.6.2 System Shipping/Storage ............................................18
3.5.6.3 Battery Operating.........................................................18
3.5.6.4 Battery Shipping/Storage .............................................18
3.5.6.5 Transducers Operating .................................................18
3.5.6.6 Transducers Shipping/Storage .....................................19
3.5.7 Electrical...........................................................................19
3.6 Battery.....................................................................................19
3.7 Safety Requirements ...............................................................19
3.7.1 Meets Electromechanical Safety Standards .....................19
3.7.2 Meets EMC/EMI Standards .............................................20
3.7.3 Meets Airborne Equipment Standards (without ECG Cable
Attached) ..........................................................................20
3.7.4 Meets ECG Standard........................................................20
CHAPTER 4Setup and Operation 21
4.1 Connecting and Removing Transducers .................................21
4.2 Turning the System On and Off..............................................22
4.3 Installing and Removing the Battery ......................................23
4.4 Using AC Power .....................................................................24
4.5 Upgrading the System Software .............................................25
4.6 Obtaining A License Key .......................................................26
4.6.1 Installing A License Key..................................................26
4.6.1.1 Displaying the System Information Screen .................28
4.7 Checking and Charging the Battery........................................28
CHAPTER 5Cleaning and Disinfecting 31
5.1 Universal Precautions .............................................................31
5.2 Receipt of Suspected Contaminated Materials .......................31
5.3 Recommended Disinfectants ..................................................32
CHAPTER 6Troubleshooting 33
6.1 System and Subsystem Diagnosis...........................................33
6.2 System Repair .........................................................................33
6.3 Test Equipment .......................................................................33

vii
6.4 Failures....................................................................................34
6.4.1 Display..............................................................................34
6.4.2 Control Panel....................................................................34
6.4.3 Trackball...........................................................................34
6.4.4 Main PCBA ......................................................................34
6.4.5 Clearing the Main PCBA Failure .....................................35
6.4.6 Battery ..............................................................................35
CHAPTER 7Replacement Procedures 43
7.1 Display Subassembly Replacement ........................................43
7.1.1 Required Parts ..................................................................43
7.1.2 Required Tools and Materials ..........................................43
7.1.3 Removing the Display Subassembly................................44
7.1.4 Replacing the Display Subassembly ................................46
7.2 Control Panel Subassembly Replacement ..............................48
7.2.1 Required Parts ..................................................................48
7.2.2 Required Tools .................................................................48
7.2.3 Removing the Control Panel Subassembly ......................49
7.2.4 Replacing the Control Panel Subassembly.......................51
7.3 Trackball .................................................................................52
7.3.1 Required Parts ..................................................................52
7.3.2 Required Tools .................................................................52
7.3.3 Removing the Trackball ...................................................52
7.3.4 Replacing the Trackball....................................................55
7.4 Main PCBA Subassembly Replacement.................................57
7.4.1 Required Parts ..................................................................57
7.4.2 Required Tools .................................................................58
7.4.3 Removing the Main PCBA Subassembly ........................58
7.4.4 Replacing the Main PCBA Subassembly.........................59
7.5 Transducers .............................................................................62
7.6 AC Power Adapter..................................................................62
7.7 OEM Peripherals.....................................................................63
7.7.1 External Monitor (Sony) ..................................................63
7.7.2 VCR (Sony)......................................................................63
7.7.3 Printer (Sony) ...................................................................63

viii C1.9 PLUS Ultrasound System Service Manual
CHAPTER 8Performance Tests 65
8.1 Overview.................................................................................65
8.2 Test Equipment:......................................................................65
8.3 Setting Up Performance Tests ................................................66
8.3.1 Scan Reference Orientation..............................................66
8.4 Testing 2D Performance .........................................................66
8.4.1 2D Image Quality .............................................................66
8.4.2 Axial Measurement Accuracy..........................................67
8.4.3 Lateral Measurement Accuracy .......................................67
8.4.4 Penetration........................................................................68
8.5 Additional Performance Tests ................................................68
8.5.1 CPD ..................................................................................68
8.5.2 PowerMap DCPD.............................................................69
8.5.3 M-mode Imaging..............................................................69
8.5.4 Tissue Harmonic Imaging ................................................70
8.5.5 Pulsed Wave (PW) Doppler Imaging...............................70
8.5.6 ECG Monitoring...............................................................70
8.5.7 Image Quality Verification Test.......................................71
8.5.8 Image Review...................................................................71
8.5.9 Printer ...............................................................................71
8.5.10 Battery Charging ..............................................................71
8.5.11 Video Output ...................................................................71
8.6 Returning Products to SonoSite..............................................72
8.6.1 Contacting SonoSite Technical Support ..........................72
8.6.2 Shipping Instructions........................................................72
APPENDIX AParts List 73
APPENDIX BService Event Report 85
Index 87

Chapter 1: Introduction 1
CHAPTER 1Introduction
Before servicing the SonoSite ultrasound system, please read the information in this
manual. This text applies to SonoSite ultrasound system products manufactured after
April 27, 2001. Please find service information about products manufactured before
April 27, 2001 in C1.51 Ultrasound System Service Manual (P00715) and C1.75
Ultrasound System Service Manual (P01118).
1.1 About the System
The SonoSite system has various configurations and features. All are described in
this manual but not every option may apply to your system. System features are
dependent on your system configuration, transducer and exam type.
The SonoSite system is a portable, software-controlled, ultrasound system. It has an
all-digital architecture. It is used to acquire and display high-resolution, real-time,
2D, Color Power Doppler (CPD), PowerMap™(PM) Directional Color Power
Doppler (DCPD), Tissue Harmonic Imaging (THI), M-mode and Pulsed Wave (PW)
Doppler ultrasound images. The system has electrocardiography (ECG), cine
review, image zoom, labeling, biopsy, measurements and calculations, serial port
connection for image transfer, image storage and review, printing and recording
capabilities. The system setup also has a selection to support optical character
recognition (OCR) of the English character set for time, date, patient name, and
patient identification. The OCR screen characters are optimized for use with the ALI
NewPORT DICOM image capture station peripheral available from ALI. For more
information about the ALI NewPORT 2.1, refer to the ALI NewPORT 2.1 Image
Capture Station User’s Guide.
Currently, the system supports the following broadband transducers:
• C60/5-2 MHz 60-mm curved array
• C15/4-2 MHz 15-mm micro-curved array
• C11/7-4 MHz 11-mm micro-curved array
• ICT/7-4 MHz 11-mm intracavitary
• L38/10-5 MHz 38-mm linear array

2 C1.9 PLUS Ultrasound System Service Manual
System accessories include a SiteStand®mobile docking station and accessories,
SiteCharge™dual battery charger, a power adapter, a battery, ECG cable, video and
printer cables, SiteLink image manager software, SiteStand®basket, Basic Stand,
CRT Stand, ScanPack quick access carrier, and SitePack™protective carry pack.
System peripherals include medical grade (conforming to the requirements of
EN60601-1) and non-medical (commercial) grade products. System medical grade
peripherals include an external color monitor, video printers, and VCRs. System
non-medical grade peripherals include a digital video recorder, a battery charger, a
lithium-ion battery, printer, and a handheld monitor. Use of peripherals is covered in
the manufacturers’ instructions, which accompany each peripheral. System setup
instructions for the use of peripherals are covered in Chapter 3 in the SonoSite
Ultasound System User Guide.
1.2 Audience
The intended audience of this manual is properly trained field and in-house service
personnel.
1.3 Conventions Used in This Manual
These conventions are used in this user guide:
• Warnings and cautions are identified with the arrow symbol.
• Control names and references to display elements are presented in bold-face
type.
• Operating instructions are introduced with a statement in bold-face type that
ends with a colon. For example: To read this user guide:
• When the steps in the operating instructions must be performed in a specific
order, the steps are numbered.
• Bulleted lists present information in list format, but they do not imply a
sequence.
• Screen display text is shown in Arial 10 pt. For example: Successful upgrade.
• The left side of the system is to your left as you face the system. The system
handle is at the top of the system, the battery compartment is at the bottom of the
system.
• Note: A note cites information that is a general rule for a procedure, gives an
exception to a rule, or provides noncritical information of general interest.
1.4 About the System Software
Your SonoSite system contains software that controls its operation. From time to
time, SonoSite may provide new software for use with your system. This software is
provided using a software update module or a transducer. This software may be
either required or optional. A single module or transducer can be used to update one
or more systems.
When the new software is required, you must install it if you wish to use the new
software features (e.g., new transducer). If you choose not to install it, you must

Chapter 1: Introduction 3
remove the transducer and replace it with one that is compatible with the software
that is currently installed in your system.
When the software is optional, you can either install it or choose to use your existing
software. If you choose not to install the software, the system will prompt you again
whenever the system is started, and whenever the transducer is disconnected and
then reconnected to the system. For more information on software upgrades, refer to
Chapter 4.5, Upgrading the System Software, on page 25.
1.5 Software Licensing
Use of the software that you receive from SonoSite is controlled by a license key. A
license key is a number sequence containing exactly 12 decimal digits.
License keys are obtained from SonoSite or from its authorized representatives. You
must obtain one key for each system that will use the new software. See
Chapter 4.6, Obtaining A License Key, on page 26 for information on obtaining a
license key.
Software that you receive from SonoSite may be installed and will operate for a
short period of time without requiring a valid license key. We refer to this period of
time as the “grace period.” The grace period is variable.
When you first install your software, your SonoSite system will prompt you for a
license key. If you have not yet obtained a valid license key, you can elect to use the
software as long as the grace period time has not been fully consumed. We refer to
this mode of operation as “running in the grace period.”
When a system is running in the grace period, all system functions are available. As
you use the system, the grace period is slowly consumed. When the grace period has
expired, the system will not be usable until a valid license key has been entered.
Grace period time is not consumed while the system is powered off or when it is in
“sleep” mode. Whenever a system is running in the grace period, the grace period
time remaining is available on the license update screen. Refer to Chapter 4.6.1.1,
Displaying the System Information Screen, on page 28.
CAUTION:
`When the grace period expires, all system functions except for licensing will be
unavailable until you enter a valid license key into the system.

4 C1.9 PLUS Ultrasound System Service Manual
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Chapter 2: Safety 5
CHAPTER 2Safety
Please read this information before using the SonoSite ultrasound system. It applies
to the ultrasound system, transducers, accessories, and peripherals.
A WARNING describes precautions necessary to prevent injury or loss of life.
A CAUTION describes precautions necessary to protect the products.
2.1 Electrical Safety
This system meets EN60601-1, Class I/internally-powered equipment requirements
and Type BF isolated patient-applied parts safety requirements. The ECG cable
meets safety requirements of EN 60601-2-25 for Type CF patient-applied part.
This system complies with the applicable medical equipment requirements
published in the Canadian Standards Association (CSA), European Norm
Harmonized Standard, and Underwriters Laboratories (UL) safety standards. See
Chapter 3.5, System Specifications, on page 17.
For maximum safety observe the following warnings and cautions:
WARNINGS:
`To avoid discomfort or minor risk of patient injury, keep hot surfaces away from
the patient.
`Under certain circumstances, the transducer connector and back of the display
enclosure can reach temperatures that exceed EN60601-1 limits for patient
contact, therefore only the operator shall handle the system. This does not include
the transducer face.
`To avoid discomfort or minor risk of operator injury when handling the transducer
connector, the system should not be operated for more than 60 minutes
continuously in a live-scan mode (as opposed to freeze or sleep modes).

6 C1.9 PLUS Ultrasound System Service Manual
`To avoid the risk of electrical shock or injury, do not open the system enclosures.
All internal adjustments and replacements, except battery replacement, must be
made by a qualified technician.
`To avoid the risk of injury, do not operate the system in the presence of flammable
gasses or anesthetics. Explosion can result.
`To avoid the risk of electrical shock, use only properly grounded equipment.
Shock hazards exist if the AC power adapter is not properly grounded. Grounding
reliability can only be achieved when equipment is connected to a receptacle
marked “Hospital Only” or “Hospital Grade” or the equivalent. The grounding
wire must not be removed or defeated.
`To avoid the risk of electrical shock, before using the transducer, inspect the
transducer face, housing, and cable. Do not use the transducer, if the transducer or
cable is damaged.
`To avoid the risk of electrical shock, always disconnect the AC power adapter
from the system before cleaning the system.
`To avoid the risk of electrical shock, do not use any transducer that has been
immersed beyond the specified cleaning or disinfection level. Refer to the
SonoSite Ultrasound System User Guide for cleaning and disinfection levels.
`To avoid the risk of electrical shock and fire hazard, inspect the AC power adapter
cord and plug on a regular basis. Ensure they are not damaged.
`To avoid the risk of electrical shock, use only accessories and peripherals
recommended by SonoSite. Connection of accessories and peripherals not
recommended by SonoSite could result in electrical shock. Contact SonoSite or
your local representative for a list of accessories and peripherals available from or
recommend by SonoSite.
`To avoid the risk of electrical shock, use commercial grade peripherals
recommended by SonoSite on battery power only. Do not connect these products
to AC mains power when using the system to scan or diagnose a patient/subject.
Contact SonoSite or your local representative for a list of the commercial grade
peripherals available from or recommended by SonoSite.
`To prevent injury, only use market cleared ECG electrodes and cables.
`To avoid the risk of electrical shock to the patient/subject, ensure proper assembly
of the ECG electrodes and cables.
`To avoid the risk of electrical shock to the patient/subject, do not touch the system
battery contacts while simultaneously touching a patient/subject.
`To prevent injury to the operator/bystander, the transducer must be removed from
patient contact before the application of a high-voltage defibrillation pulse.
CAUTIONS:
`Although your system has been manufactured in compliance with existing EMC/
EMI requirements (EN60601-1-2), use of the system in the presence of
an electromagnetic field can cause degradation of the ultrasound image. If this
occurs often, SonoSite suggests a review of the system environment. Identify and
remove the possible sources of the emissions or move your system.

Chapter 2: Safety 7
`Electrostatic discharge (ESD), or static shock, is a naturally occurring
phenomenon. ESD is common in conditions of low humidity, which can be caused
by heating or air conditioning. Static shock is a discharge of the electrical energy
from a charged body to a lesser or non-charged body. The degree of discharge can
be significant enough to cause damage to a transducer or an ultrasound system.
The following precautions can help reduce ESD: anti-static spray on carpets, anti-
static spray on linoleum, and anti-static mats.
`Do not use the system if an error message appears on the image display: note the
error code; call SonoSite or your local representative; turn off the system by
pressing and holding the power switch until the system powers down.
`To avoid increasing the system and transducer connector temperature, do not
block the airflow to the ventilation holes on the back of the system.
2.1.1 Equipment Protection
To protect your ultrasound system, transducer, and accessories, follow these
precautions.
To protect your ultrasound system, transducer, and accessories, follow these
precautions.
CAUTIONS:
`The ECG cable emits electromagnetic interference when connected to the
SonoSite system. It is not approved for use in-flight on aircraft.
`Excessive bending or twisting of cables can cause a failure or intermittent
operation.
`Improper cleaning or disinfecting of any part of the system can cause permanent
damage. For cleaning and disinfecting instructions, refer to the SonoSite
Ultrasound System User Guide.
`Do not submerge the transducer connector in solution. The cable is not liquid-tight
beyond the transducer connector/cable interface.
`Do not use solvents such as thinner or benzene, or abrasive cleaners on any part
of the system.
`Remove the battery from the system if the system is not likely to be used for some
time.
`Do not spill liquid on the system.
`The top membrane of the phantom is delicate and can be damaged if handled
improperly. Use minimum force when coupling the transducer to the phantom.
`Do not handle PCBs without proper static protection. Improper handling may
damage components.
`Incorrect assembly or configuration or using an improper power source may
damage the system.
`Do not touch the scanhead connector pins.

8 C1.9 PLUS Ultrasound System Service Manual
2.2 Battery Safety
To avoid the risk of injury, follow the warnings and cautions to make sure that the
battery does not burst, ignite, or generate heat or fumes.
WARNINGS:
`The battery has a safety device. Do not disassemble or alter the battery.
`Charge the batteries only when the ambient temperature is between 0° and 40°C
(32° and 104°F).
`Do not short-circuit the battery by directly connecting the positive and negative
terminals with metal objects.
`Do not heat the battery or discard it in a fire.
`Do not expose the battery to temperatures over 60°C (140°F). Keep it away from
fire and other heat sources.
`Do not charge the battery near a heat source, such as a fire or heater.
`Do not leave the battery in direct sunlight.
`Recharge the battery only with the SiteCharge™ dual battery charger or the
system.
`Do not pierce the battery with a sharp object, hit it, or step on it.
`Do not use a damaged battery.
`Do not solder a battery.
`When connecting the battery to the SiteCharge™ dual battery charger or to the
system, never reverse the polarity of the battery terminals.
`The polarity of the battery terminals are fixed and cannot be switched or reversed.
Do not force the battery into the system or the SiteCharge™ dual battery charger.
`Do not connect the battery to an electrical power outlet.
`Do not continue recharging the battery if it does not recharge after two successive
six hour charging cycles.
CAUTIONS:
`To avoid the battery bursting, igniting, or fumes from the battery and causing
equipment damage, observe the following precautions:
`Do not immerse the battery in water or allow it to get wet.
`Do not put the battery into a microwave oven or pressurized container.
`If the battery leaks or emits an odor, remove it from all possible flammable
sources.
`If the battery emits an odor or heat, is deformed or discolored, or in any way
appears abnormal during use, recharging or storage, immediately remove it and
stop using it. If you have any questions about the battery, consult SonoSite or your
local representative.
`Store the battery between -20°C (-4°F) and 60°C (140°F).
`Use only SonoSite batteries.

Chapter 2: Safety 9
2.3 Biological Safety
Observe the following precautions related to biological safety.
WARNINGS:
`To prevent misdiagnosis, do not use the ECG trace to diagnosis cardiac rhythms.
The SonoSite ECG option is a non-diagnostic feature.
`To prevent injury, only use market cleared ECG electrodes and cables.
`Non-medical (commercial) grade peripheral monitors have not been verified or
validated by SonoSite as being suitable for diagnosis.
`Do not use the system if it exhibits erratic or inconsistent behavior. Discontinuities
in the scanning sequence are indicative of a hardware failure that must be
corrected before use.
`Do not use the system if it exhibits artifacts on the LCD screen, either within the
clinical image or in the area outside of the clinical image. Artifacts are indicative
of hardware and/or software errors that must be corrected before use.
`Some transducer covers contain natural rubber latex and talc, which can cause
allergic reactions in some individuals. Refer to the FDA Medical Alert, March 29,
1991.
`Perform ultrasound procedures prudently. Use the ALARA (as low as reasonably
achievable) principle.
`SonoSite does not currently recommend a specific brand of acoustic standoff.
2.4 Labeling Symbols
Labeling symbols for SonoSite products can be found in the user guide for each
product.

10 C1.9 PLUS Ultrasound System Service Manual
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Chapter 3: System Overview 11
CHAPTER 3System Overview
3.1 Theory of Operation
The SonoSite ultrasound system has seven major functional groups: the transducer,
the acquisition subsystem, the processing subsystem, the display subsystem, the
control subsystem, the user interface subsystem, and the power subsystem.
Figure 3.1 shows how these functions interact.
Figure 3.1 System Block Diagram
Acquisition
subsystem
Processing
subsystem
Display
subsystem
User
interface
subsystem
Power
subsystem
Video bus
External video to monitor,
VCR, printer ports
Control
subsystem
RF bus
Control bus
Pulser voltage
Power
adapter
External power
Battery
pack
Transducer
AQ bus
Display power
Logic power
Serial bus
To all
subsystems

12 C1.9 PLUS Ultrasound System Service Manual
3.1.1 Transducer
The transducer elements convert the pulser voltage to acoustic energy during the
“transmit” portion of the ultrasound acquisition cycle. Also, the transducer elements
convert the acoustic echo to voltage in the “receive” portion of the acquisition cycle.
The system transducers have more than 64 elements. The acquisition subsystem
senses the voltage developed on the transducer elements.
3.1.2 Acquisition Subsystem
The acquisition subsystem consists of a beamformer and an interface to the
transducer. The beamformer times the “transmit” pulses to focus the acoustic beam.
Also, the beamformer amplifies the low-level echo signal and times and focuses the
“receive” information.
3.1.3 Processing Subsystem
The high-speed processing subsystem interfaces with the beamformer. The
processing subsystem demodulates, filters, detects, and compresses the signal
supplied by the beamformer. Next, it sends this data to the display subsystem.
3.1.4 Display Subsystem
The display subsystem converts the detected ultrasound data into picture elements
(pixels). The software user interface graphics are combined with the ultrasound
information and converted to a video stream. The external video ports support NTSC
and PAL format.
3.1.5 Control Subsystem
The control subsystem consists of the central processing unit, program and video
memory, permanent image storage and retrieval memory, and a connection to the
user interface keys. The control software includes the acoustic power and intensity
software power group monitors, and a beamformer monitor. This software makes the
system operate within acoustic power and intensity limits, which guarantees a level
of patient safety.
3.1.6 User Interface Subsystem
The user interface subsystem comprises the software user interface and the form
factor. The software user interface is the interaction between the user and the screen
layout components. The form factor is the device’s physical attributes: buttons,
location and grouping of buttons and the device size, shape, and weight. Dedicated
controls, or often-used features, are grouped according to user workflow.