Hologic QDR 4500 Technical Manual



HOLOGIC

MODEL QDR®4500

FAN BEAM X-RAY BONE DENSITOMETER

TECHNICAL MANUAL

Hologic Inc.

35 Crosby Drive Bedford, MA 01730 USA

Phone in US:

Fax (Domestic): 781-280-0670

Fax (International): 781-280-0671

800-321-4659

Document # 080-0462

Revision E

NOTICE

The information contained in this Manual is confidential and proprietary to Hologic, Inc. This information is provided only to authorized representatives of Hologic's customers solely for the purpose of facilitating the use of Hologic's products. No information contained herein may be disclosed to any unauthorized person for any purpose whatsoever without the prior written consent of Hologic, Inc.

Hologic products and company names, used in this manual, are trademarks and registered trademarks of other manufacturers.

The procedures described in this document are intended solely for use by direct employees of Hologic, Inc. or authorized Hologic Equipment Resellers and their trained technicians. Any unauthorized or untrained persons performing these procedures may affect the warranty of the Hologic Model QDR 4500.

Exercise proper caution when servicing the system. There are dangerous and potentially lethal voltages accessible within the QDR 4500 system. To avoid exposure to shock hazards, the Main circuit breaker should be switched off, and the power cord removed, before working inside any part of the system.

The QDR 4500 Fan Beam X-ray Bone Densitometer produces ionizing radiation in the form of X-rays. It may be dangerous to the patient, operator or service technician unless safe exposure factors and operating instructions are observed. To avoid unsafe exposure, do not attempt to service this equipment unless you are a Hologic, Inc. certified service technician. Exercise proper caution when servicing the system. A dosimeter (film badge) should always be worn while on site. Dose and scatter radiation measurements must be taken after each service call to ensure that these parameters are still within specifications.

Hologic, Inc. has made all reasonable effort to ensure that the information in this manual is accurate and complete. Hologic, Inc. shall not, however, be liable for any technical or editorial errors or omissions contained herein, or for incidental, special or consequential damages in connection with the furnishing or use of this material. The information contained in this manual is subject to change without notice.

QDR 4500

and the Hologic logo are registered trade marks of Hologic, Inc. All other

Printed in U.S.A.



RECORD OF REVISIONS

Document # 080- 0462

Date: Revision: Description:

3/95 A Release document per ECO 2501. 5/95 B Revised to include information about models QDR 4500W and QDR

4500C per ECO 2597

12/96 C Revised per ECO 3279

6/98 D Add FDA required information about system specifications (Section 1).

Add new Leakage Testing Procedure on page 3-25. Add Reproducibility Test on page 3-27. Add information about Radiation Measurement Report on page 3-28. Other revisions per ECO 3822.

4/99 E Revise per ECO 4221.

iii

TABLE OF CONTENTS

SECTION 1 INTRODUCTION .....................................................................................................1-1

SYSTEM OVERVIEW.............................................................................................................................................1-1

X-RAY SCANNING THEORY................................................................................................................................1-2

FUNCTIONAL OVERVIEW....................................................................................................................................1-4

PRODUCT SPECIFICATIONS................................................................................................................................1-8

BMD Precision:...................................................................................................................................................1-10

Duty Cycle:.........................................................................................................................................................1-10

Leakage Technique Factors................................................................................................................................. 1-10

Minimum Beam Filtration...................................................................................................................................1-10

Measured Half Value Layer (HVL) At Different Operating Potentials.............................................................. .1-11

Line Voltage and Maximum Line Current..........................................................................................................1-11

Technique Factors for Maximum Line Current...................................................................................................1-11

Maximum Deviation............................................................................................................................................1-11

Measurement Criteria for Technique Factors......................................................................................................1-11

SECTION 2 FUNCTIONAL DESCRIPTION................................................................................2-1

COMPUTER .............................................................................................................................................................2-1

COMMUNICATIONS CONTROLLER BOARD.....................................................................................................2-1

Interface Connections............................................................................................................................................2-1

DISTRIBUTION BOARD.........................................................................................................................................2-3

Power ....................................................................................................................................................................2-3

Interface Connections............................................................................................................................................2-4

MOTOR CONTROLLER BOARD...........................................................................................................................2-5

Power ....................................................................................................................................................................2-5

Interface Connections............................................................................................................................................2-6

TZ DRIVE BOARD..................................................................................................................................................2-7

Service Switches....................................................................................................................................................2-7

Power ....................................................................................................................................................................2-8

Interface Connections............................................................................................................................................2-8

CONTROL PANEL CONTROLLER BOARD................................................................................................. ......2-11

Power ..................................................................................................................................................................2-11

Interface Connections..........................................................................................................................................2-12

C-ARM INTERFACE BOARD...............................................................................................................................2-15

Continuity Daisy Chain.......................................................................................................................................2-15

Power ..................................................................................................................................................................2-15

Interface Connections..........................................................................................................................................2-16

X-RAY CONTROLLER ASSEMBLY....................................................................................................................2-18

Interface...............................................................................................................................................................2-18

X-Ray Controller Assembly Boards............................................................................................... .....................2-20

I/O and Logic Board.......................................................................................................................................2-20

Low Voltage Power Supply............................................................................................................................2-20

Power Factor Regulator (PFR) Substitution Board.........................................................................................2-21

Duty Cycle Regulator......................................................................................................................................2-21

H-Bridge Board...............................................................................................................................................2-21

Interface Connections.....................................................................................................................................2-21

X-RAY SOURCE UNIT..........................................................................................................................................2-26

DATA ACQUISITION SYSTEM...........................................................................................................................2-26

Solid State Detector.............................................................................................................................................2-27

Power..............................................................................................................................................................2-27

Interface Connections.....................................................................................................................................2-27

INTEGRATOR/MULTIPLEXOR BOARD............................................................................................................2-28

Power..............................................................................................................................................................2-29

Interface Connections.....................................................................................................................................2-29

Analog To Digital Board.....................................................................................................................................2-30

Power..............................................................................................................................................................2-31

Interface Connections......................................................................................................................................2-31

POWER MODULE .................................................................................................................................................2-32

SECTION 3 INSTALLATION.......................................................................................................3-1

REQUIRED TOOLS..................................................................................................................................................3-1

REQUIRED DOCUMENTATION............................................................................................................................3-1

ROOM AND DOORWAY SIZE...............................................................................................................................3-2

ARRANGE FOR HELP.............................................................................................................................................3-4

INSPECT FOR VISIBLE SHIPPING DAMAGE .....................................................................................................3-4

UNCRATE UNIT......................................................................................................................................................3-5

INSPECT FOR HIDDEN SHIPPING DAMAGE .....................................................................................................3-6

TAKE INVENTORY.................................................................................................................................................3-6

MEASURE PATH TO FINAL DESTINATION.......................................................................................................3-6

Short Doorway.......................................................................................................................................................3-6

Narrow Hallway.....................................................................................................................................................3-7

REMOVE TABLE TOP (IF NECESSARY).............................................................................................................3-7

REMOVE QDR 4500A, OR SL, C-ARM (IF NECESSARY)..................................................................................3-8

PREPARING THE TABLE TOP FOR MOVING (SL only)..................................................................................3-10

MOVE UNIT TO DESTINATION (VERTICAL POSITION)................................................................................3-10

MOVE UNIT TO DESTINATION (HORIZONTAL POSITION)..........................................................................3-11

SET UP UNIT..........................................................................................................................................................3-13

INSTALL QDR 4500A, OR QDR 4500SL, UPPER C-ARM .................................................................................3-15

INSTALL QDR 4500W, OR QDR 4500C, C-ARM................................................................................................3-16

INSTALL COMPUTER ..........................................................................................................................................3-17

INSTALL CABLES.................................................................................................................................................3-17

SAFETY PRECAUTIONS......................................................................................................................................3-18

CHECK POWER LINE VOLTAGE........................................................................................................................3-18

Measure Line Voltage.........................................................................................................................................3-18

Measure Isolation Transformer Secondary Voltage.............................................................................................3-18

CHECK TUBE KV PEAK POTENTIAL................................................................................................................3-19

CHECK TUBE CURRENT.....................................................................................................................................3-21

CHECK BELT TENSION.......................................................................................................................................3-23

ADJUST C-ARM Y BELT......................................................................................................................................3-23

CALIBRATE MOTORS..........................................................................................................................................3-23

CHECK X-RAY BEAM ALIGNMENT..................................................................................................................3-23

CALIBRATE APERTURE (QDR 4500A AND SL)...............................................................................................3-23

CHECK LASER POSITIONING OFFSET.............................................................................................................3-24

ADJUST A/D GAIN CONTROL.............................................................................................................................3-24

PERFORM BEAM FLATTENING.........................................................................................................................3-24

PERFORM LATERAL ALIGNMENT TEST.........................................................................................................3-24

MEASURE X-RAY DOSE TO PATIENT ..............................................................................................................3-24

CHECK HVPS/S (TANK) FOR RADIATION LEAKAGE....................................................................................3-25

CALIBRATE FOR AREA, BMD AND BMC.........................................................................................................3-26

TEST SCAN MODES.............................................................................................................................................3-26

FINISH ASSEMBLING UNIT................................................................................................................................3-26

MEASURE X-RAY SCATTER FROM PHANTOM..............................................................................................3-27

PERFORM QC........................................................................................................................................................3-27

RUN REPRODUCIBILITY TEST..........................................................................................................................3-27

THE RADIATION MEASUREMENT REPORT....................................................................................................3-29

SECTION 4 ALIGNMENT AND CALIBRATION.........................................................................4-1

TABLE ALIGNMENT..............................................................................................................................................4-1

Checking Table Alignment....................................................................................................................................4-1

Aligning Table.......................................................................................................................................................4-1

Table Edge to T-Rail (“A” Dimension) Adjustment.........................................................................................4-1

Front to Back T-Rail and Table Edge/Rail Gap Adjustment .............................................................................4-3

C-ARM PARALLELISM ADJUSTMENT (A and SL only).....................................................................................4-3

X-RAY BEAM ALIGNMENT (A and SL only) .......................................................................................................4-4

X-RAY BEAM ALIGNMENT (C and W only)........................................................................................................4-8

APERTURE CALIBRATION (A and SL only) ........................................................................................................4-9

MOTOR CALIBRATION.........................................................................................................................................4-9

MOTOR$TZ (QDR 4500A and SL) ...................................................................................................................4-10

MOTOR$AY (all QDR 4500 models) ................................................................................................................4-12

MOTOR$TY (QDR 4500A and W)....................................................................................................................4-16

MOTOR$TX (all QDR 4500 models).................................................................................................................4-19

MOTOR$AR (QDR 4500A and SL)...................................................................................................................4-22

LASER POSITIONING OFFSET ADJUSTMENT.................................................................................................4-27

A/D GAIN CONTROL ADJUSTMENT.................................................................................................................4-27

BEAM FLATTENING............................................................................................................................................4-28

X-RAY BEAM ALIGNMENT "AIRSCAN" TEST...............................................................................................4-30

Machines using Body Composition Analysis (BCA)..........................................................................................4-31

Machines using BMD Whole Body Analysis......................................................................................................4-31

LATERAL ALIGNMENT TEST (QDR 4500A AND SL)......................................................................................4-31

AREA, BMD AND BMC CALIBRATION.............................................................................................................4-33

Scan Thickness Measurement & Calibration (QDR 4500A and SL)..................................................................4-33

Scan Thickness Measurement & Calibration (QDR 4500W and C)....................................................................4-36

Calibration of Area and BMC, for Array Scan Modes........................................................................................4-38

Adding Array AP Scans to the QC Database.......................................................................................................4-39

SECTION 5 REMOVE AND REPLACE PROCEDURES............................................................5-1

RECOMMENDED TOOLS......................................................................................................................................5-1

ELECTRONICS TRAY FRUS..................................................................................................................................5-1

Electronics Tray Printed Circuit Boards................................................................................................................5-1

C-Arm Y Belt ........................................................................................................................................................5-2

C-Arm Y Motor or Gearcase.................................................................................................................................5-3

C-Arm Y Encoder................................................................................................................................................. 5-4

CONTROL PANEL AND TABLE Y FRUS.............................................................................................................5-4

Control Panel.........................................................................................................................................................5-5

PCBs Under Right-Side of the Table....................................................................................................................5-5

Table Y Belt..........................................................................................................................................................5-6

Table Y Motor or Gearcase...................................................................................................... .............................5-6

Table Y Encoder....................................................................................................................................................5-7

TABLE X FRUS........................................................................................................................................................5-8

Table X Motor Controller PCB.............................................................................................................................5-8

Table X Belt..........................................................................................................................................................5-9

Table X Motor or Gearcase...................................................................................................... ...........................5-10

Table X Encoder .................................................................................................................................................5-10

TABLE Z FRUS (A and SL only)...........................................................................................................................5-11

Pedestal ...............................................................................................................................................................5-11

Linear Potentiometer (Encoder- Obsolete)..........................................................................................................5-13

The Linear Rotary String (Encoder)....................................................................................................................5-13

Installation......................................................................................................................................................5-13

ARM R FRUS .........................................................................................................................................................5-15

Motor Controller Board.......................................................................................................................................5-15

Arm R Belt..........................................................................................................................................................5-16

Arm R Motor, Gearcase, Encoder or Encoder Belt.............................................................................................5-16

Gas Spring...........................................................................................................................................................5-18

LOWER C-ARM FRUS..........................................................................................................................................5-18

C-Arm Interface Board........................................................................................................................................5-18

X-Ray Controller Assembly................................................................................................................................5-18

Filter Drum Assembly........................................................................................................... ..............................5-20

Tank Assembly....................................................................................................................................................5-21

UPPER C-ARM FRUS............................................................................................................................................5-23

Integrator/Multiplexor Board..............................................................................................................................5-23

Detector Boards...................................................................................................................................................5-24

Laser Assembly...................................................................................................................................................5-25

REAR C-ARM FRUS..............................................................................................................................................5-26

Analog to Digital Converter Board......................................................................................................................5-26

POWER MODULE FRUS.......................................................................................................................................5-27

28 Volt Power Supply.........................................................................................................................................5-27

15 Volt Power Supply.......................................................................................................................................5-28

Line Filter .................................................................................................................... ........................................5-29

Isolation Transformer ..........................................................................................................................................5-29

Power Controller Board.......................................................................................................................................5-29

OPERATOR'S CONSOLE FRUS ...........................................................................................................................5-30

APERTURE ASSEMBLY FRUS............................................................................................................................5-32

Aperture Stepper Motor.......................................................................................................................................5-32

Aperture Motor PCB...........................................................................................................................................5-33

Aperture Position Belt.........................................................................................................................................5-33

Rotary Potentiometer...........................................................................................................................................5-34

DRUM ASSEMBLY FRUS....................................................................................................................................5-34

Drum Encoder PCB.............................................................................................................................................5-34

Drum Belts ..........................................................................................................................................................5-35

Stepper Motor Assembly.....................................................................................................................................5-36

Drum Bearings.....................................................................................................................................................5-37

REPLACING EMI CABLES ...................................................................................................................................5-39

FRU LISTS..............................................................................................................................................................5-41

Figure 5-1. Electronics Tray FRUs...................................................................................................................... 5-41

Figure 5-2. Control Panel and Table Y FRUs.....................................................................................................5-41

Figure 5-3. Left Side Table Y FRUs....................................................................................................................5-41

Figure 5-4. Table X FRUs...................................................................................................................................5-42

Figure 5-5. Table Z FRUs....................................................................................................................................5-42

Figure 5-6. Installing the Rotary String Encoder.................................................................................................5-42

Figure 5-7 C-Arm R FRUs (Outside View).........................................................................................................5-42

Figure 5-8. C-Arm R FRUs (Inside View) ..........................................................................................................5-43

Figure 5-9. Lower C-Arm FRUs..........................................................................................................................5-43

Figure 5-11. Upper C-Arm FRUs........................................................................................................................5-43

Figure 5-12. Detector Assembly Mounting.........................................................................................................5-43

Figure 5-13. Laser Assembly...............................................................................................................................5-44

Figure 5-14. Rear C-Arm FRUs ..........................................................................................................................5-44

Figure 5-15. Power Module FRUs ......................................................................................................................5-44

Figure 5-16. Power Control Panel FRUs.............................................................................................................5-44

Figure 5-17. Operator's Console Assemblies.......................................................................................................5-45

Figure 5-18. Computer Assemblies.....................................................................................................................5-46

Figure 5-19. Aperture Assembly FRUs (QDR 4500A and SL)...........................................................................5-46

Figure 5-22. Front Drum Assembly FRUs...........................................................................................................5-46

Figure 5-23. Drum Outer Bearings......................................................................................................................5-47

Figure 5-24. Drum Inner Bearings.......................................................................................................................5-47

Cables..................................................................................................................................................................5-47

Miscellaneous......................................................................................................................................................5-47

Mobile.................................................................................................................................................................5-48

Special Tools.......................................................................................................................................................5-48

SECTION 6 FAULT ISOLATION.................................................................................................6-1

BEFORE STARTING................................................................................................................................................6-1

SOFTWARE CONFIGURATION.............................................................................................................................6-1

HARDWARE CONFIGURATION...........................................................................................................................6-1

POWER PROBLEMS ............................................................................................................................................... 6-1

MOTION PROBLEMS..............................................................................................................................................6-2

CONTROL PANEL PROBLEMS.............................................................................................................................6-5

DISPLAY PROBLEMS.............................................................................................................................................6-5

Vertical Stripe........................................................................................................................................................6-6

Horizontal Stripe...................................................................................................................................................6-6

Noise......................................................................................................................................................................6-6

No Display.............................................................................................................................................................6-7

vii

TARGETING/LASER PROBLEMS.........................................................................................................................6-8

DATA COMMUNICATIONS PROBLEMS.............................................................................................................6-8

AREA /BMD/BMC/CV SPECIFICATION PROBLEMS.........................................................................................6-9

X-RAY PROBLEMS.................................................................................................................................................6-9

No X-Rays.............................................................................................................................................................6-9

X-Ray Alignment Problems ................................................................................................................................6-10

Beam Flattening Problems ..................................................................................................................................6-11

LASER PROBLEMS...............................................................................................................................................6-12

OIL LEAKAGE.......................................................................................................................................................6-13

The Torque Specifications...................................................................................................................................6-13

Tank Top Cover Components and Screw Location.............................................................................................6-13

Tightening the Lexan Cup Screws.......................................................................................................................6-14

Tightening the Bladder Gasket Screws................................................................................................................6-14

Tightening the Transformer Seal Screws.............................................................................................................6-14

Tightening the Tank Cover Gasket Screws..........................................................................................................6-15

MISCELLANEOUS PROBLEMS ..........................................................................................................................6-16

MESSAGES............................................................................................................................................................6-16

NO A/C LINE INTERRUPTS.................................................................................................................................6-17

ERROR MESSAGE LIST.......................................................................................................................................6-19

SECTION 7 PREVENTIVE MAINTENANCE...............................................................................7-1

CUSTOMER PREVENTIVE MAINTENANCE......................................................................................................7-1

FIELD SERVICE PREVENTIVE MAINTENANCE...............................................................................................7-1

Guide Rail and Bearing Maintenance....................................................................................................................7-2

SECTION 8 PCB SUMMARY INFORMATION ...........................................................................8-1

Power Distribution................................................................................................................................................8-1

ADC......................................................................................................................................................................8-1

Signal Distribution............................................................................................................ ....................................8-2

Communications Controller..................................................................................................................................8-2

Detector Array Assembly......................................................................................................................................8-3

TZ Drive................................................................................................................................................................8-3

Stepper Motor Controller......................................................................................................................................8-4

Control Panel Controller.......................................................................................................................................8-4

SECTION 9 SOFTWARE TOOLS...............................................................................................9-1

SUSQ ....................................................................................................................................................................9-1

SQKEYPAD .........................................................................................................................................................9-4

APPENDIX A SOFTWARE DEINSTALLATION/INSTALLATION...................................................1

APPENDIX B CROSS-CALIBRATION............................................................................................1

viii

TABLE OF FIGURES

Figure 1-1. QDR 4500 ................................................................................................................1-2

Figure 1-2. Q Scan Plot.................................................................................................................1-3

Figure 1-3. QDR 4500 Block Diagram (Operator's Console).......................................................1-4

Figure 1-4. QDR 4500 Block Diagram (Scanner Unit) ................................................................1-5

Figure 1-5. QDR 4500 Block Diagram (C-Arm Subsystem)........................................................1-6

Figure 2-1. Communications Controller Board/Distribution Board Interconnection Diagram....2-3

Figure 2-2. Distribution Board High Level Interconnection Diagram..........................................2-4

Figure 2-3. Distribution Board/Motor Controller Board Interconnection Diagram.....................2-6

Figure 2-4. Distribution Board/TZ Drive Board Interconnection Diagram..................................2-9

Figure 2-5. Control Panel Controller Interconnection Diagram ...............................................2-12

Figure 2-6. Distribution Board/C-Arm Interface Board Interconnection Diagram....................2-16

Figure 2-7. C-Arm Interface Board High Level Interconnection Diagram................................2-18

Figure 2-8. C-Arm Interface Board/X-Ray Controller Assembly Interconnection Diagram....2-19

Figure 2-9. X-Ray Controller Assembly High-Level Interconnection Diagram........................2-21

Figure 2-10. Low Voltage Power Supply Board Interconnections............................................2-22

Figure 2-11. PFR Substitution Board/I/O and Logic Board Interconnection Diagram.............2-24

Figure 2-12. I/O and Logic Board/H-Bridge Board Interconnection Diagram..........................2-24

Figure 2-13. I/O and Logic Board/Duty Cycle Driver Board Interconnection Diagram...........2-25

Figure 2-14. H-Bridge Board/Duty Cycle Driver Board Interconnection Diagram...................2-25

Figure 2-15. Integrator/Multiplexor Board/Solid State Detector Boards Interconnection Diagram2-27 Figure 2-16. Analog Digital Converter Board/Integrator Multiplexor Board Interconnection

Diagram..................................................................................................................2-29

Figure 2-17. C-Arm Interface Board/Analog/Digital Converter Board Interconnection Diagram2-31

Figure 2-18. Power Module Block Diagram..............................................................................2-33

Figure 3-1. Room Layout (4500A) ...............................................................................................3-2

Figure 3-2. System Dimensions (4500SL)....................................................................................3-3

Figure 3-3. System Dimensions (4500W).....................................................................................3-3

Figure 3-4. System Dimensions (4500C)......................................................................................3-4

Figure 3-5. Crated Unit (QDR 4500A and QDR 4500SL) ...........................................................3-5

Figure 3-6. Uncrated Unit (QDR 4500A and QDR 4500 SL) ......................................................3-7

Figure 3-7. Table X Drive.............................................................................................................3-8

Figure 3-8. Tipping Unit...............................................................................................................3-9

Figure 3-9. Moving and Tilting the Unit Down..........................................................................3-11

Figure 3-10. Auxiliary Horizontal Caster Installation................................................................3-12

Figure 3-11. Shipping Bracket Locations (QDR 4500A and SL)...............................................3-13

Figure 3-12. Shipping Bracket Locations (QDR 4500A and SL)...............................................3-14

Figure 3-13. Shipping Bracket Locations (QDR 4500W and C)................................................3-14

Figure 3-14. Shipping Bracket Location (QDR 4500W and C)..................................................3-15

Figure 3-15. Repositioning the Belt Tensioning Mechanism.....................................................3-16

Figure 3-16. Isolation Transformer Taps....................................................................................3-17

Figure 3-17. Peak Potential Mode 4............................................................................................3-20

Figure 3-18. Peak Potential Mode 3............................................................................................3-20

Figure 3-19. Tube Current Mode 1.............................................................................................3-22

Figure 3-20. Tube Current Mode 3.............................................................................................3-22

Figure 3-21. Leakage Test Shield (099-0566)............................................................................3-25

Figure 4-1. Table Alignment.........................................................................................................4-2

Figure 4-2. Pedestal (covers removed)..........................................................................................4-3

Figure 4-3. X-Ray Alignment Fixture (010-0923)........................................................................4-4

Figure 4-4. Inserting The X-Ray Alignment Fixture ....................................................................4-5

Figure 4-5. The Alignment Fixture Properly Installed..................................................................4-6

Figure 4-6. Filter Drum Adjustments - Top View ........................................................................4-6

Figure 4-7. Array Assembly - Top View, Partial..........................................................................4-7

Figure 5-1. Electronics Tray FRUs...............................................................................................5-3

Figure 5-2. Control Panel and Table Y FRUs...............................................................................5-5

Figure 5-3. Left Side Table Y FRUs.............................................................................................5-7

Figure 5-4. Table X FRUs.............................................................................................................5-9

Figure 5-5. Table Z FRUs...........................................................................................................5-12

Figure 5-6. Installing the Rotary String Encoder........................................................................5-14

Figure 5-7 C-Arm R FRUs (Outside View)................................................................................5-15

Figure 5-8. C-Arm R FRUs (Inside View)..................................................................................5-17

Figure 5-9. Lower C-Arm FRUs.................................................................................................5-20

Figure 5-10. Top View of Tank ..................................................................................................5-22

Figure 5-11. Upper C-Arm FRUs................................................................................................5-24

Figure 5-12. Detector Assembly Mounting.................................................................................5-25

Figure 5-13. Laser Assembly......................................................................................................5-26

Figure 5-14. Rear C-Arm FRUs..................................................................................................5-27

Figure 5-15. Power Module FRUs..............................................................................................5-28

Figure 5-16. Power Control Panel FRUs ....................................................................................5-30

Figure 5-17. Operator's Console Assemblies..............................................................................5-31

Figure 5-18. Computer Assemblies.............................................................................................5-32

Figure 5-19. Aperture Assembly FRUs (QDR 4500A and SL)..................................................5-33

Figure 5-20. Aperture Assembly Removal (QDR 4500A and SL).............................................5-35

Figure 5-21. Rear Drum Assembly FRUs...................................................................................5-36

Figure 5-22. Front Drum Assembly FRUs..................................................................................5-37

Figure 5-23. Drum Outer Bearings .............................................................................................5-38

Figure 5-24. Drum Inner Bearings..............................................................................................5-39

Figure 5-25. The EMI Compliance Cable...................................................................................5-40

Figure 6-1. Scanner Motion Directions.........................................................................................6-3

Figure 6-2. Checking C-Arm Parallelism....................................................................................6-10

Figure 6-3 Tank Assembly Top view..........................................................................................6-13

Figure 6-4 Lexan Cup Screw Tightening Order..........................................................................6-14

Figure 6-5. Bladder Gasket Screws.............................................................................................6-14

Figure 6-6. Transformer Screws .................................................................................................6-15

Figure 6-7. Tank Cover Gasket...................................................................................................6-16

Figure 7-1. Guide Bearing and Rail..............................................................................................7-3

Figure 9-1. SUSQ Screen−X-Rays OFF .......................................................................................9-2

Figure 9-2. SUSQ Screen−X-Rays ON.........................................................................................9-2

Figure 9-3. SUSQ Screen Settings................................................................................................9-3

SECTION 1

INTRODUCTION

SYSTEM OVERVIEW

The Hologic QDR4500 X-ray Bone Densitometer (Figure 1-1) estimates the bone mineral content (BMC) and bone mineral density (BMD) of selected areas of the body, or of the entire skeleton. It does so using X-rays of two different energy levels. This dual-energy scheme allows soft tissue within the selected area to be subtracted out, leaving only bone to be scanned and estimated.

Note:

The patient lies face up on the table and, with the aid of a cross-hair laser, the operator positions the scanning arm over the region of interest. After entering patient data and selecting the type and size of scan desired, the operator initiates the scan with a single keystroke.

The operator is not required to select technique factors, as tube current and voltage are preselected and fixed. Since testing is performed by fan beam method rather than by flooding the area as in conventional radiography, the scanning time is a function of the dimensions of the area to be measured, the desired resolution and the desired precision.

This manual uses "QDR 4500" to refer to all models in the QDR 4500 series systems. Information presented in this manual, that applies only to a particular model, or models, will be noted as such.

BMC results are expressed in grams of calcium hydroxyapatite, and BMD is reported in grams/cm2 of the same compound.

Note:

The QDR 4500 employs a patented Automatic Internal Reference System, which continuously calibrates the machine to eliminate the effects of variations in temperature, tube flux, etc. No daily calibration is required. The daily scanning of a quality control phantom is required to provide assurance that the system is functioning correctly, and to aid in the detection of any longterm drift.

The X-ray scans produced by the QDR 4500, and displayed on the monitor, are intended only to locate anatomical sites for measurement, and to assure the operator that the machine is operating properly. They are not intended as a substitute for conventional film-based diagnostic scans.

In most cases, no additional shielding is necessary for patient, operator or room, and the QDR 4500 can be placed in any convenient non-shielded examination room. Contact your state regulatory agency for details about additional shielding requirements, if any.

1-1

Operator's Console

QDR

4500 Technical Manual

Scanner Unit

Figure 1-1. QDR



4500

X-RAY SCANNING THEORY

An X-ray source, consisting of a generator and tube in a common, shielded enclosure, is mounted beneath the patient. It generates a narrow, tightly collimated, fan shaped beam of X-rays which alternate, at power line frequency, between 100kVp and 140kVp. The source is at one end of a C-arm. At the other end, above the patient, is a crystal/solid state detector. During a scan, the Carm and table move under computer control to guide the beam over the desired scan area.

Before passing through the patient, the beam is filtered through a rotating drum, in which alternating segments have radio-opacities equivalent to tissue, bone and air. When finally intercepted by the detector, the beam contains information about the X-ray absorbing characteristics of both the patient and the calibration materials in the filter drum. An A/D converter, fed by the detector, supplies a complex digital signal to the computer, which uses that signal both to construct the screen display and as the basis for its computations of BMC and BMD.

The QDR 4500 computer algorithm is based on the principle that bone attenuates the X-ray beam differently at high and low energies. The bone mineral content of any sample point can be computed from:

Q = L - kH

where H and L are the logarithms of the sample attenuation at high (140kVp) and low (100kVp) energies, respectively, and the constant k depends on the tissue attenuation characteristics of the beam. In the QDR 4500, k is continuously measured using the “tissue” segment in the filter wheel.

1-2

Section 1 - Introduction

The program works in the following manner:

1. Load preliminary scan and obtain regions of interest from operator.

2. Estimate k as an average value of:

- L

k = [L

tissue

air

] / [H

tissue

- H

air

]

Note:

where L interposed by the filter drum, and L

The subscript "

indicates a low-energy measurement with tissue-equivalent material

tissue

, H

air

" designates the filter drum segment that is empty (i.e., contains neither

air

tissue

and H

are similarly defined.

air

bone- nor tissue-equivalent material).

3. Using this value of k, calculate Q for each point scanned using the formula given above (Q = L - kH). This array of Q values constitutes a "Q scan". Displays the Q scan.

4. Compile a histogram of the Q values. Because a large portion of the scan contains soft tissue only, this histogram will have a large peak. Choose a threshold value just above this peak, and apply that value to discriminate, point by point in the Q scan, between "bone" points (whose Q is above the threshold) and "non-bone" points (whose Q is below the threshold).

Figure 1-2. Q Scan Plot

5. Use the "non-bone" points to calculate a baseline value for each scan line. Using these

points, form a new histogram and repeat steps 4 and 5 until the results converge.

6. Smooth the segment boundaries to eliminate isolated noise-generated "bone" points.

7. Display the "bone" and "non-bone" points for operator approval.

8. Determine the constant of proportionality (d

(grams). That constant is determined by measuring how much Q shifts when boneequivalent material is interposed by the filter drum.

9. Calculate the total bone mineral values by adding up the Q values for all "bone" points

in each region of interest (e.g., each vertebra), and multiplying by d

10. Determine the bone areas by counting the number of "bone" points in each region of

interest.

11. Calculate bone mineral density as:

) that relates the Q values to actual BMC

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QDR

(

)

4500 Technical Manual

BMD = BMC / area

12. Display the calculated results and print the report.

FUNCTIONAL OVERVIEW

This section provides a block diagram of the QDR 4500 system along with a brief functional overview description of each block. A detailed functional description along with interconnection diagrams and interconnection descriptions is provided in Section 2.

AC IN

POWER

ASSEMBLY

POWER

STRIP

KEYBOARD

MOUSE

15/24V EMERGENCY

28V DC

SCSI INTERFACE

OPTICAL DISK

OPTIONAL

MODEM

(OPTIONAL)

COMMUNICATIONS CONTROLLER

Computer

PRINTER

VGA

DISPLAY

TERMINAL

PHONE

JACK

TO/FROM INSTRUMENT DISTRIBUTION (FIGURE 1.4)

TO/FROM LEFT/RIGHT PEDESTAL DRIVE (FIGURE 1.4)

TO X-RAY CONTROLLER (FIGURE 1.5)

Figure 1-3. QDR 4500 Block Diagram (Operator's Console)

1-4

TO/FROM COMMUNICATION CONTROLLER

Section 1 - Introduction

TO/ FROM C-ARM INTERFACE (FIGURE 1-5)

CONTROL

PANEL

CONTROLLER

CONTRO L PANEL

15/24V

EMERGENCY

28V DC

TO/FROM POWER MODULE

DISTRIBUTION

LEFT/RIG HT PEDESTAL

TX STEPPER

MOTOR DRIVER

TY STEPPER

MOTOR DRIVER

AR STEPPER

MOTOR DRIVER

AY STEPPER

MOTOR DRIVER

TZ DRI V E

MOTOR

CONTROLLER

TABLE IN/OUT

MOTOR AND

POSITION ENCODER

TABLE LEFT/RIGHT

MOTOR AND

POSITION ENCODER

C_ARM ROTATI ON

MOTOR AND

POSITION ENCODER

C_ARM CARRIAGE

MOTOR AND

POSITION ENCODER

PEDESTAL LEFT

MOTOR AND

POSITION ENCODER

PEDESTAL RIGHT

MOTOR AND

POSITION ENCODER

Figure 1-4. QDR 4500 Block Diagram (Scanner Unit)

1-5

QDR

4500 Technical Manual

LASER

ASSEMBLY

TO/FROM DISTRIBUTION

FROM POWER MODULE

C-ARM

INTERFACE

Figure 1-5. QDR 4500 Block Diagram (C-Arm Subsystem)

ANALOG TO

DIGITAL

CONVERTER

CONTROLLER

X_RAY

INTEGRATOR

MULTIPLEXOR

SILICON

DETECTORS

APERTURE

MOTOR AND

SENSOR

DRUM

MOTOR AND

ENCODER PICKUP

X_RAY

SOURCE

UNIT

Block Description

Computer Controls and commands all QDR 4500 hardware modules. Communications

Controller

Controls the flow of commands to and from the Scanner modules via the communications bus.

Distribution Board Provides the interconnections between the QDR 4500 Operator's Console

and the Scanner.

Control Panel Controller

Interfaces the Scanner’s Control Panel to the Operator's Console computer software.

Control Panel Provides switches (with visual indicators) for moving the Scanner’s C-

Arm and Patient Table. Also provides an Emergency Stop switch.

TZ Drive Motor Controller

Controls the motion of the Patient’s Table left and right pedestal motors based on commands from the computer software.

1-6

Section 1 - Introduction

Table Up/Down Motor and Position Encoder

TX Stepper Motor Driver

Table In/Out Motor and Position Encoder

TY Stepper Motor Driver

Table Left/Right Motor and Position Encoder

AR Stepper Motor Driver

C-Arm Rotation Motor and Position Encoder

AY Stepper Motor Driver

Raises or lowers the Patient Table and provides position monitoring.

Controls the motion of the Patient’s Table in and out motor based on commands from the computer software.

Moves the Patient Table in and out and provides position monitoring.

Controls the motion of the Patient’s Table left and right motor based on commands from the computer software.

Moves the Patient Table left and right and provides position monitoring.

Controls the motion of the C-Arm rotation motor based on commands from the computer software.

Rotates the C-Arm and provides position monitoring.

Controls the motion of the C-Arm left and right motor based on commands from the computer software.

C-Arm AY Motor and Position Encoder

C-Arm Interface Controls the Aperture and Filter Drum motors, generates timing signals

X-Ray Controller Controls the operation of the X-ray source. X-Ray Source Unit Generates the X-ray beam. Solid State Detectors Converts the X-rays into electrical signals. Integrator/

Multiplexor Analog to Digital

Converter Positioning Laser Provides a laser beam to assist in positioning the patient on the Patient

Moves the C-Arm left and right and provides position monitoring.

for the X-Ray Controller and the Data Acquisition System, and provides power to the Positioning Laser.

Integrates the signals from the Solid State Detectors and applies them to the Analog to Digital Converter.

Converts the analog signals from the Integrator/Multiplexor to a digital format.

Table.

1-7

QDR

PRODUCT SPECIFICATIONS

SPECIFICATION MODEL DEFINITION

Scanning Method: A,SL Multidetector array, Indexing table, and motorized C-arm

W,C Multidetector array, Indexing table, and Arm

Switched Pulse Dual-Energy X-ray tube, operating at 100 and

X-ray System: All

Detector System:

C,W

Scanning Sites:

SL Lumbar spine (in AP and lateral projections), proximal femur (hip)

W Lumbar spine, proximal femur (hip), and whole body

Scan Region: A,W 195cm (76.77") x 65cm (25.59")

SL 96cm (38") x 65cm (25.59")

Scatter Radiation:

All

Leakage Radiation:

External Shielding Requirement:

Calibration: All System Weight: Scanner Console

(installed)

(shipping)

All

All Contact state regulatory agency.

SL 365kg 800lb

W 310kg 680lb

SL 660kg 1450lb

W 622kg 1370lb

140kV, 5mA avg. at 50% duty cycle, 2.5mA avg. at 25% duty cycle, 30s maximum, Tungsten target

216 multichannel detector consisting of CdWO4 scintillators

coupled to Silicon diodes 128 multichannel detector consisting of CdWO4 scintillators coupled to Silicon diodes 64 multichannel detector consisting of CdWO4 scintillators coupled to Silicon diodes Lumbar spine (in AP and lateral projections), proximal femur (hip),

and whole body

C Lumbar spine, proximal femur (hip)

C 96cm (38") x 51cm (20")

Less than 10µGy/h (1mrad/h) at 2m (79 in.) from the center of the X-ray beam for all scans except images, which is less than 10µGy/h (1mrad/h) at 3.5m (138 in.) from the center of the X-ray beam.

The QDR-4500 meets the requirements of 21 CFR 1020.30(k) for leakage from the X-ray source

Self Calibrating using HOLOGIC Automatic Internal Reference System. Operator calibration NOT required.

A 365kg 800lb

C 295kg 650lb

A 660kg 1450lb

C 610kg 1340lb

4500 Technical Manual

68kg 150lb

System

1-8

Section 1 - Introduction

SPECIFICATION MODEL DEFINITION

Operating

Temperature:

All 15

Humidity: All 20 - 80% relative Humidity, non-condensing

Footprint: Length Width Height

C-arm not rotated, table not

A 2.02 79.5 1.40 55 1.42 56

extended

- 32o C (60o - 90o F)

m inches m inches m inches

C-arm rotated, table extended

C-arm not rotated C-arm rotated table extended table not

extended

A 3.02 119 1.50 59 1.42 56

SL 2.02 79.5 1.40 55 1.42 56 SL 2.02 79.5 1.50 59 1.42 56

W 3.02 119 1.50 59 1.42 56 W 2.02 79.5 1.22 48 1.42 56

C 2.02 79.5 1.40 55 1.42 56

Average Heat Load:

Patient Table Height:

Positioning Laser: All

X-ray Collimation:

Lateral Tracking:

ALL 1000w (3400 BTU/hr)

A,SL Adjustable, 71cm (28") from floor when scanning in AP mode W,C 71cm (28”)

Laser Diode (<1mW) cross hair, with emergency mechanical

shutter A,SL Selectable by scan type W,C 1.0mm slit

A,SL

Exam table is capable of moving +/-2.54cm (1.0") in the x-axis

from center location with scan arm in lateral position. C,W N/A

Leakage Current: All Normal <75µA Single Fault <400µA Resolution:

A/SL 1 line pair/mm (approximately 0.5mm)

C/W 0.5 line pair/mm (approximately 1.0mm)

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QDR

4500 Technical Manual

BMD Precision:

SCAN TIME DOSE

EXAM MODEL (seconds) in vivo PRECISION mGy mrad

AP Spine Array All 60 1.0% 0.20 20.0 AP Spine Fast All 30 1.5% 0.10 10.0 AP Spine High Definition A,SL 120 1.0% 0.20 20.0 AP Spine Turbo A,SL 10 2.0% 0.07 7.0

W,C 15 2.0% 0.05 5.0

Forearm A,SL 30 1.0% 0.05 5.0

W,C 30 1.0% 0.10 10.0 Hip Array All 60 1.0% 0.20 20.0 Hip Fast All 30 1.5% 0.10 10.0 Hip High Definition A,SL 120 1.0% 0.20 20.0 Hip Turbo A,SL 10 2.0% 0.07 7.0

W,C 15 2.0% 0.05 5.0 Lateral Spine Array A,SL 240 1.0% 0.70 70.0 Lateral Spine Fast A,SL 120 1.0% 0.35 35.0 Lateral Spine High Def. A,SL 240 1.0% 0.70 70.0 Whole Body A 180 1.0% 0.01 1.0

W 407 1.0% 0.015 1.5

Duty Cycle:

SL,W,C 50% for all Scan Modes

50% for all scan modes except Whole Body 100% for Whole Body scans

Leakage Technique Factors

The leakage technique factors for all models of QDR 4500’s are the same. It is the maximum continuous current at the maximum peak potential. This is X-ray mode #3. Peak potential 140/100kVp. (dual energy), current 10mA peak 25% duty cycle or 2.5mA average.

Minimum Beam Filtration

The minimum filtration permanently in the beam is 3.7mm Al equivalent @80kV.

1-10

Section 1 - Introduction

Measured Half Value Layer (HVL) At Different Operating Potentials

Measured operating potential Measured Half Value Layer

QDR4500A/SL

80kV 3.7mm Al equivalent 100kV 4.7mm Al equivalent 140kV 7.2mm Al equivalent

QDR4500C/W

80kV 3.7mm Al equivalent 100kV 5.0mm Al equivalent 140kV 6.5mm Al equivalent

Line Voltage and Maximum Line Current

Power Requirements:

All

100VAC 16A 50/60Hz, Max apparent resistance = 0.32 ohm 120VAC 14A 50/60Hz, Max apparent resistance = 0.32 ohm 230VAC 8A 50/60Hz, Max apparent resistance = 1.28 ohm

Technique Factors for Maximum Line Current

Peak Potential 140kVp Tube Current 10mA peak, 50% duty factor or 5mA average.

Maximum Deviation

The maximum deviation from the preindication given by labeled technique factor control settings or indicators are as follows:

Peak Potential: +/- 15% Current: +/- 40% Time : +/- 10%

Measurement Criteria for Technique Factors

The measurement criteria of the technique factors is as follows:

Peak Potential: The voltage peak is measured with an oscilloscope. Voltage is a square pulse.

Peak is defined as the peak voltage of the 4 millisecond pulse shape, not counting any initial overshoot.

Current: Current is measured with an oscilloscope on the last millisecond of the 4

millisecond pulse.

Time: Time of each pulse is measured with an oscilloscope and defined as the time

between 50% rise and fall times of the peak potential pulse. Time of the scan is measured by counting the number of AC line pulses from the start to the end. X-ray pulses are synchronous with the AC line.

1-11

SECTION 2

FUNCTIONAL DESCRIPTION

This section provides a detailed functional description along with interconnection diagrams and descriptions of the Hologic QDR 4500. Refer to Section 1 for a block diagram and a brief functional description of each block.

COMPUTER

The QDR 4500 Scanner interfaces to an ISA Bus computer to control table and C-arm movement and X-ray generation, perform all necessary calculations, and manage patient and QC database information.

The computer is a Pentium-based (or higher) PC compatible that comes equipped with 3.5-inch floppy disk and hard disk drives, keyboard, color monitor, and an optional Iomega 1GB JAZ drive. For details pertaining to the computer and its associated components, please refer to the documentation shipped with each unit.

COMMUNICATIONS CONTROLLER BOARD

The Communications Controller board handles all the communications between the Computer and the Scanner’s C-Arm and Table assemblies. The board resides in one of the computer internal slots and interfaces with the computer via the computer's I/O bus. It connects to the Scanner’s Distribution board through a 50 conductor ribbon cable. This cable contains two independent communications links (one asynchronous and one synchronous) and additional system control signals. Each signal requires a pair of conductors for differential (RS422) noise immunity.

The asynchronous communications link communicates with the Motor Controller boards (TX, TY, AY and AR), the TZ Drive board, the C-Arm Interface board, and the Control Panel Controller board. The synchronous communications link communicates with the Data Acquisition System (DAS).

Interface Connections

Table 2-1 describes the interconnections between the Communications Controller board and the Distribution board. The table also identifies the interconnection connector and pin assignments.

Figure 2-1 shows the interconnections between the Communications Controller board and the Distribution board.

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QDR

4500 Technical Manual

Table 2-1. Communications Controller Board/Distribution Board

Interconnection Descriptions

Signal Pair Description

ATD+ ATD-

STD+ STD-

STCLK+ STCLK-

STFRM+ STFRM-

ARD+ ARD-

SRD+ SRD-

SRCLK+ SRCLK-

SRFRM+ SRFRM-

EMERGENCY_IN+ EMERGENCY_IN-

ZEROX+ ZEROX-

INTEGRATE+ INTERGATE-

SYSRESET+ SYSRESET-

EMERGENCY+ EMERGENCY-

Asynchronous data to the Scanner.

Synchronous data to the Scanner. JP1-28

Synchronous data clock from Communications Contr oller board to Distribution board. Synchronizes data to the Scanner.

Synchronous data frame from Communications Controller board to Distribution board.

Asynchronous Data from the Scanner. JP1-8

Synchronous Data from the Scanner. JP1-34

Synchronous data clock from Communications Contr oller board to Distribution board. Synchronizes data from the Scanner.

Synchronous data frame from Distribution board to Communications Controll er board.

Signals an emergency condition. Generated by the C-Arm Interface board.

AC line zero-crossing signal used for system wide synchronization. Generated by the C-Arm Interface board.

Synchronous signal for Detector Integrate period. Generated by the C-Arm Interface board.

Resets the Scanner controllers. JP1-20

Removes power from the Scanner’s motor drivers and the X-ray system

JP1-2 JP1-27

JP1-4 JP1-5

JP1-30

JP1-31 JP1-7

JJP1-33

JP1-10 JP1-11

JP1-36

JP1-37 JP1-13

JP1-14 JP1-39

JP1-40 JP1-16

JP1-17 JP1-42

JP1-45 JP1-49

JP1-25

Dist

JP10-3 JP10-4

JP10-6 JP10-7

JP10-9 JP10-10

JP10-12 JP10-13

JP10-15 JP10-16

JP10-18 JP10-19

JP10-21 JP10-22

JP10-24 JP10-25

JP10-27 JP10-28

JP10-30 JP10-31

JP10-33 JP10-34

JP10-39 JP10-40

JP10-48 JP10-49

Note:

2-2

1. CC = Communications Controller board.

2. Dist = Distribution board.

Section 2 - Functional Description

ATD+, ATDSTD+, STDSTCLK+, STCLKSTFRM+, STFRMARD+, ARD-

COMMUNICATIONS

CONTROLLER

BOARD

SRD+, SRDSRCLK+, SRCLKSRFRM+, SRFRMEMERGENCY_IN+, EMERGENCY_INZEROX+, ZEROXINTEGRATE+, INTEGRATESYSRESET+, SYSRESETEMERGENCY+, EMERGENCY-

DISTRIBUTION

BOARD

Figure 2-1. Communications Controller Board/Distribution Board

Interconnection Diagram

DISTRIBUTION BOARD

The Distribution board provides interconnections between the QDR 4500 Operator's Console and the Scanner. It passes several signal and power lines from the Operator's Console directly to the C-Arm Interface module. It also provides buffering and individual drivers and receivers for various signal lines to and from individual Scanner modules and the Communications Controller. The Distribution board is located in the Electronics Tray in the base of the Scanner.

Three cables connect the Operator's Console to the Distribution board. One cable connects the communications buss to the Communications Controller located in the Operator's Console computer. Two cables connect to the Operator's Console Power Module. These two cables connect power to the Distribution board and connect the X-Ray On and Emergency signal lines to the Power Module.

Eight cables connect the Distribution board to the various Scanner boards. Four cables connect to the four Motor Controller boards (Table X, Table Y, Arm R, and Arm Y). Two (one signal and one power) connect to the C-Arm Interface board. One connects to the TZ Drive board. And, one connects to the Scanner's Control Panel Controller board.

The Distribution board has provision for three jumpers that can be installed to override the EMERGENCY signal lines when trouble-shooting.

Power

The Distribution board receives +28, +24 and +/-15VDC from the Operator's Console Power Module. The +28VDC is applied through four individual circuit breakers to the Table X, Table Y, Arm R, and Arm Y Motor Controller boards. The +24 and +/-15VDC are passed to the CArm Interface board. +24VDC is also applied through a circuit breaker to the Table Z Drive board. It is also reduced to +7 and + 5VDC by regulators to power op-amplifiers and analog switches located on this board. The + 7VDC is passed to the Table Z Drive and Control Panel Controller boards. The + 5VDC powers the digital section of the Distribution board. The +28 and +24VDC power supplies are not closely regulated and their outputs may range from +24V to + 35V under normal conditions.

2-3

Note:

QDR

+7VDC may measure anywhere from +6.25VDC to +7.25VDC. This is true everywhere

4500 Technical Manual

+7VDC is shown in this manual.

Six green LEDs indicate the status of the +28, +24, +15, -15, +7 and +5VDC (ON indicates the respective voltage is present). Five red LEDs indicate the status of the five circuit breakers applying voltage to the motor drivers/controller. ON indicates the circuit breaker has detected an over-current condition.

Interface Connections

Figure 2-2 shows boards that connect to the Distribution board.

OPERATOR’S

CONSOLE

COMPUTER

COMMUNICATIONS

CONTROLLER

BOARD

OPERATOR’S

CONSOLE

POWER MODULE

+24 VDC, +/-15VDC,

EMERGENCY

SIGNAL L INES

DISTRIBUTION

BOARD

INSTRUMENT

C-ARM

INTERFACE

BOARD

CONTROL P ANE L

CONTROLLER

BOARD

DRIVE

BOARD

TX MOTOR

CONTROLLER

BOARD

TY MOTOR

CONTROLLER

BOARD

+28 VDC

Figure 2-2. Distribution Board High Level Interconnection Diagram

2-4

AR MOTOR

CONTROLLER

BOARD

AY MOTOR

CONTROLLER

BOARD

Section 2 - Functional Description

MOTOR CONTROLLER BOARD

The Motor Controller board is a microprocessor controlled power driver circuit for use with a two coil bipolar stepper motor. It receives high level commands through the Distribution Board from the host computer, and applies 28 volt pulses to the stepper motor windings. The QDR 4500 uses four identical Motor Controller boards to control and drive the Table X (Table In/Out), Table Y (Table Left/Right), C-Arm Rotate, and C-Arm Y (C-Arm Left/Right) stepper motors. The motor windings are driven by two integrated H-bridges. These integrated circuits provide internal level conversion and power limiting. Their logic level control inputs are driven from a stepper motor control microcircuit that receives commands from the microprocessor. The control circuit senses the current in the motor windings and adjusts the duty cycle of the applied voltage in such a way as to limit the maximum motor current. The maximum value is determined by an 8-bit control word at a Digital to Analog Converter.

Each Motor Controller board monitors the position of its respective mechanism using a signal received from an associated Position Encoder connected to the mechanism. The Position Encoder is a precision potentiometer that divides a +/-3V reference source into a sense amplifier in proportion to the position of the mechanism driven by the motor. The sense amplifier output is converted to digital code that provides position feedback to the microprocessor.

The Motor Controller boards receive movement commands from the QDR 4500 computer via the communications bus. Each Motor Controller board contains an ID switch and four status indicators (LEDs). The ID switch is a 16-position rotary encoded switch (SW1) that is read during system initialization to determine the Motor Controller board's address for communicating with the QDR 4500 computer. ID switch settings for the four Motor Controller boards are as follows:

Table X drive 4 Table Y drive 5 C-Arm Rotate drive 6 C-Arm Y drive 7

The four red status LEDs provide visual indications of motor drive power on, Stepper CPU active, motor drive direction, and motor step pulses.

The Motor Controller board also has provision (JP2) for connecting limit switches to inhibit motor operation when the mechanism goes beyond established mechanical limits. This feature is not used in the QDR 4500 and therefore no cable is connected to JP2.

Power

Power input to the Motor Controller board is +28VDC. This voltage provides the motor drive power and is converted down to +5VDC for use by logic circuits on the board. The +5VDC is also converted to -5VDC. Two green LEDs provide visual indication of the power present on the Motor Controller board.

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QDR

4500 Technical Manual

Interface Connections

Figure 2-3 shows the interconnections between the Distribution board, the Motor Controller boards, the Stepper Motors, and the Position Encoders. Table 2-1 describes the interconnections between the Distribution board and the Motor Controller. Table 2-3 describes the interconnections between each Motor Controller and its respective stepper motor and position encoder. The tables also identify the interconnection connector and pin assignments.

To/From

(

)

Distribution Board

ARD+, ARDATD+, ATDSYSRESET+, SYSRESET+28V 28V_RET

MOTOR

CONTROLLER



(

)



(

)



(

)



+REF (

)



-REF

STEPPER

MOTOR

POSITION

ENCODER

Figure 2-3. Distribution Board/Motor Controller Board

Interconnection Diagram

Table 2-2. Distribution Board/Motor Controller Board

Interconnection Descriptions

Signal Description

ARD+

Asynchronous Receive Data. JP7 JP5 J P8 JP11 11

ARDATD+

Asynchronous Transmit Data. JP7 JP5 JP8 JP11 14

ATDSYSRST+

SYSRST28V

28V_RET

System Reset. Resets the Motor Controller board.

DC power for the Motor Controller board.

TableXTableYC-Arm

JP7 JP5 JP8 JP11 17

JP7 JP5 JP8 JP11 2,3,4,5

C-ArmYPin(s)

Rotate

1,6,7,8

2-6

Section 2 - Functional Description

Table 2-3. Motor Controller Board/Stepper Motor and Position Encoder

Interconnection Descriptions

Signal Description Pin

(No label) Motor drive signals (4). JP5-1 - JP5-4 +REF Precision positive voltage to position potentiometer. JP3-1 (No label) Position encoder wiper return voltage. JP3-3

-REF Precision negative voltage to position potentiometer. JP3-5

TZ DRIVE BOARD

The TZ Drive Board is a microprocessor controlled power driver circuit for the two pedestal motors which raise and lower the patient table in the QDR 4500A and SL. This board is located in the electronics tray in the bottom of the Scanner base assembly.

The TZ Drive board communicates with the communications controller, via the Distribution board, to drive the pedestal motors under computer control. Manual raising of the pedestal may be required in case of an emergency. In this case, manual control is provided through the Table switch of the Scanner’s Operator Control Panel.

The TZ Drive board monitors the position of each pedestal using signals received from an associated Position Encoder connected to the respective pedestal.

Service Switches

The TZ Drive board contains four service switches used during replacement of a defective pedestal or Position Encoder. Table 2-4 describes these switches and their respective functions.

CAUTION:

The TZ drive motors are designed to run at a 5% duty cycle. If the motors overheat, the built-in thermal cutouts may trip and cause the motors to stop functioning. If this happens, you must wait about 20 minutes before functionality is restored. See the heading

Unable to position device within specified tolerance…

on page 6-45.

Table 2-4. TZ Drive Service Switches

Switch Function

Mode (Normal/Service)

Direction (Up/Down) When the TZ drive is in Service mode, determines the direction of pedestal

Left When the TZ drive is in Service mode, moves the left pedestal in the

Determines whether the TZ Drive is in Normal or Service operation.

movement (not active in normal mode).

direction specified by the Direction switch (not active in normal mode).

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QDR

4500 Technical Manual

Right When the TZ drive is in Service mode, moves the right pedestal in the

direction specified by the Direction switch (not active in normal mode).

Reset

Resets the board after manual operation.

The TZ Drive board must be

reset after any manual operation.

Power

Power input to the TZ Drive board is +24VDC from the Distribution board and 240VAC from the Operator's Console Power Module. +24VDC powers circuitry located on this board and is reduced to +5VDC. +5VDC is converted to -5VDC and +/-3VDC. The +5and -5VDC powers logic circuitry on this board, while the +/- 3VDC provides the reference voltage for the position sensors. Two green LEDs provide visual indication of the +24 and +5VDC status (ON indicates the respective voltage is present).

The 240VAC power is connected through control relays to the pedestal motors.

Interface Connections

Figure 2-4 shows the interconnections between the Distribution board, the TZ Drive Board, the Pedestal Motors, and the Pedestal Position Encoders. Table 2-5 describes the interconnections between the Distribution board and the TZ Drive Board. Table 2-6 describes the line voltage (240VAC, line to line) between the Operator's Console Power Module and the TZ Drive Board. Table 2-7 describes the interconnections between the TZ Drive Board and the two pedestal motors and their respective position encoders. The tables also identify the interconnection connector and pin assignments.

2-8

+ 220 hidden pages