Lunar Prodigy

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PRODIGY

Service Manual

Part Number: LUN7396 Revision: C

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This document contains confidential or proprietary information of GE-Lunar Corp. neither the

document nor the information is to be reproduced, distributed, used or disclosed, either in whole or

in part, except as specifically authorized by GE-Lunar Corp.

GE-LUNAR Corporation makes no warranty of any kind with regard to this material, and shall not be

held liable for errors contained herein or for incidental or consequential damages in connection

with the furnishings or use of this manual.

Read through this manual thoroughly before attempting to service any components. Unauthorized

service may void system warranties or service contracts. Consult the GE-LUNAR Customer

Support Department prior to attempting any servicing:

608-828--2663

608-826-7107 (Fax)

g

_{is a registered trademark of General Electric Company.}

PRODIGY® is a trademark of GE-LUNAR Corporation.

Windows NT® is a trademark of Microsoft Corporation

Copyright© 2000 by GE-LUNAR Corporation.

Madison, Wisconsin. All rights reserved.

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READ THIS FIRST

Using This Manual:

A person who will be performing service work on the PRODIGY should use this manual in the

following manner:

Read the Safety and Overview Chapters to familiarize yourself with the scanner as a whole and

with the general function of the circuit boards.

Chapter 3 should be understood completely as it explains the Diagnostics Software (built in –

requires a password for access).

The Chapter 4 and Chapter 5 contain common procedures and troubleshooting information and

can be read as needed, but are good sources of information.

When a problem arises, Chapter 4 should be referenced. Check the table of contents for Chapter 4

to see if the problem being experienced is described. If so, refer to the appropriate page. If not, try

to generalize the problem (e.g. the Detector is repeatedly running into the front of the scanner and

reversing and then running back into the front of the scanner. This is a mechanical problem in

general, specifically with Transverse Mechanics, check that subsection of Chapter 4 for the

subsystem experiencing the fault.

This manual commonly references other Sections and pages of the manual as needed, so often

procedures in the Chapter 5 Appendix are referred to as ways to solve problems described in

Chapter 4. Information Requested By GE-LUNAR:

When requesting assistance from GE-LUNAR, please provide the following information:

System Number (DF+xxxxx)

Institution or Doctor's name

Location

Complete list of symptoms

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In addition to the information above, an Error Log printout and QA’s and QA history or other failing

diagnostic test printout (Alignment Test etc.) will also help to improve the accuracy of our

diagnosis:

For problems with specific patient scans, it is recommended that you copy the scan files to

diskette, and send it, with a description of the problem, to the Applications Department at GE -

LUNAR.

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Chapter 1:Safety

This chapter highlights safety devices and features a Service

Engineer should know before servicing a PRODIGY system.

Chapter Contents:

1.0 General Safety . . . 1-15 1.1 Symbols and labels found on the PRODIGY . . . 1-15 1.1.1 External Symbols. . . 1-15 1.1.2 Internal Symbols . . . 1-16 1.1.3 Labels . . . 1-16 1.2 Emergency Stop Button . . . 1-19 1.3 Laser Exposure . . . 1-20 1.4 Shutter Indicator . . . 1-21 1.5 Cautions, Warnings, and Notes . . . 1-21 1.5.1 Caution Statements . . . 1-21 1.5.2 Warning Statements . . . 1-22 1.5.3 Note Statements . . . 1-22 1.6 Safety Concerns . . . 1-22 1.6.1 Pinch points . . . 1-22 1.6.2 Laser safety . . . 1-23 1.6.3 Radiation safety. . . 1-24 1.6.4 Scatter Radiation . . . 1-24 1.7 Controlling Computer and Accessories . . . 1-26 1.7.1 Electrical Safety. . . 1-26 1.7.3 Peripheral Configurations . . . 1-26 1.7.4 Standard room configuration (system no. DF+12000 and

greater)1-26

1.7.5 Small room configuration (system no. DF+12000 and higher) 1-27 1.7.6 Scanner power output configuration (system no. DF+11999 and

lower) . . . 1-27 1.7.7 Wall outlet configuration (system no. DF+11999 and lower) . . 1-27 Figure 1-1. The PRODIGY Display Panel . . . 1-19 Figure 1-2. Laser Warning Label (U.S. systems only) . . . 1-20 Figure 1-4. Laser Warning Label (International systems only) . . . 1-20 Figure 1-5. Source (x-rays) off - Shutter closed (green) . . . 1-21

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Figure 1-6. Source (x-rays) on - Shutter open (yellow). . . 1-21 Figure 1-7. Potential Pinch Points on the PRODIGY . . . 1-23 Figure 1-8. PRODIGY Iso-Dose Diagram . . . 1-25

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1.0 General Safety

• DO NOT attempt to service the PRODIGY without first reading this manual.

• DO NOT attempt any repairs without prior instructions from authorized LUNAR personnel.

• In order to maintain electrical safety and electromagnetic compatibility, the Lunar PRODIGY is only to be connected to a computer, printer, and peripherals that are certified to be compliant with IEC 950/EN 60950 Safety of information technology equipment, including electrical business equipment and IEC 601-1-2 Medical electrical equipment, Part 1: General requirements for safety, 2. Collateral Standard: Electromagnetic compatibility - Requirements and tests.Emergency Stop Button

1.1 Symbols and labels found on the PRODIGY

1.1.1 External Symbols

• The following symbols are found on the PRODIGY, in the Operators manual, and in the Service Manual.

Attention: contains important safety information such as the location of a pinch point.

Emergency Stop Button: shows the location of the emergency stop button.

Power On: shows the location of the Power On indicator and the switch position for Power On.

Power Off: shows the switch position for Power Off.

Laser On: shows the location of the Laser On indicator. It is found only on systems delivered internationally.

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Shutter Open: shows the location of the Shutter Open indicator.

X-ray On: shows the location of the X-Ray On indicator.

Type B Equipment: shows that the scanner has Type B protection against electrical shock.

1.1.2 Internal Symbols

• The following symbols are found inside the PRODIGY, and in the Service Manual.

Protective Earth: shows the location of a Protective Earth Terminal.

Functional Earth: shows the location of a Functional Earth Terminal.

1.1.3 Labels

• The following labels are found on the PRODIGY Scanner.

Laser Caution Label: Shows that the scanner uses a Class II laser. This label is not found on systems shipped to Canada.

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Tube Head Assembly Label (system number DF+12000 and greater): This label gives tube head assembly and x-ray source characteristics

information. It is located on the tube head assembly and the foot panel of the scanner.

Tube Head Assembly Label (system number DF+11999 and lower): This label gives tube head assembly and x-ray source characteristics

information. It is located on the tube head assembly and the foot panel of the scanner.

A definition of each symbol on this label follows:

Inherent Filtration

Tube Insert

X-ray Source

Focal Point

System Label (system number DF+12000 and greater): This label gives system input power requirements and compliance information. It is located on the foot panel of scanners. The CE mark shows compliance with UL/CSA and the Medical Device Directive 93/42/EEC.

System Label (system number DF+11999 and lower): This label gives system input power requirements and compliance information. It is located on the foot panel of scanners. The CE mark shows compliance with UL/CSA and the Medical Device Directive 93/42/EEC.

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High Voltage Power Supply: This label gives high voltage power supply (x-ray generator) information. It is located on the positive and negative power supplies, and foot panel of the scanner.

X-ray Controller: This label shows x-ray controller compliance. It is located on the foot panel of the scanner.

Collimator Assembly: This label gives

collimator assembly information. It is located on the collimator and foot panel of the scanner.

Warning Label and Radiation Symbol: The Warning label shows that the system uses ionizing radiation. It is found only on systems delivered in the United States. Always obey instructions for safe operation.

Radiation Label: This label shows that the system uses ionizing radiation.

Grounding Reliability Label: This label states that grounding reliability can only be maintained when using a “Hospital Grade” or “Hospital Only” receptacle. It is only found on systems delivered in the United States.

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1.2 Emergency Stop Button

• The Emergency Stop Button is a round red button located on the scanner display panel (see Figure 1-1). When pressed, power is removed from the X-ray tube head, the laser, and the shutter is closed. Power is also removed from the scan arm motors, allowing the operator/patient to push the scan arm out of the way.

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1.3 Laser Exposure

• The PRODIGY is equipped with a Class II Laser device. This laser is used for patient positioning. A Class II rating indicates a low power visible laser that is not normally hazardous to eyesight but has the potential to be hazardous if viewed directly for an extended period of time. Because of this potential hazard, DO NOT stare directly into the beam while the laser is in operation, and DO NOT allow the beam to shine directly into the patients' eyes. No specific eye protection is required with a Class II laser.

• A amber laser-on indicator, located on the front of the scan arm, is lit when the laser is on. The program activates the laser during positioning for an image acquisition. The program then turns off the laser when you begin the scan. The emergency stop button will turn off the laser.

• There is a caution label (Figure 1.2) on the scan arm near the Display Panel.

Figure 1-2. Laser Warning Label (U.S. systems only)

Figure 1-3. Laser Warning Label (Canadian Systems only)

Figure 1-4. Laser Warning Label (International systems only)

Note: DO NOT STARE INTO THE BEAM while the laser is

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1.4 Shutter Indicator

• This symbol is used to indicate an open-shutter condition in accordance with the safety standards established by the International

Electrotechnical Commission (IEC).

Figure 1-5. Source (x-rays) off - Shutter closed (green)

Figure 1-6. Source (x-rays) on - Shutter open (yellow)

• This symbol appears near the yellow X-ray shutter-open indicator light. The X-ray shutter-open indicator light is located on the Display Panel on the scan arm near the front.

Note: When the x-ray on / shutter open symbol appears in literature

associated with the PRODIGY scanner, it will be used to indicate that the procedure being described results in an open-shutter condition. During these times personnel should exercise caution to avoid excessive exposure to the X-rays.

1.5 Cautions, Warnings, and Notes

• This manual contains warning and caution statements wherever

appropriate for your safety. The warnings and cautions used throughout the manual are based on the safety standards established by the International Electrotechnical Commission (IEC). In addition, the manual uses notes to attract the reader's attention to important information.

1.5.1 Caution Statements

A caution statement reflects a condition that, if not avoided, could cause

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1.5.2 Warning Statements

A warning statement reflects a potentially hazardous condition that, if not avoided, could result in serious injury.

1.5.3 Note Statements

Note: This symbol turns the reader's attention to important

information which may otherwise be overlooked.

1.6 Safety Concerns

1.6.1 Pinch points

The Warning label below identifies the location of possible pinch points

Because the PRODIGY Densitometer contains moving parts, there are places on the scanner where there is a danger of pinching. Operators should be aware of these pinch points to avoid injury to the patient or themselves. When the scanner arm is in motion, make sure possible pinch point locations are clear at all times. Labels applied at the LUNAR factory indicate the location of the pinch points. The pinch points and their labels are shown in the figure 1-7.

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Figure 1-7. Potential Pinch Points on the PRODIGY

Do not touch the AC Surge Suppressor (located on the AC terminal block) it may be hot.

Do not electrically connect the isolation transformer bolt head to ground, doing this will short out the transformer

Scan table isolated outlet strip must be appropriately connected.

1.6.2 Laser safety

DO NOT STARE INTO THE LASER BEAM

during patient positioning and Quality Assurance procedures.

The label that follows is located on the scanner arm and shows the location of the laser aperture.

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1.6.3 Radiation safety

X-ray exposure: The system makes radiation when electric voltage is supplied to, and current flows through, the x-ray tube. During a measurement, the shutter opens to let a beam of radiation pass through the scanner table and patient. The radiation field at the table top is 19.2 mm x 3.3 mm. Lead oxide shielding surrounds the x-ray tube insert inside the tube housing assembly and reduces radiation levels around the scanner table. Skin entrance dose: Table 1 of the PRODIGY Operators Safety and Specifications manual shows irradiation times and skin entrance doses.

1.6.4 Scatter Radiation

• There is some scatter radiation from the PRODIGY when it is running. Figure 1-8 shows the radiation dosages while the scanner is running at 3.00 mA at certain distances.

• These dosages are relatively insignificant as the allowed yearly dosage for a person working with radiation emitting equipment is 5000 mRem. Radiation however should be avoided when possible.

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1.7 Controlling Computer and Accessories

1.7.1 Electrical Safety

IEC and UL/CSA certification

IEC: To maintain electrical safety, all computer equipment and accessories connected to the scanner must meet all IEC requirements for safety, such as IEC 950, "Safety of information technology equipment, including electrical business equipment," and IEC 801-5, "EMC Surge Immunity Requirements." The computer and all accessories must have the CE label.

UL/CSA: To maintain electrical safety, all computer equipment and

accessories connected to the scanner must have safety agency approvals for UL/CSA.

1.7.2 Electromagnetic interference

Although the scanner meets safety standards regarding electromagnetic interference (EN60601-1-2), you may still experience a loss of performance under extreme electromagnetic conditions. Maximize the distance between the scanner and other equipment, and use a dedicated power line, to avoid interference to and from the scanner.

1.7.3 Peripheral Configurations

The correct connection of the computer and all peripherals is necessary to maintain electrical safety. The signal cable of the scanner is intended only for connection to an approved computer. Call LUNAR Support or your LUNAR distributor before adding peripherals.

Note: The scanner's output power strip can be used to supply the

Host PC with isolated power. If it is to be used the following conditions must be met. If the conditions cannot be met, the scanner's output power strip cannot be used.

Note: See also Peripheral Block Diagrams - Section 2.2.3

1.7.4 Standard room configuration (system no. DF+12000 and

greater)

The computer, peripherals, and all other equipment must be located more than 1.83 m from the scanner. Use an outlet strip to power the computer and all peripherals. The outlet strip must be mounted off the floor so that it does not touch other equipment. If your outlet strip was provided by LUNAR, it has a maximum output of 15A, 120VAC. Only system-related equipment should

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A modem and/or network connection can be made at any time if you are using the standard room configuration.

1.7.5 Small room configuration (system no. DF+12000 and higher)

You must power the computer, peripherals, and all other equipment with an isolating transformer if the room is too small to maintain at least 1.83 m of separation between the scanner and all other equipment.

The isolation transformer supplied by LUNAR has a maximum output of 400/ 500VA. Only system-related equipment should be powered by the isolation transformer. Failure to use an isolation transformer can cause leakage currents in excess of 100 microamperes.

A modem and/or network connection can only be made in the small room configuration if all exposed metal surfaces of the computer and peripherals are out of the patient environment.

1.7.6 Scanner power output configuration (system no. DF+11999

and lower)

LUNAR recommends that you use scanner power output to provide isolated power to the computer and all peripherals. The power strip must be mounted off the floor such that it does not touch other equipment. The computer and ALL peripherals must be powered by the scanner. All other equipment must not be powered by the scanner and must be located more than 1.83 m from the scanner. Failure to use scanner power output can cause leakage currents in excess of 100 microamperes.

If a network and/or modem connection is needed, refer to the wall outlet configuration.

1.7.7 Wall outlet configuration (system no. DF+11999 and lower)

As an option to scanner power output, a wall outlet can be used to power the computer and peripherals. Isolated power from the scanner must not be used to power any equipment if a wall outlet is used. All exposed metal surfaces of the computer, peripherals, and other equipment must be located more than 1.83 m from the scanner.

A network and/or modem connection can be made to the computer if power is supplied from a wall outlet as described above.

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Chapter 1:System Overview

This chapter provides an overview of the PRODIGY system.

• In addition the chapter contains a brief discussion of major

sub-systems and illustrations of the PRODIGY power system. • This Chapter contains the PRODIGY Block Diagrams

2.0 PRODIGY System . . . 1-33 2.0.1 PRODIGY Electronics . . . 1-33 2.1 Electronics . . . 1-35 2.1.1 Cautions . . . 1-35 2.1.2 Electronics Pan . . . 1-35 2.1.3 Scan Arm. . . 1-36 2.1.4 Power specifications . . . 1-36 2.2 PRODIGY Block Diagrams . . . 1-38

2.2.1 PRODIGY I (System numbers DF+11999 and lower) Power Distribution Block Diagram (AC entrance) . . . 1-38 2.2.2 PRODIGY System Block Diagram PRODIGY I System Block Diagram . . . 1-39 2.2.3 PRODIGY I Peripheral Configuration Block Diagrams . . . 1-40 2.2.4 PRODIGY II System / Power Block Diagram . . . 1-41 2.3 PRODIGY Fusing . . . 1-42 2.4 PRODIGY I (system numbers DF+11999 and lower) Single Board Controller . . . 1-43

2.4.1 SBC Functions . . . 1-43 2.4.2 SBC Reset. . . 1-43 2.4.3 SBC / Host PC Interface . . . 1-44 2.5 PRODIGY II Combined Single Board Controller (cSBC) (systems DF+12000 and greater) . . . 1-45

2.5.1 cSBC System Architecture . . . 1-45 2.5.2 cSBC Functions. . . 1-46 2.5.3 TRANS / LONG MOTOR Control and Status . . . 1-50 2.5.4 AGS ROLL . . . 1-51 2.5.5 AGS DAC . . . 1-51 2.5.6 SCANNER RESET . . . 1-52 2.5.7 GE-LUNAR Model 7861 X-ray Generator Errors. . . 1-53 2.5.8 DC FAIL . . . 1-54

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2.5.9 DCA / AGS / BIAS DAC's . . . 1-54 2.5.10 KV/mA DAC . . . 1-55 2.5.11 ARC/FIL DAC. . . 1-55 2.5.12 PEAK DAC. . . 1-55 2.5.13 MAX PLD Peripherals . . . 1-55 2.5.14 Interrupts . . . 1-56 2.5.15 MASTER RESET . . . 1-56 2.5.16 SUICIDE RESET . . . 1-57 2.5.17 MISC OUT . . . 1-57 2.5.18 MISC IN . . . 1-57 2.5.19 Stepper Motor Control . . . 1-58 2.5.20 OMI Input . . . 1-59 2.5.21 Patient Positioners . . . 1-59 2.5.22 Limit Switches . . . 1-59 2.5.23 X-ray Source Control / Mechanical Interlocks . . . 1-59 2.5.24 Shutter / Collimator Drive. . . 1-60 2.5.25 End of Exposure Alarm . . . 1-60 2.5.26 Panel LED's . . . 1-60 2.5.27 HVPS Control . . . 1-60 2.5.28 ADC . . . 1-61 2.5.29 mA Low Range . . . 1-61 2.5.30 Detector Interface . . . 1-61 2.5.31 Communications Ports. . . 1-62 2.5.32 Debug RS-232 Port . . . 1-62 2.5.33 Diagnostic LED's . . . 1-62 2.6 Power Distribution (PRODIGY II Systems DF+1200 and greater) . . 1-64 2.7 Tube Head and X-ray Insert . . . 1-65 2.7.1 X-ray generation and Spectrum. . . 1-65 2.8 X-ray Generator (High Voltage Power Supply(ies)) . . . 1-66 2.9 MAX Board (PRODIGY I systems DF+11999 and lower only) . . . 1-67 2.9.1 MAX Board Function . . . 1-67 2.9.2 Dedicated +28VDC power supply . . . 1-67 2.10 XORB Board (PRODIGY I Systems DF+11999 and lower only). . . 1-68 2.11 Detector Sub System . . . 1-69 2.11.1 Detector Overview . . . 1-69 2.11.2 Detector Operation. . . 1-69 2.11.3 Detector Daughter Board Overview . . . 1-70 2.11.4 Detector Daughter Board Operation . . . 1-71 2.11.5 Detector Mother Board Overview. . . 1-72 2.11.6 Detector Mother Board Operation . . . 1-72 2.12 FOINK (PRODIGY I Systems DF+11999 and lower only) . . . 1-74 2.12.1 FOINK Functions . . . 1-74 2.12.2 Motion Control and Detection . . . 1-74 2.13 Display Panel . . . 1-75

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2.15 X-Ray Collimator Subsystem . . . 1-78 2.16 PRODIGY Specifications . . . 1-79 2.16.1 Component specifications . . . 1-79 2.16.2 Functional specifications . . . 1-79 2.16.3 Maximum scan area (long x transverse) . . . 1-79 2.16.4 Programs. . . 1-80 2.16.5 Environmental specifications. . . 1-80 2.16.6 Storage and transport environment. . . 1-81 2.16.7 X-ray generator (system no. DF+12000 and higher). . . . 1-81 2.16.8 X-ray generator (system no. DF+11999 and lower) . . . . 1-83 2.16.9 GE-LUNAR 8022 x-ray tube . . . 1-85 2.16.10 GE-LUNAR 8743 x-ray tube head assembly (system no. DF+12000 and higher) . . . 1-86 2.16.11 LUNAR 6838 x-ray tube head assembly (system no. DF+11999 and lower) . . . 1-87 2.16.12 Laser specifications. . . 1-88 2.16.13 Compatible components . . . 1-89 2.16.14 FDA Certified Components (USA Only) . . . 1-89 2.17 Secondary Calibration / Daily QA . . . 1-91 2.17.1 Secondary Calibration overview . . . 1-91 2.17.2 Starting the Daily QA (secondary calibration) . . . 1-91 Peak Test. . . 1-92 2.17.3 Tests Performed in the Secondary Calibration . . . 1-92 2.17.4 QA Database. . . 1-94 Figure 2-9. PRODIGY System Exploded View of External Covers and associated hardware . . . 1-33 Figure 2-10. PRODIGY I NTC thermistor on the Primary Terminal Block1-35 Figure 2-11. PRODIGY I Power Distribution Block Diagram . . . 1-38 Figure 2-12. PRODIGY I (systems DF+11999 and lower) Block Diagram1-39 Figure 2-13. PRODIGY I (Systems DF+11999 and lower) Peripheral

Configuration Block Diagrams . . . 1-40 Figure 2-14. PRODIGY II System / Power Block Diagram . . . 1-41 Figure 2-15. Detector Block Diagram . . . 1-69 Figure 2-16. Detector Daughter Board Operation . . . 1-71 Figure 2-17. PRODIGY Detector Module . . . 1-73 Figure 2-18. PRODIGY display panel. . . 1-75 Figure 2-19. Reference axis and target angles for tube head assembly 1-85 Figure 2-20. Anode heating/cooling curves . . . 1-86 Figure 2-21. Cathode emission characteristics . . . 1-88 Figure 2-22. X-ray tube assembly heating/cooling curves . . . 1-88 Figure 2-23. PRODIGY Daily QA printout with expected values . . . 1-95 Table 2-1. PRODIGY I (Systems DF+11999 and lower) Fuses . . . 1-42 Table 2-2. PRODIGY II (systems DF+12000 and greater) Fuses. . . 1-42 Table 2-3. PRODIGY Component Specifications . . . 1-79

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Table 2-4. X-ray generator technical information. . . 1-81 Table 2-5. Table 4. X-ray generator technical information. . . 1-83 Table 2-6. LUNAR 8022 X-ray tube technical information. . . 1-85 Table 2-7. LUNAR 8743 x-ray tube assembly technical information. . . . 1-86 Table 2-8. LUNAR 6838 x-ray tube assembly technical information. . . . 1-87 Table 2-9. Laser specifications.. . . 1-88 Table 2-10. FDA certified components (system no. DF+12000 and higher).1-89

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2.0 PRODIGY System

The PRODIGY includes the patient table and frame, X-ray tube, X-ray generator, detector, and arm. Its physical specifications are summarized in section 2.15.

The PRODIGY has a mechanical design with two separate motion systems that are capable of simultaneous operation. These are transverse, and longitudinal. Both motion systems are driven by stepper motors.

2.0.1 PRODIGY Electronics

The internal components of the scanner are safely secured by a number of panels, including the scanner's tabletop.

Figure 2-9. PRODIGY System Exploded View of External Covers and associated hardware

• The front and side panels are secured by screws from the inside. • The rear panel is secured by screws from the outside.

• The table top is screwed down from the top.

Note: Primary Service access to the electronics of the scanner is

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• The Detector electronics (in the scan arm) are secured by an upper and lower shroud, held in place by screws.

• Each metal panel is grounded to the electronics pan.

It is not usually necessary to remove the front and back panels for most service needs. However, if access is needed to the Front and Rear Longitudinal Carriages, these can be removed.

The back panel is secured by hex socket head-head screws and must be slid out of the way, for it is between the Arm Column and the frame.

If access is needed to the detector, Transverse Limit Switches or the other components mounted above in the arm, the covers of the arm must be removed.

• The upper scan arm shroud can be removed by loosening the two screws holding it in place (on the back of the arm column) and tipping it forward.

• The lower cover is held in place by four screws, two in the front and two in the back, be sure to remove the ground wire for the metal portion of the lower cover as well

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2.1 Electronics

2.1.1 Cautions

PRODIGY electronics are static sensitive, take static control precautions before servicing scanner circuitry.

PRODIGY I electronics use Negative Temperature Coefficient (NTC)

thermistors to limit the in rush current of the AC isolation transformer and the Detector Mother Board. These devices have a high resistance when cold and decrease in resistance when warm.

Figure 2-10. PRODIGY I NTC thermistor on the Primary Terminal Block

• A cool down period of 30 seconds is required before power is turned on on the system.

PRODIGY I ONLY: Failure to allow the system to “cool down” may cause the circuit breaker for the AC line to trip and / or the + 12VDC for the Detector Mother Board (DMB) will not come up to +12 VDC.

Note: The error log entry "DMB Power Cycle observed" is an

indicator that the DC power to the Detector Mother Board has been interrupted and the system should be powered down for 30 seconds to restore power to the Detector Mother Board.

PRODIGY I ONLY: The NTC’s can get hot - they are located on the AC terminal block and on the DC terminal block be careful when servicing these areas of the scanner.

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The electronic components of the PRODIGY are mounted on the grounded Electronics Pan which is horizontally fastened inside the frame.

Note: Appendix 2 A contains a layout drawing of the Electronics Pan

for PRODIGY I and PRODIGY II systems.

PRODIGY I Systems (System numbers DF+11999 and lower):

• There are four low-voltage linear DC power supplies (under 30VDC), and two high-voltage DC power supplies (to supply 76kV to the x-ray tube) on the pan.

• In addition to the power supplies, the electronics mounting chassis holds four printed circuit boards, a stepper motor controller, the audible alarm, an AC entrance/line filter/fuse holder, an isolation transformer and a terminal strip for AC power distribution to the Host PC and peripherals.

PRODIGY II Systems (System numbers DF+12000 and greater):

• There is one low-voltage DC switching power supply (under 30VDC), and one high-voltage DC power supply (x-ray generator - supplies 76kV to the x-ray tube) on the pan.

• In addition to the power supplies, the electronics mounting chassis holds one printed circuit board, a stepper motor controller, and an AC entrance/ line filter/fuse holder.

2.1.3 Scan Arm

• The scan arm contains one high-voltage power supply (1000VDC / +12 VDC input) is located in the upper arm near the X-ray detector and provides power to the Detector Array.

• The scan arm also houses the detector and 5 associated printed circuit boards, and a stepper motor contoller.

2.1.4 Power specifications

Leakage current

• Total System with Isolation Transformer: <100 microamperes. • Scanner Table alone: <100 microamperes.

Scanner input power

• PRODIGY I ONLY: The scanner has 12 different nominal inputs: 100, 110, 115, 120, 125, 127, 200, 220, 230, 240, 250, and 254 VAC. During installation, the scanner is configured for the nominal input which best matches the voltage on site.

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• PRODIGY II ONLY: The scanner can accept any AC input between 100 and 254 VAC.

• Voltage may fluctuate ±10% from the nominal value without a loss of scanner performance.

• The nominal input (range of inputs) can be found on the system label. • The rated power input is 1500 VA.

• The input power must meet IEEE 519-1992 for power quality and total harmonic distortion (THD <5%).

Scanner output power (PRODIGY I system numbers DF+11999 and lower only)

• The scanner has 3 different nominal outputs: 100, 120, 240 VAC. • The nominal voltage output of the scanner is shown on the system label. • The computer and all peripherals which use the scanner output power

must be rated for this voltage.

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2.2 PRODIGY Block Diagrams

The block diagrams for the PRODIGY system follow:

2.2.1 PRODIGY I (System numbers DF+11999 and lower) Power

Distribution Block Diagram (AC entrance)

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2.2.2 PRODIGY System Block Diagram PRODIGY I System Block

Diagram

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2.2.3 PRODIGY I Peripheral Configuration Block Diagrams

Figure 2-13. PRODIGY I (Systems DF+11999 and lower) Peripheral Configuration Block Diagrams

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2.2.4 PRODIGY II System / Power Block Diagram

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2.3 PRODIGY Fusing

All fuses are 250V, low breaking capacity (25A minimum)

Table 2-1. PRODIGY I (Systems DF+11999 and lower) Fuses

PRODIGY II (systems DF+12000 and greater) Fuses

All fuses are 250V, low breaking capacity (25A minimum) PRODIGY I (system numbers DF+11999 and lower) Fuses

Fuse Rating Type*

F1 (Computer AC) T 2.0 AL 5x20MM F2 (Computer AC) T 2.0 AL 5x20MM F3 (+5, +/-12 VDC PS (1)) T 1.25 AL 5x20MM F4 (+5, +/-12 VDC PS (2)) T 1.25 AL 5x20MM F5 (+26VDC PS) T 2.5 AL 5x20MM F6 (+28VDC PS) T 0.63 AL 5x20MM F7 (+5, +/-12VDC PS (1)) T 1.25 AL 5x20MM F8 (+5, +/-12VDC PS (2)) T 1.25 AL 5x20MM F9 (+26 VDC PS) T 2.5 AL 5x20MM F10 (+28 VDC PS) T 0.63 AL 5x20MM MAX PCB F1 F 0.5 AL 1/4x1 1/4 in.

Fuse

Rating

Type

Condor PS F1 F3.15 AH 5x20 mm Condor PS F2 F3.15 AH 5x20 mm COndor PS F3 F3.15 AH 5x20 mm

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2.4 PRODIGY I (system numbers DF+11999 and

lower) Single Board Controller

2.4.1 SBC Functions

The microprocessor-based Single Board Controller (SBC) provides overall operation and control of the scan table.

Control Functions

• Control of x-ray source power supplies, and shutter / collimator in a fail safe manner.

• Provides control signals for two external stepper motor drives (Centent) to scan patient in a fail safe manner and senses limit switch actuation at the limits of travel (via FOINK see 2.11).

• Controls the detector array (communicates with the Detector Mother Board, section 2.10.2).

• Responds to external scanner failure signals (interrupts generated by SBC, FOINK see 2.11, and Detector Mother Board see 2.10).

Communication

• Communicates with PC host via an optically isolated RS-422 interface. • Collects data from the detector array.

2.4.2 SBC Reset

All SBC circuitry resets when the microprocessor resets. This is done during power up, and can also be done over the communication port (via the host), through connections to other circuit boards (especially the Detector Mother Board, as a fail-safe shutdown), the by pressing the reset button on the SBC, by pressing the Emergency Stop Button on the arm, or when a fault is

detected by the SBC or the FOINK (section 2.11.1). Error Conditions Sensed by the SBC:

• Loss of Communications with the Detector Mother Board (DMB). • Loss of Communications with the Host PC.

• Limit Switch tripped when shutter is open.

• Limit Switch depressed when commands are being sent. • Failure in x-ray source kV programming

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• Interrupt sent by FOINK

The DMB will reset the SBC if it detects an error. Error Conditions of the DMB sensed by the SBC:

• PLD programming failure • Loss of +5 or +12 VDC

• Loss of Communications with SBC • Corrupt FIRMWARE

• FLASH RAM Failure

• DTR Reset button on the DMB is pressed

2.4.3 SBC / Host PC Interface

The SBC communicates with the Host PC via an RS-422 interface. This is a serial connection capable of transmitting more data than a standard RS-232 port. As it is not a standard serial port a RS-485 card must be installed into one of the Host PCs expansion slots and the port must be configured correctly for the PRODIGY to operate correctly (see DXPC2000 chapter 5 appendices).

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2.5 PRODIGY II Combined Single Board Controller

(cSBC) (systems DF+12000 and greater)

The cSBC printed wiring board (PWB) is an eight layer rectangular board measuring 7.400" x 8.100". The PWB is mounted in the via four mounting holes located 1/4" from each corner and 2 additional interior mounting holes. The components are primarily surface mount, with board connectors, headers and a few single-style ICs being the only exceptions.

Four layers were dedicated for routing layers. Sensitive signals were noted and routed manually and isolated from more powerful signals to reduce signal interference and crosstalk on the same routing layer. The main power and ground planes were stacked adjacently on the central inner layers to increase inter-planar capacitance thus reducing ground bounce and power supply noise. Traces on the top and bottom layers were kept as short as reasonably possible and tapped down to an internal trace layer through vias.

Component placement is arranged to separate analog from digital circuitry. Further isolation was achieved by segmenting the power and ground planes into analog and digital sections and denying analog/digital plane overlap, thus preventing digital noise from coupling into the analog section. All scanner control I/O is run via connectors located on the +24V plane section. The +24V plane is fully optically isolated from both the analog and digital plane areas to prevent motor noise from coupling into the analog section, to prevent DC switching noise from radiating on scanner cables, and to prevent ESD presented at cable inputs from reaching the digital IC's.

2.5.1 cSBC System Architecture

The cSBC employs an Intel 80C251 micro-controller as its processor. This processor provides 1K of on-board RAM and no on-board ROM. The controller is clocked at 16 MHz using a crystal.

cSBC Memory Space

The cSBC is designed to support a JEDEC-standard, non-volatile FLASH memory device up to 512K x 8 bits in size for code and fixed data. The board supports either 128K or 512K SRAM memory device as needed for program volatile memory. Complete address decoding is provided via the MAX PLD, the CBSC bus master, allowing the address space to be arbitrary and changed via the PLD code. The 80251 can address four 64K segments, referred to as 0x00, 0x01, 0xFE and 0xFF as per Intel literature. The firmware has the ability to map any FLASH or SRAM segment to any CPU segment via SFR’s in the MAX PLD.

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At startup the CPU executes the boots code which programs the FLEX PLD and then maps in either NT or Prodigy runtime firmware as appropriate based on the most significant bit of the CCA REV register. To switch from boot code to run code the firmware jumps to SRAM and executes a code snippet which pages the boot code out of 0xFF and the desired firmware into 0xFF. The snippet then jumps from SRAM back to 0xFF to execute the firmware. A boot jumper, JP4 is provided to optionally force the CPU to remain in the boot code. When the boot jumper is installed the boot code runs the host port at 115.2KB.

SRAM

The cSBC contains a single 128K x 8 bit SRAM which provides read/write memory. The SRAM's segments are arbitrarily mapped to any CPU segment by the CPU mapping registers.

2.5.2 cSBC Functions

The microprocessor-based Single Board Controller (cSBC) provides overall operation and control of the scan table.

FLEX PLD Peripherals

The majority of scanner related programmable logic functionality is contained in the FLEX PLD, an Altera EPF6024AQC208-3 device. Device programming is handled exclusively by the CPU. On each cold boot the CPU reprograms the FLEX devices from an image stored in it's FLASH. As such a firmware download of a new FLEX image is required to permanently upgrade the PLD code.

The functional components of the programmable logic are discussed in the following subsections. Polarity of operation can be inferred from bit names and use of preceding slash for inverted logic bits.

Note that ports A-F are reloaded with default values at time of CPU reset and remain in the default state until SCANNER_RESET has been cleared and new values are written by the firmware. Defaults for port F and all other registers are invoked at power up only.

PORT A

Bit Name R/

W

Def. Description

0 trans_enable R/W 0 Transverse motor enable – low blocks trans motor pulses and

forces Centent drive to standby current level.

1 /trans_fwd R/W 0 Transverse motor direction control.

2 /shutter_open_ctrl R/W 1 Shutter solenoid control.

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4 long_enable R/W 0 Longitudinal motor enable – low blocks trans motor pulses and forces Centent drive to standby current level.

5 /long_fwd R/W 0 Longitudinal motor direction control.

6 long_lsw_override R/W 0 Longitudinal limit switch override – prevent limit switch contact from blocking step pulses at hardware level

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PORT B

PORT C

Bit Name R/

W

0 /trans_front_lsw R N/A Transverse front limit switch position.

1 /trans_back_lsw R N/A Transverse back limit switch position.

2 /long_foot_lsw R N/A Longitudinal foot limit switch position.

3 /long_head_lsw R N/A Longitudinal head limit switch position.

4 trans_count_eq[0] R N/A Set when transverse step counter equals zero.

5 long_count_eq[0] R N/A Set when longitudinal step counter equals zero.

6 /shutter_open_sense R N/A Shutter limit switch position.

7 /collimator_open_sense R N/A Collimator limit switch position.

Bit Name R/

W

0 /long_rev_pos R N/A Patient positioner (joystick) input.

1 /long_fwd_pos R N/A Patient positioner (joystick) input.

2 /trans_rev_pos R N/A Patient positioner (joystick) input.

3 /trans_fwd_pos R N/A Patient positioner (joystick) input.

4 /hvps_ac_relay R/W 1 Enable AC power to X-ray HVPS.

5 /motor_fail_enable R/W 1 Arm logic to shutdown scanner if OMI inputs not sensed.

6 ags_enable R/W 0 Enable detector automatic gain control feedback circuit.

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PORT D

PORT E

Bit Name R/

W

0 flex_max_i/o_[0] R/W 0 Output signal to MAX PLD (diagnostic use only).

4 flex_diag_3 R/W 0 Firmware controlled diagnostic LED.

5 pit_enable R/W 0 Enable Programmable Interval Timer output pulses.

7 /laser_on R/W 1 Patient locator laser control.

Bit Name R/

W

0 low_range_dac R/W 0 Switches mA DAC from 2.048V to 0.500V reference.

1 trans_motor_accel R/W 0 Enables motor interrupt on every micro step.

2 low_range_adc R/W 0 Switches ADC from 5.000V to 0.500V reference.

3 long_motor_accel R/W 0 Enables motor interrupt on every micro step.

4 hvps_vendor_id R N/A For 7681 supply, 0 = Spellman, 1 = Bertan.

5 iq_hvps R N/A Set by resistor placement to indicate 0311/0312 supplies.

6 /hvps_enable_status R N/A Enable status monitor from 7681 supply.

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PORT F

PORT G

2.5.3 TRANS / LONG MOTOR Control and Status

Dual axis stepper motor control is provided entirely by the FLEX PLD. To make a typical move the firmware loads a starting velocity into the 16 bit VELOCITY register, the total number of steps for the move into the 16 bit TARGET register, and step at which to next interrupt the CPU into the 16 bit STEP register. Velocity is in terms of periods of the 2.0MHz fundamental clock per micro step pulse to the stepper drive. The drives provide 10 micro steps per full step. The firmware can track move status by reading the 16 bit READ register.

Bit Name R/

W

0 /motion_fail_enable R/W 1 Arm scanner shutdown if OMI pulses w/o step pulses.

1 long_motor_fail_axis R/W 0 Motor fail circuitry axis control, clear for transverse.

2 /hvps_enable R/W 1 Enable output to 7681 supply.

4 /arm_estop_sense R N/A Emergency stop sense bit.

5 spare_jmp_[1] R N/A Unused input, resistor or jumper selectable on CCA.

6 spare_jmp_[0] R N/A Unused input, resistor or jumper selectable on CCA.

7 cpu_p1_2 R N/A Firmware controlled diagnostic LED.

Bit Name R/

W

0 adc_mux_[0] R/W 0 ADC analog MUX input selection control bit.

4 adc_mux_enable R/W 0 ADC MUX output enable control.

5 8ms_clock R/W 0 Clock output provided to MAX PLD.

6 unused N/A N/A For expansion.

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As part of the setup for a move the host and/or firmware must enable the motors via the /motor_power, trans_enable, and long_enable outputs and setup the trans_lsw_override, long_lsw_override, /motion_fail_enable, / motor_fail_enable, and long_motor_fail_axis outputs as desired. If the system is in scanner reset for any reason the FLEX PLD will over-ride the /

motor_power output and prevent 24V power from reaching the motor drives. Addressing for the motor control interface is provided below.

2.5.4 AGS ROLL

This is a read only 8 bit register which returns the count of AGS roll-over events since the previous read of the register. The AGS roll counter is reset on read only - it is not tied to the PIT's sample clock.

2.5.5 AGS DAC

This port provides R/W access to the AGS circuit's 8 bit U/D counter. The counter is tied via a dedicated 8 bit bus to the AGS DAC. The DAC's analog voltage is tied to the gain control input of the variable gain amplifier (VGA) used to control gain of the detector input signal. As such the firmware can read this counter to determine the current DAC voltage level and hence gain level. If ags_enable is low this port gives the firmware direct control of the AGS DAC as a parallel R/W device. If ags_enable is high, the firmware can write to the port but the DAC will continue to respond to UP/DOWN requests from the AGS DCA circuitry and hence quickly return to the AGS current operating voltage.

HE/LE COUNTERS

These read only ports provide access to the 16 bit event counters which are incremented each time the DCA circuitry detects an input pulse within the HE or LE windows (as defined by the LEL, LEH, HEL, and HEH DAC settings). These counters are read in two 8 bit bus cycles, MSB then LSB. The event counters themselves consist of a counting element and a bus element. On the rising edge on the PIT output pulse the counting elements are latched to the bus element. The PIT output is also tied to CPU external INT 1 and as such the firmware interrupt handler then has until the next rising PIT edge to read the counters before the bus elements are latched over with the next sample count and data is lost.

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The PLD provides a programmable interval timer (PIT) to the CPU. The PLD prescales it's input clock to generate a PIT base clock of 100KHz. The CPU writes a 2 byte word to the PIT reload register MSB/LSB. The CPU then raises the pit_enable bit to start the timer. In response to the rising edge on the pit_enable, the PIT loads the reload word into it's counting element and begins counting down. When the count rolls under the PIT asserts /

SAMPLE_INT, reloads the counting element, and begins another count down sequence. The /SAMPLE_INT line is tied internally to the HE and LE event counters and causes a synchronous latch of both counting elements. The / SAMPLE_INT line is also tied to the processor's 2nd external interrupt line, / INT1. The CPU interrupt handler reads the latched event counters and ships the data to the host.

2.5.6 SCANNER RESET

The scanner reset register is used to provide failsafe shutdown operation of the scanner. A falling edge on any of the inputs to this register will latch the current value of the register and drop the /SCAN_FAIL_ANY output. The MAX PLD latches the master reset register and raises CPU_RESET in response to the falling edge on /SCAN_FAIL_ANY. The MAX PLD also provides

SCANNER_RESET as the logical OR of CPU_RESET and!/

SCAN_FAIL_ANY. The FLEX PLD uses it's SCANNER_RESET input as the enable bit to the tri-state buffers used to drive all safety critical output lines including shutter control, HVPS relay control, motor relay control, etc. As such the scanner is locked into a fail-safe mode whenever SCANNER_RESET is asserted.

The MAX's master reset register will remain latched until the next rising edge on the HOST_RTS input. When the cSBC is latched into reset by a scanner error it will remain in CPU reset until the host drops the RTS line and re-asserts it. It will remain in scanner reset until the CPU reads the scanner reset register following the next raising edge of the RTS line at which the condition causing the /SCAN_FAIL_ANY has been cleared. The firmware passes the value of the reset registers to the host to allowing the host to display appropriate error messages to the operator. The host will be unable to perform any scanner related operations until the SCANNER_RESET has been cleared. Red diagnostic LED's (see 2.5.33) are provided for both scanner and CPU reset lines. The CPU reset line is tied to the host CTS output such that the host sees a CTS event when the cSBC enters CPU reset. The host code provides a CTS event handler which reads the reset registers and prompts the user accordingly.

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The firmware can also initiate a reset sequence in response to fatal error conditions by writing a 'death code' to the suicide reset register. Resets can also be initiated by the manual push button on the cSBC and by a low 5VDC power condition as sensed by the MAX705 supervisor. The scanner register is also latched at the end of read cycles such that current status can be

ascertained by a double read. A bit map of the scanner reset register is provided below

2.5.7 GE-LUNAR Model 7861 X-ray Generator Errors

The HVPS error register is used to monitor the status of the 7681 X-ray source HVPS. If the register value is not equal to 0xF when /hvps_enable is low, the FLEX will raise the HVPS_ERROR_INT output to the MAX PLD. The MAX PLD latches this into the IIR register and issues an interrupt to the CPU. As such status of the HVPS is monitored when the unit is enabled. The handler for HVPS interrupt reads this register to determine the cause of the interrupt. The HVPS register is also latched at the end of read cycles such that current status can be ascertained by a double read. A bit map of the register is provided below.

Bit Name R/

W

0 /

thermostat_open_sense

R N/A Tube head thermostat over temperature.

1 /external_estop_sense R N/A Emergency stop input from external options block.

2 /dc_power_fail R N/A Loss of one or more of +5VDC,+12VDC,-12VDC, or +24VDC.

3 /long_motor_fail R N/A Motor failure detected on longitudinal axis.

4 /trans_motor_fail R N/A Motor failure detected on transverse axis.

5 /dmb_error R N/A DMB dropped it’s CTS indicating a DMB reset event.

6 /motion_fail R N/A OMI pulses detected without step pulse (manual arm motion).

7 /watchdog_reset R N/A Watchdog time-out indicates firmware crash.

Bit Name R/

W

0 /hvps_error_0 R N/A Error code bit from 7681 supply.

3 hvps_enable_status R N/A Set when /hvps_enable == /hvps_eanble_status

4 Unused N/A N/A Expansion room.

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2.5.8 DC FAIL

The DC fail error register latches the status of the DC power monitors at the time of reset. If scanner reset code indicates /dc_power_fail the firmware can read this register to identify the specific DC source failure. The register is also latched at the end of read cycles such that current status can be ascertained by a double read.

2.5.9 DCA / AGS / BIAS DAC's

The cSBC uses a single 10 bit octal DAC, the Linear Technology LTC1660, to generate the AGS and DAC window reference voltages and the bias program voltage. The DAC utilizes a serial interface and as such is not accessed with a traditional CPU write cycle. To load the device the firmware writes to the DAC address listed above, in response to which the MAX drops the /CS line to the device. The firmware then manipulates the local serial bus clock and data lines to load the DAC setting. The desired DAC channel address in encoded into the first 4 bits of the output data word. A read is then made to the DAC address, in response to which the MAX raises the /CS line. See device data sheet and analog section below for further DAC details.

Bit Name R/

W

0 /plus_scanner_fail R N/A Loss of +24V power input.

1 /plus_analog_fail R N/A Loss of +12V power input.

2 /minus_analog_fail R N/A Loss of -12V power input.

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2.5.10 KV/mA DAC

The cSBC uses a single 12 bit dual DAC, the Linear Technology LTC1454, to generate the HVPS kV and mA program voltages. The DAC utilizes a serial interface and as such is not accessed with a traditional CPU write cycle. To load the device the firmware writes to the DAC address listed above, in response to which the MAX drops the /CS line to the device. The firmware then manipulates the local serial bus clock and data lines to load the DAC setting. Both DAC channels must be written together, CHA (kV) first followed by CHB (mA) in a 24 bit stream packet. A read is then made to the DAC address, in response to which the MAX raises the /CS line. See device data sheet and analog section below for further DAC details.

2.5.11 ARC/FIL DAC

The cSBC uses a single 10 bit dual DAC, the Linear Technology LTC1661, to generate the HVPS filament limit and arc detect threshold voltages. The DAC utilizes a serial interface and as such is not accessed with a traditional CPU write cycle. To load the device the firmware writes to the DAC address listed above, in response to which the MAX drops the /CS line to the device. The firmware then manipulates the local serial bus clock and data lines to load the DAC setting. The desired DAC channel address in encoded into the first 4 bits of the output data word. A read is then made to the DAC address, in response to which the MAX raises the /CS line. See device data sheet and analog section below for further DAC details.

2.5.12 PEAK DAC

The cSBC uses a 12 bit DAC, the Linear Technology LTC8043, to generate the detector peak gain voltage. The DAC utilizes a serial interface and as such is not accessed with a traditional CPU write cycle. To load the device the firmware manipulates the local serial bus clock and data lines to output load the DAC setting and then performs a write/read cycle to the DAC address listed above to pulse the DAC's load line low. See device data sheet and analog section below for further DAC details.

2.5.13 MAX PLD Peripherals

The programmable logic section is based on an Altera MAX

EPM7128STC100-15 device. The configuration pins for this device are taken to a JTAG style 10 pin header to allow for in-circuit programming of the device from the Altera Byte-Blaster. The MAX device is FLASH based (non-volatile) and is programmed at the time of CCA assembly. The functional components of the programmable logic are discussed in the following subsections.

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2.5.14 Interrupts

The CPU's interrupt capacity is effectively increased by running several interrupt signals to a register in the MAX PLD and tying the register output to the CPU external INT 0 input. The firmware interrupt handler for INT 0 then reads this register to identify the source of the interrupt and handles it

accordingly. The firmware then writes a bit masked '1' back to the IIR to clear the bit of the interrupt it has serviced (the R/C in the table stands for READ/ CLEAR).

2.5.15 MASTER RESET

The master reset register will force a CPU and scanner reset condition on the falling edge of any of its listed inputs. The contents of the register will be latched at the time of reset such that when the CPU next comes out of reset the firmware can read the register to determine what caused the preceding reset and report the appropriate code to the host. If the reset was cause by the CPU_RST_WR input, the suicide reset register contains the specific error code. If the reset was cause by the /SCAN_FAIL_ANY input, the scanner reset register contains the specific error code.

The CPU and scanner resets will remain latched until the next rising edge of the RTS input. At this time the CPU reset will be cleared if /POWER_RESET bit is not asserted and the scanner reset will be cleared if /SCAN_FAIL_ANY is high.

Bit Name R/

W

0 HOST_UART_INT R/C N/A Host UART interrupt.

1 DEBUG_UART_INT R/C N/A Debug UART interrupt.

2 DMB_UART_INT R/C N/A DMB UART interrupt.

3 HVPS_ERROR_INT R/C N/A HVPS error interrupt.

4 8mS_CLOCK R/C N/A 8ms clock tick interrupt from FLEX PLD.

5 POWER_FAIL_INT R/C N/A Power down pending in 5ms interrupt from DC supply.

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2.5.16 SUICIDE RESET

The CPU Reset SFR is a byte register into which the CPU can write a failure code. In response to the write the MAX PLD will store the failure code and assert the CPU_RESET line. The CPU_RESET line will be released on the next rising edge of the host RTS, at which time the CPU will be able to read the bit code from this SFR to determine the cause of the previous reset.

2.5.17 MISC OUT

The misc. output register is used to control the misc. output functions listed in the following table.

Bit Name R/

W

0 /POWER_RESET R N/A MAX705 supervisor detects VCC < 4.65V.

1 /HOST_RTS R N/A RTS reset request from host via comm line.

2 /MANUAL_RESET R N/A Push button pressed.

3 Unused R N/A Expansion room, reads as ‘1’.

6 CPU_RST_WR R N/A Write to the suicide register, read suicide reg for error code.

7 /SCAN_FAIL_ANY R N/A Scanner reset register latched, read scanner reg for error code.

Bit Name R/

W

1 MAX DIAG_2 R/W 0 Firmware controlled diagnostic LED.

2 DMB HWPT R/W 0 Enable direct connect of host and DMB XCVR’s, bypassing

UART’s, for maximized scan data bandwidth DMB to host.

3 RESET OVERRIDE R/W 1 Enable override of CPU_RESET signal. Set to 1 on power-up such

that firmware can load the FLEX PLD at power-up regardless of the host RTS state.

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2.5.18 MISC IN

The misc. output register is used to control the misc input functions listed in the following table

2.5.19 Stepper Motor Control

The stepper motors use the same interface design as used on IQ and Prodigy. The FET exhibits a lower voltage drop and hence provides more available power at the drives for a given source voltage - essentially recovering the voltage lost in dropping the DC supply from the 26V used on IQ/Prodigy to the 24V which is readily available in commercial switchers. Diodes are placed in series on the Centent power lines to prevent back EMF generated when the arm is moved manually from reaching the 24V planes and damaging the cSBC. A dual FET circuit is used to minimize the voltage drop on the 24V plane due to in-rush current when the motors are enabled. A circuit in the FLEX implements a 2 stage turn on when the firmware lowers /motor_enable. Q15 is enabled first to provide 24V to the Centents through R381 and R384, thus limiting the in-rush current. After the current pulse has stabilized Q14 is enabled to bypass the inrush limiting resistors. Q15 is then disabled and the motors are at full power. An PTC is provided on the source of Q15 such that the current limiting resistors will not be smoked if Q15 is inadvertently left enabled.

Bit Name R/

W

0 BOOT JUMPER R N/A JP4, placed to force firmware to remain in boot code.

1 CPU_P1_2 R N/A Input from CPU port 1, pin 2 (diagnostic use only).

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2.5.20 OMI Input

The optical motion interrupt (OMI) sub-system connects to the transverse and longitudinal OMI CCA's. The OMI CCA's are located on the far end (the gear end farthest from the motor) of each drive axis. When the axis is in motion a small toothed wheel spins through the OMI opto's beam and pulses are sensed back on the cSBC. In this manner the system can sense a drive circuit, motor, or belt failure which might otherwise result is a concentrated exposure point during a patient scan. The OMI inputs are similar to those used on the DPX-IQ. 74LS14's are added for hysteresis which provides a clean direct interface to the PLD. As on Prodigy, logic in the FLEX PLD is used to qualify the CH A and CH B inputs into a single 'valid motion' output. Based on the phases of the square wave inputs on CH's A&B, the FLEX is able to sense a change in direction. The circuit provides hysteresis to reject false motion inputs resulting from scanner vibration when a wheel edge stops in the center of the opto beam at the end of a move.

2.5.21 Patient Positioners

Four optically isolated inputs are provided for patient positioning. These are used by the firmware to implement a joystick mode which is used in

conjunction with the laser to position the X-ray beam as desired over the patient immediately prior to a scan. 74LS14 inverters are used to provide hysteresis and isolate the FLEX PLD inputs from the slow rise times of the opto output signals.

2.5.22 Limit Switches

Four optically isolated inputs are provided for limit switches. These are used by the firmware to define the transverse and longitudinal table limits. 74LS14 inverters are used to provide hysteresis and isolate the FLEX PLD inputs from the slow rise times of the opto output signals.

2.5.23 X-ray Source Control / Mechanical Interlocks

The cSBC is designed such that a high on the scanner reset net disables all scanner functionality and assures a know, fail safe, state. All scanner control outputs are driven by the FLEX PLD. The FLEX outputs drive the low side of a PS2501 opto coupler emitter. The far side of all these opto circuits are configured such that the opto has to be energized for the scanner function to be active. As such the FLEX has to sink current to energize the opto and activate the desired scanner function. Internally the FLEX code defines these outputs as tri-state buffers, each of which has their enable line tied to the scanner reset net. As such a scanner reset will force all these FLEX scanner outputs to a high impedance state, de-energizing the opto's and disabling the scanner.

The FLEX device is SRAM based and hence must be reprogrammed by the CPU at power up. When the device is not programmed all I/O pins default to the high impedance state. As such the scanner will also be in a fail safe state when the FLEX is not programmed. The CPU port 1, pin 2 also runs directly to the FLEX's ENABLE pin.

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The cSBC provide a failsafe mechanism independent of the programmable logic via the +5V_IO circuit. If one or more of either the stop, external E-stop, or tube thermostat is open, the FET driving the +5V_IO net from the +5VDC plane will be disabled. The +5V_IO net provides power to the emitter anode of all opto's which drive critical scanner functions. As such the scanner will enter a failsafe state in response to these mechanical interlocks, even in the event of a PLD device failure. The +5V_IO FET will also be disabled by either a HOST_RTS or CPU_RESET.

2.5.24 Shutter / Collimator Drive

The shutter and collimator solenoid drive circuits are the same as that used on Prodigy I. The FLEX drives an isolation opto which in turn switches a pair of FET's to control solenoid current. The first FET is used for an initial 'hard hit' on open commands. It presents 24V directly to the solenoid for several hundred msec's, resulting in a large initial current pulse to the solenoid. The second FET provides the 'hold' current through a pair of current limiting power resistors. The hold FET is tied directly to the /shutter_open_ctrl bit. Note that the collimator drive is populated only for NT-A and IQ upgrades which use the old style IQ collimator assembly. The nominal values of the power resistors is changed between the NT and Prodigy II BOM's to support both the traditional linear solenoid of IQ, and the rotary solenoid of Prodigy. A jumper or DNP'd resistor is used to drive the IQ_SHUTTER line to the FLEX such that both mechanical and optical shutter limit switches are supported.

2.5.25 End of Exposure Alarm

An on-board end of exposure alarm is provided. The alarm chosen is the board mount equivalent of that used on Prodigy I.

2.5.26 Panel LED's

The 4 panel LED's, power on, X-ray on, source exposed, and laser on, are all driven PS2501-2 opto's through 750R0 / 1W current limiting resistors.

2.5.27 HVPS Control

The HVPS analog control interface is designed to provide maximum

performance at minimum cost. A single, 16 channel multiplexed, 16 bit, high accuracy, ADC is used in conjunction with several lower cost, lower bit resolution DAC's. Absolute accuracy of DAC's is poor but errors are calibrated out by the firmware which monitors the actual DAC output via the ADC. In this scenario DAC integral non-linearity (INL) specs are not important, sufficient differential non-linearity (DNL) is all that is required. Serial DAC's and ADC's are chosen to conserve board space and simplify routing. Serial parts are typically also lower cost as their maximum bandwidth is limited by the serial baud rate.

The HVPS AC is enabled via a relay controlled by the cSBC. The line is primarially used to disable the HVPS by removing the AC to the HVPS via the relay. AC Power to the HVPS can be left on for up to one hour after

(55)

A jumper and/or DNP'd resistor pad is provide to drive the IQ_HVPS line, which the firmware reads to determine which HVPS it is intended to operate. The PWB provides lemo style connector pads for use with the traditional 0311/ 0312 HVPS and MAX CCA. For the 7681 HVPS the lemos are DNP'd and a single DB-25 connector is used to control the HVPS. Tranzorb pads are provide on the PWB and are expected to be populated only if deemed necessary by EMC testing. An opto bank is also provided to support the digital interface to the 7681. See Lunar dwg 7681-SPC for details.

2.5.28 ADC

The Burr Brown ADS8320 16 bit, serial, single channel ADC was chosen for the cSBC for its high resolution, and excellent accuracy.

An Analog devices AD586 +5V voltage reference is used. The part was selected for it low noise and high accuracy

Overall the ADC and reference give the cSBC +/-5mV analog accuracy 11.2 DAC's

A single LTC1454 12 bit, serial, dual channel, DAC is used to provide the kV and mA program voltages. The part was chosen for it low cost, ready

availability at national distributors, and excellent DNL specifications. The DAC is used in the x2 configuration such that the full scale output is twice the reference voltage. Voltage outputs feed back to the ADC MUX such that firmware can calibrate out DAC INL errors.

A single LTC1661 10 bit, serial, dual channel, DAC is used to provide the arc threshold and filament current limit input voltages to the new 7681 HVPS. The part was chosen for it low cost, ready availability at national distributors, and reasonable DNL specifications. Voltage outputs are not fed back to the ADC MUX as high accuracy is not required on these threshold inputs.

2.5.29 mA Low Range

To support future scan modes, an mA low range circuit is provided. The FLEX PLD provides a control bit by which the firmware can switch the mA DAC reference voltage from 2.048V to 0.5V, hence decreasing the LSB size, hence allowing the firmware to take smaller voltage steps when ramping to low uA settings. A second control bit is provided to switch the ADC from 5.0 to 0.5V reference.

2.5.30 Detector Interface

The cSBC provides a RS-422 communications post to the Detector Mother Board. The CSBC does not participate in any Detector data manipulation, all analysis and Detector control is performed at the DMB.