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Industrial ScopeMeter

123

Service Manual

4822 872 05375 August 1997, Rev. 3, 01/00
1997 Fluke Corporation. All rights reserved. Printed in the Netherlands All product names are trademarks of their respective companies.

SERVICE CENTERS To locate an authorized service center, visit us on the World Wide Web: http://www.fluke.com or call Fluke using any of the phone numbers listed below: +1-888-993-5853 in U.S.A. and Canada +31-402-678-200 in Europe +1-425-356-5500 from other countries

Table of Contents

Chapter 1

Title

Page

Safety Instructions ............................................................................. 1-1 1.1 Introduction................................................................................................. 1.2 Safety Precautions....................................................................................... 1.3 Caution and Warning Statements................................................................ 1.4 Symbols....................................................................................................... 1.5 Impaired Safety ........................................................................................... 1.6 General Safety Information......................................................................... 1-3 1-3 1-3 1-3 1-4 1-4

2

Characteristics ................................................................................... 2-1 2.1 Introduction................................................................................................. 2.2 Dual Input Oscilloscope.............................................................................. 2.2.1 Vertical ................................................................................................ 2.2.2 Horizontal ............................................................................................ 2.2.3 Trigger ................................................................................................. 2.2.4 Advanced Scope Functions.................................................................. 2.3 Dual Input Meter ......................................................................................... 2.3.1 Input A and Input B ............................................................................. 2.3.2 Input A ................................................................................................. 2.3.3 Advanced Meter Functions.................................................................. 2.4 Miscellaneous ............................................................................................. 2.5 Environmental ............................................................................................. 2.6 Service and Maintenance ............................................................................ 2.7 Safety .......................................................................................................... 2.8 EMC Immunity ........................................................................................... 2-3 2-3 2-3 2-4 2-4 2-5 2-5 2-5 2-8 2-8 2-9 2-10 2-11 2-11 2-12

3

Circuit Descriptions ........................................................................... 3-1 3.1 Introduction................................................................................................. 3.2 Block Diagram ............................................................................................ 3.2.1 Channel A, Channel B Measurement Circuits..................................... 3.2.2 Trigger Circuit ..................................................................................... 3.2.3 Digital Circuit ...................................................................................... 3.2.4 Power Circuit ....................................................................................... 3.2.5 Start-up Sequence, Operating Modes .................................................. 3-3 3-3 3-4 3-4 3-5 3-6 3-7

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3.3 Detailed Circuit Descriptions...................................................................... 3.3.1 Power Circuit ....................................................................................... 3.3.2 Channel A - Channel B Measurement Circuits ................................... 3.3.3 Trigger Circuit ..................................................................................... 3.3.4 Digital Circuit ...................................................................................... 4

3-9 3-9 3-15 3-20 3-25

Performance Verification ................................................................... 4-1 4.1 Introduction................................................................................................. 4.2 Equipment Required For Verification ........................................................ 4.3 How To Verify ............................................................................................ 4.4 Display and Backlight Test ......................................................................... 4.5 Input A and Input B Tests ........................................................................... 4.5.1 Input A and B Base Line Jump Test .................................................... 4.5.2 Input A Trigger Sensitivity Test .......................................................... 4.5.3 Input A Frequency Response Upper Transition Point Test................. 4.5.4 Input A Frequency Measurement Accuracy Test ................................ 4.5.5 Input B Frequency Measurement Accuracy Test ................................ 4.5.6 Input B Frequency Response Upper Transition Point Test ................. 4.5.7 Input B Trigger Sensitivity Test .......................................................... 4.5.8 Input A and B Trigger Level and Trigger Slope Test.......................... 4.5.9 Input A and B DC Voltage Accuracy Test .......................................... 4.5.10 Input A and B AC Voltage Accuracy Test ........................................ 4.5.11 Input A and B AC Input Coupling Test ............................................. 4.5.12 Input A and B Volts Peak Measurements Test.................................. 4.5.13 Input A and B Phase Measurements Test .......................................... 4.5.14 Input A and B High Voltage AC/DC Accuracy Test......................... 4.5.15 Resistance Measurements Test.......................................................... 4.5.16 Continuity Function Test ................................................................... 4.5.17 Diode Test Function Test .................................................................. 4.5.18 Capacitance Measurements Test ....................................................... 4.5.19 Video Trigger Test............................................................................. 4-3 4-3 4-3 4-4 4-5 4-6 4-7 4-8 4-8 4-9 4-10 4-10 4-11 4-14 4-15 4-16 4-17 4-18 4-19 4-20 4-21 4-22 4-22 4-23

5

Calibration Adjustment ...................................................................... 5-1 5.1 General ........................................................................................................ 5.1.1 Introduction.......................................................................................... 5.1.2 Calibration number and date................................................................ 5.1.3 General Instructions............................................................................. 5.2 Equipment Required For Calibration.......................................................... 5.3 Starting Calibration Adjustment ................................................................. 5.4 Contrast Calibration Adjustment ................................................................ 5.5 Warming Up & Pre-Calibration .................................................................. 5.6 Final Calibration ......................................................................................... 5.6.1 HF Gain Input A&B ............................................................................ 5.6.2 Delta T Gain, Trigger Delay Time & Pulse Adjust Input A................ 5.6.3 Pulse Adjust Input A (firmware V01.00 only) .................................... 5.6.4 Pulse Adjust Input B............................................................................ 5.6.5 Gain DMM (Gain Volt) ....................................................................... 5.6.6 Volt Zero.............................................................................................. 5.6.7 Zero Ohm (firmware V01.00 only)...................................................... 5.6.8 Gain Ohm............................................................................................. 5.6.9 Capacitance Gain Low and High......................................................... 5.6.10 Capacitance Clamp & Zero................................................................ 5.6.11 Capacitance Gain ............................................................................... 5.7 Save Calibration Data and Exit................................................................... 5-3 5-3 5-3 5-3 5-4 5-4 5-6 5-7 5-7 5-7 5-9 5-10 5-11 5-11 5-13 5-13 5-14 5-15 5-15 5-16 5-16

Contents (continued)

6

Disassembling the Test Tool ............................................................. 6-1 6.1. Introduction................................................................................................ 6.2. Disassembling Procedures ......................................................................... 6.1.1 Required Tools .................................................................................... 6.2.2 Removing the Battery Pack ................................................................. 6.2.3 Removing the Bail ............................................................................... 6.2.4 Opening the Test Tool ......................................................................... 6.2.5 Removing the Main PCA Unit............................................................. 6.2.6 Removing the Display Assembly......................................................... 6.2.7 Removing the Keypad and Keypad Foil.............................................. 6.3 Disassembling the Main PCA Unit ............................................................. 6.4 Reassembling the Main PCA Unit .............................................................. 6.5 Reassembling the Test Tool........................................................................ 6-3 6-3 6-3 6-3 6-3 6-3 6-5 6-6 6-6 6-6 6-8 6-8

7

Corrective Maintenance ..................................................................... 7-1 7.1 Introduction................................................................................................. 7.2 Starting Fault Finding. ................................................................................ 7.3 Charger Circuit............................................................................................ 7.4 Starting with a Dead Test Tool ................................................................... 7.4.1 Test Tool Completely Dead................................................................. 7.4.2 Test Tool Software Does not Run. ...................................................... 7.4.3 Software Runs, Test Tool not Operative ............................................. 7.5 Miscellaneous Functions............................................................................. 7.5.1 Display and Back Light ....................................................................... 7.5.2 Fly Back Converter.............................................................................. 7.5.3 Slow ADC............................................................................................ 7.5.4 Keyboard.............................................................................................. 7.5.5 Optical Port (Serial RS232 Interface).................................................. 7.5.6 Channel A, Channel B Voltage Measurements ................................... 7.5.7 Channel A Ohms and Capacitance Measurements.............................. 7.5.8 Trigger Functions................................................................................. 7.5.9 Reference Voltages.............................................................................. 7.5.10 Buzzer Circuit .................................................................................... 7.5.11 Reset ROM Circuit (PCB version <8 only)....................................... 7.5.12 RAM Test .......................................................................................... 7.5.13 Power ON/OFF .................................................................................. 7.5.14 PWM Circuit...................................................................................... 7.5.15 Randomize Circuit ............................................................................. 7.6 Loading Software........................................................................................ 7-3 7-4 7-4 7-6 7-6 7-7 7-7 7-8 7-8 7-9 7-10 7-11 7-11 7-12 7-13 7-14 7-15 7-15 7-16 7-16 7-16 7-17 7-17 7-17

8

List of Replaceable Parts................................................................... 8-1 8.1 Introduction................................................................................................. 8.2 How to Obtain Parts.................................................................................... 8.3 Final Assembly Parts .................................................................................. 8.4 Main PCA Unit Parts .................................................................................. 8.5 Main PCA Parts .......................................................................................... 8.6 Accessory Replacement Parts ..................................................................... 8.7 Service Tools............................................................................................... 8-3 8-3 8-4 8-6 8-7 8-24 8-24

9

Circuit Diagrams................................................................................. 9-1 9.1 Introduction................................................................................................. 9-3 9.2 Schematic Diagrams.................................................................................... 9-4

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10

Modifications ...................................................................................... 10-1 10.1 Software modifications ............................................................................. 10-1 10.2 Hardware modifications............................................................................ 10-1

List of Tables

Table 2-1. 2-2. 2-3. 3-1. 3-2. 3-3. 3-4. 3-5. 3-6. 4-1. 4-2. 4-3. 4-4. 4-5. 4-6. 4-7. 4-8. 4-9. 5-1. 5-2. 5-3. 5-4. 7-1. 8-1. 8-2. 8-3. 9-1. 9-2.

Title No Visible Trace Disturbance ............................................................................... Trace Disturbance < 10%...................................................................................... Multimeter Disturbance < 1% ............................................................................... Fluke 123 Main Blocks ......................................................................................... Fluke 123 Operating Modes .................................................................................. Voltage Ranges And Trace Sensitivity ................................................................. Ohms Ranges, Trace Sensitivity, and Current ...................................................... Capacitance Ranges, Current, and Pulse Width.................................................... D-ASIC PWM Signals........................................................................................... Input A,B Frequency Measurement Accuracy Test .............................................. Volts DC Measurement Verification Points ......................................................... Volts AC Measurement Verification Points ......................................................... Input A and B AC Input Coupling Verification Points ......................................... Volts Peak Measurement Verification Points ....................................................... Phase Measurement Verification Points ............................................................... V DC and V AC High Voltage Verification Tests................................................ Resistance Measurement Verification Points........................................................ Capacitance Measurement Verification Points ..................................................... HF Gain Calibration Points Fast ........................................................................... HF Gain Calibration Points Slow.......................................................................... Volt Gain Calibration Points <300V..................................................................... Ohm Gain Calibration Points ................................................................................ Starting Fault Finding............................................................................................ Final Assembly Parts............................................................................................. Main PCA Unit...................................................................................................... Main PCA.............................................................................................................. Parts Location Main PCA Side 1 .......................................................................... Parts Location Main PCA Side 2 ..........................................................................

Page 2-12 2-12 2-12 3-3 3-9 3-18 3-18 3-20 3-29 4-9 4-15 4-16 4-17 4-18 4-18 4-20 4-21 4-23 5-8 5-9 5-12 5-14 7-4 8-4 8-6 8-7 9-4 9-5

List of Figures

Figure 3-1. 3-2. 3-3. 3-4. 3-5. 3-6. 3-7. 3-8. 3-9. 3-10. 3-11. 3-12. 3-13. 4-1. 4-2. 4-3. 4-4. 4-5. 4-6. 4-7. 4-8. 4-9. 4-10. 4-11. 4-12. 4-13. 4-14. 4-15. 5-1. 5-2. 5-3. 5-4. 5-5. 5-6. 5-7.

Title Fluke 123 Block Diagram...................................................................................... Fluke 123 Start-up Sequence, Operating Modes................................................... Power Supply Block Diagram ............................................................................... CHAGATE Control Voltage ................................................................................. Fly-Back Converter Current and Control Voltage ................................................ Fly-Back Converter Block Diagram...................................................................... Back Light Converter Voltages ............................................................................. C-ASIC Block Diagram......................................................................................... Capacitance Measurement..................................................................................... T-ASIC Trigger Section Block Diagram............................................................... Random Repetitive Sampling Mode ..................................................................... Reference Voltage Section .................................................................................... LCD Control.......................................................................................................... Display Pixel Test Pattern ..................................................................................... Menu item selection .............................................................................................. Test Tool Input A to 5500A Scope Output 50 ................................................... Test Tool Input B to 5500A Scope Output 50 ................................................... Test Tool Input A-B to 5500A Normal Output ..................................................... Test Tool Input A-B to 5500A Normal Output for >300V ................................... Test Tool Input A to 5500A Normal Output 4-Wire............................................. Test Tool Input A to TV Signal Generator ........................................................... Test Tool Screen for PAL/SECAM line 622 ........................................................ Test Tool Screen for NTSC line 525..................................................................... Test Tool Screen for PAL/SECAM line 310 ........................................................ Test Tool Screen for NTSC line 262..................................................................... Test Tool Input A to TV Signal Generator Inverted ............................................. Test Tool Screen for PAL/SECAM line 310 Negative Video .............................. Test Tool Screen for NTSC line 262 Negative Video .......................................... Version & Calibration Screen ............................................................................... Display Test Pattern .............................................................................................. HF Gain Calibration Input Connections................................................................ 5500A Scope Output to Input A............................................................................ 5500A Scope Output to Input B ............................................................................ Volt Gain Calibration Input Connections <300V ................................................. Volt Gain Calibration Input Connections 500V....................................................

Page 3-2 3-8 3-9 3-12 3-12 3-13 3-15 3-15 3-19 3-21 3-22 3-24 3-28 4-4 4-6 4-7 4-9 4-11 4-19 4-20 4-23 4-24 4-24 4-25 4-25 4-25 4-26 4-26 5-3 5-6 5-7 5-9 5-11 5-12 5-13

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5-8. 5-9. 5-10. 6-1. 6-2. 6-3. 6-4. 6-5. 7-1. 7-2. 8-1. 8-2. 9-1. 9-2. 9-3. 9-4. 9-5. 9-6. 9-7. 9-8. 9-9. 9-10.

Four-wire Ohms calibration connections .............................................................. Capacitance Gain Calibration Input Connections ................................................. 20 V Supply Cable for Calibration........................................................................ Fluke 123 Main Assembly..................................................................................... Flex Cable Connectors .......................................................................................... Main PCA Unit Assembly..................................................................................... Mounting the display shielding bracket ................................................................ Battery pack installation........................................................................................ Operative Test Tool without Case......................................................................... 20V Supply Cable for Loading Software .............................................................. Fluke 123 Final Assembly..................................................................................... Main PCA Unit...................................................................................................... Circuit Diagram 1, Channel A Circuit................................................................... Circuit Diagram 2, Channel B Circuit................................................................... Circuit Diagram 3, Trigger Circuit........................................................................ Circuit Diagram 4, Digital Circuit......................................................................... Circuit Diagram 4 (cont), Digital Circuit Keyboard ............................................. Circuit Diagram 5, Power Circuit.......................................................................... Main PCA side 1 ................................................................................................... Main PCA side 2 ................................................................................................... Main PCA side 1, PCB version 8 .......................................................................... Main PCA side 2, PCB version 8 ..........................................................................

5-14 5-15 5-16 6-4 6-5 6-7 6-9 6-9 7-3 7-17 8-5 8-6 9-7 9-8 9-9 9-10 9-11 9-12 9-13 9-14 9-15 9-16

Chapter 1

Safety Instructions

Title 1.1 Introduction................................................................................................. 1.2 Safety Precautions....................................................................................... 1.3 Caution and Warning Statements................................................................ 1.4 Symbols....................................................................................................... 1.5 Impaired Safety ........................................................................................... 1.6 General Safety Information.........................................................................

Page 1-3 1-3 1-3 1-3 1-4 1-4

1-1

Safety Instructions 1.1 Introduction

1

1.1 Introduction
Read these pages carefully before beginning to install and use the instrument. The following paragraphs contain information, cautions and warnings which must be followed to ensure safe operation and to keep the instrument in a safe condition.

Warning
Servicing described in this manual is to be done only by qualified service personnel. To avoid electrical shock, do not service the instrument unless you are qualified to do so.

1.2 Safety Precautions
For the correct and safe use of this instrument it is essential that both operating and service personnel follow generally accepted safety procedures in addition to the safety precautions specified in this manual. Specific warning and caution statements, where they apply, will be found throughout the manual. Where necessary, the warning and caution statements and/or symbols are marked on the instrument.

1.3 Caution and Warning Statements
Caution
Used to indicate correct operating or maintenance procedures to prevent damage to or destruction of the equipment or other property.

Warning
Calls attention to a potential danger that requires correct procedures or practices to prevent personal injury.

1.4 Symbols
Read the safety information in the Users Manual Equal potential inputs, connected internally Live voltage Earth DOUBLE INSULATION (Protection Class)

Static sensitive components (black/yellow). Recycling information Disposal information

Conformit Europenne

1-3

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1.5 Impaired Safety
Whenever it is likely that safety has been impaired, the instrument must be turned off and disconnected from line power. The matter should then be referred to qualified technicians. Safety is likely to be impaired if, for example, the instrument fails to perform the intended measurements or shows visible damage.

1.6 General Safety Information
Warning
Removing the instrument covers or removing parts, except those to which access can be gained by hand, is likely to expose live parts and accessible terminals which can be dangerous to life. The instrument shall be disconnected from all voltage sources before it is opened. Capacitors inside the instrument can hold their charge even if the instrument has been separated from all voltage sources. Components which are important for the safety of the instrument may only be replaced by components obtained through your local FLUKE organization. These parts are indicated with an asterisk (*) in the List of Replaceable Parts, Chapter 8.

1-4

Chapter 2

Characteristics

Title 2.1 Introduction................................................................................................. 2.2 Dual Input Oscilloscope.............................................................................. 2.2.1 Vertical ................................................................................................ 2.2.2 Horizontal ............................................................................................ 2.2.3 Trigger ................................................................................................. 2.2.4 Advanced Scope Functions.................................................................. 2.3 Dual Input Meter ......................................................................................... 2.3.1 Input A and Input B ............................................................................. 2.3.2 Input A ................................................................................................. 2.3.3 Advanced Meter Functions.................................................................. 2.4 Miscellaneous ............................................................................................. 2.5 Environmental ............................................................................................. 2.6 Service and Maintenance ............................................................................ 2.7 Safety .......................................................................................................... 2.8 EMC Immunity ...........................................................................................

Page 2-3 2-3 2-3 2-4 2-4 2-5 2-5 2-5 2-8 2-8 2-9 2-10 2-11 2-11 2-12

2-1

Characteristics 2.1 Introduction

2

2.1 Introduction
Performance Characteristics FLUKE guarantees the properties expressed in numerical values with the stated tolerance. Specified non-tolerance numerical values indicate those that could be nominally expected from the mean of a range of identical ScopeMeter test tools. Environmental Data The environmental data mentioned in this manual are based on the results of the manufacturer's verification procedures. Safety Characteristics The test tool has been designed and tested in accordance with Standards ANSI/ISA S82.01-1994, EN 61010-1 (1993) (IEC 1010-1), CAN/CSA-C22.2 No.1010.1-92 (including approval), UL3111-1 (including approval) Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use. Use of this equipment in a manner not specified by the manufacturer may impair protection provided by the equipment.

2.2 Dual Input Oscilloscope
2.2.1 Vertical
Frequency Response DC Coupled: excluding probes and test leads: with STL120 1:1 shielded test leads: with PM8918 10:1 probe: (optional accessory) AC Coupled (LF roll off): excluding probes and test leads with STL120 with PM8918 Rise Time excluding probes and test leads Input Impedance excluding probes and test leads with BB120 with STL120 with PM8918 Sensitivity Display Modes 1 M//12 pF 1 M//20 pF 1 M//225 pF 10 M//15 pF 5 mV to 500 V/div A, -A, B, -B <17.5 ns <10 Hz (-3 dB) <10 Hz (-3dB) <1 Hz (-3 dB) DC to 20 MHz (-3 dB) DC to 12.5 MHz (-3 dB) DC to 20 MHz (-6 dB) DC to 20 MHz (-3 dB)

2-3

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Max. Input Voltage A and B direct or with test leads 600 Vrms with BB120 300 Vrms (For detailed specifications see "2.7 Safety") Max. Floating Voltage from any terminal to ground Resolution Vertical Accuracy Max. Vertical Move Max. Base Line Jump Normal & Single mode 600 Vrms, up to 400Hz 8 bit (1% + 0.05 range/div) 4 divisions After changing time base or sensitivity 0.04 divisions (= 1 pixel)

2.2.2 Horizontal
Scope Modes Ranges Normal: equivalent sampling real time sampling Single (real time) Roll (real time) Equivalent sampling (repetitive signals) Real time sampling: 1 s to 5 ms/div 10 ms to 5 s/div Time Base Accuracy Equivalent sampling Real time sampling Glitch Detection (0.4% +0.04 time/div) (0.1% +0.04 time/div) 40 ns @ 20 ns to 5 ms/div 200 ns @ 10 ms to 60 s/div Glitch detection is always active. 10 divisions Trigger point can be positioned anywhere across the screen. 20 ns to 500 ns/div 1 s to 5 s/div 1 s to 5 s/div 1s to 60 s/div up to 1.25 GS/s 25 MS/s 5 MS/s Normal, Single, Roll

Sampling Rate (for both channels simultaneously)

Horizontal Move

2.2.3 Trigger
Screen Update Source Free Run, On Trigger A, B, EXT EXTernal via optically isolated trigger probe ITP120 (optional accessory)

2-4

Characteristics 2.3 Dual Input Meter

2

Sensitivity A and B @ DC to 5 MHz @ 25 MHz @ 40 MHz Voltage level error Slope Video on A Modes Standards Polarity Sensitivity 0.5 divisions or 5 mV 1.5 divisions 4 divisions 0.5 div. max. Positive, Negative Interlaced video signals only Lines, Line Select PAL , NTSC, PAL+, SECAM Positive, Negative 0.6 divisions sync.

2.2.4 Advanced Scope Functions
Display Modes Normal Smooth Envelope Captures up to 40 ns glitches and displays analog-like persistence waveform. Suppresses noise from a waveform. Records and displays the minimum and maximum of waveforms over time.

Auto Set Continuous fully automatic adjustment of amplitude, time base, trigger levels, trigger gap, and hold-off. Manual override by user adjustment of amplitude, time base, or trigger level.

2.3 Dual Input Meter
The accuracy of all measurements is within (% of reading + number of counts) from 18 C to 28 C. Add 0.1x (specific accuracy) for each C below 18 C or above 28 C. For voltage measurements with 10:1 probe, add probe uncertainty +1%. More than one waveform period must be visible on the screen.

2.3.1 Input A and Input B
DC Voltage (VDC) Ranges Accuracy Turnover Normal Mode Rejection (SMR) Common Mode Rejection (CMRR) Full Scale Reading Move influence 500 mV, 5V, 50V, 500V, 1250V (0.5% +5 counts) 12 counts >60 dB @ 50 or 60 Hz 1% >100 dB @ DC >60 dB @ 50, 60, or 400 Hz 5000 counts 6 counts max.

2-5

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True RMS Voltages (VAC and VAC+DC) Ranges Accuracy for 5 to 100% of range DC coupled: DC to 60 Hz (VAC+DC) 1 Hz to 60 Hz (VAC) AC or DC coupled: 60 Hz to 20 kHz 20 kHz to 1 MHz 1 MHz to 5 MHz 5 MHz to 12.5 MHz 5 MHz to 20 MHz AC coupled with 1:1 (shielded) test leads: 60 Hz (6 Hz with 10:1 probe) 50 Hz (5 Hz with 10:1 probe) 33 Hz (3.3 Hz with 10:1 probe) 10 Hz (1 Hz with 10:1 probe) DC Rejection (only VAC) Common Mode Rejection (CMRR) Full Scale Reading (1% +10 counts) (1% +10 counts) (2.5% +15 counts) (5% +20 counts) (10% +25 counts) (30% +25 counts) (30% +25 counts), excluding test leads or probes -1.5% -2% -5% -30% >50 dB >100 dB @ DC >60 dB @ 50, 60, or 400 Hz 5000 counts The reading is independent of any signal crest factor. 6 counts max. Max peak, Min peak, or pk-to-pk 500 mV, 5V, 50V, 500V, 1250V 5% of full scale 10% of full scale 500 counts 1Hz, 10Hz, 100Hz, 1 kHz, 10 kHz, 100 kHz,1 MHz, 10 MHz, 40 MHz 15Hz (1Hz) to 30 MHz (0.5% +2 counts) (1.0% +2 counts) (2.5% +2 counts) 10 000 counts 500 mV, 5V, 50V, 500V, 1250V

Move influence Peak Modes Ranges Accuracy: Max peak or Min peak Peak-to-Peak Full Scale Reading Frequency (Hz) Ranges Frequency Range for Continuous Autoset Accuracy: @1Hz to 1 MHz @1 MHz to 10 MHz @10 MHz to 40 MHz Full Scale Reading

2-6

Characteristics 2.3 Dual Input Meter

2

Duty Cycle (DUTY) Range Frequency Range for Continuous Autoset Accuracy: @1Hz to 1 MHz @1 MHz to 10 MHz @10 MHz to 40 MHz Resolution Pulse Width (PULSE) Frequency Range for Continuous Autoset Accuracy: @1Hz to 1 MHz @1 MHz to 10 MHz @10 MHz to 40 MHz Full Scale reading Amperes (AMP) Ranges Scale Factor Accuracy Temperature (TEMP) Range Scale Factor Accuracy Decibel (dB) 0 dBV 0 dBm (600 /50) dB on Full Scale Reading Crest Factor (CREST) Range Accuracy Full Scale Reading Phase Modes Range Accuracy Resolution A to B, B to A 0 to 359 degrees (1 degree +1 count) 1 degree
2-7

2% to 98% 15Hz (1Hz) to 30 MHz (0.5% +2 counts) (1.0% +2 counts) (2.5% +2 counts) 0.1% 15Hz (1Hz) to 30 MHz (0.5% +2 counts) (1.0% +2 counts) (2.5% +2 counts) 1000 counts with optional current probe same as VDC, VAC, VAC+DC, or PEAK 1 mV/A, 10 mV/A, 100 mV/A, and 1 V/A same as VDC, VAC, VAC+DC, or PEAK (add current probe uncertainty) with optional temperature probe 200 C/div (200 F/div) 1 mV/C and 1 mV/F as VDC (add temperature probe uncertainty) 1V 1 mW, referenced to 600 or 50 VDC, VAC, or VAC+DC 1000 counts 1 to 10 (5% +1 count) 100 counts

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2.3.2 Input A
Ohm () Ranges Accuracy Full Scale Reading 500 to 5 M 30 M Measurement Current Open Circuit Voltage Continuity (CONT) Beep Measurement Current Detection of shorts of Diode Maximum Voltage: @0.5 mA @open circuit Accuracy Measurement Current Polarity Capacitance (CAP) Ranges Accuracy Full Scale Reading Measurement Current Measurement principle 50 nF, 500 nF, 5 F, 50 F, 500 F (2% +10 counts) 5000 counts 5 A to 0.5 mA, increases with increasing ranges Dual slope integrating measurement with parasitic serial and parallel resistance cancellation. >2.8V <4V (2% +5 counts) 0.5 mA + on input A, - on COM 30 5 in 50 range 0.5 mA 1 ms 500, 5 k, 50 k, 500 k, 5 M, 30 M (0.6% +5 counts) 5000 counts 3000 counts 0.5 mA to 50 nA decreases with increasing ranges <4V

2.3.3 Advanced Meter Functions
Zero Set Fast/Normal/Smooth Meter settling time Fast Meter settling time Normal Meter settling time Smooth Set actual value to reference 1s @ 1s to 10 ms/div 2s @ 1s to 10 ms/div 10s @ 1s to 10 ms/div

2-8

Characteristics 2.4 Miscellaneous

2

Touch Hold (on A)

Captures and freezes a stable measurement result. Beeps when stable. Touch Hold works on the main meter reading , with threshholds of 1 Vpp for AC signals and 100mV for DC signals. Graphs meter readings of the Min and Max values from 15 s/div (120 seconds) to 2 days/div (16 days) with time and date stamp. Automatic vertical scaling and time compression. Displays the actual and Minimum, Maximum, or average (AVG) reading. Possible by using attenuation keys.

TrendPlot

Fixed Decimal Point

2.4 Miscellaneous
Display Size Resolution Waveform display: Vertical Horizontal Backlight Power External: Input Voltage Power Input Connector Internal: Battery Power Operating Time Charging Time Allowable ambient temperature during charging Memory Number of Screens Number of User Setups Mechanical Size Weight 232 x 115 x 50 mm (9.1 x 4.5 x 2 in) 1.1 kg (2.5 lbs), including battery pack. 2 10 via Power Adapter PM8907 10 to 21V DC 5W typical 5 mm jack Rechargeable Ni-Cd 4.8V 4 hours with bright backlight 5 hours with dimmed backlight 4 hours with test tool off 12 hours with test tool on 12 hours with refresh cycle 0 to 45 C (32 to 113 F) 72 x 72 mm (2.83 x 2.83 in) 240 x 240 pixels 8 divisions of 20 pixels 9.6 divisions of 25 pixels Cold Cathode Fluorescent (CCFL)

2-9

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Interface To Printer

RS-232, optically isolated supports Epson FX, LQ, and HP Deskjet, Laserjet, and Postscript Serial via PM9080 (optically isolated RS232 adapter/cable, optional). Parallel via PAC91 (optically isolated print adapter cable, optional). Dump and load settings and data. Serial via PM9080 (optically isolated RS232 adapter/cable, optional), using SW90W (FlukeView software for Windows).

To PC

2.5 Environmental
Environmental Temperature Operating Storage Humidity Operating: @0 to 10 C (32 to 50 F) @10 to 30 C (50 to 86 F) @30 to 40 C (86 to 104 F) @40 to 50 C (104 to 122 F) Storage: @-20 to 60 C (-4 to 140 F) Altitude Operating 4.5 km (15 000 feet) Max. Input and Floating Voltage 600 Vrms up to 2 km, linearly derating to 400 Vrms @ 4.5 km 12 km (40 000 feet) max. 3g max. 30g MIL28800E, Class 3, 3.7.7 & 4.5.6.1 MIL28800E, Class 3, 3.7.8.2 & 4.5.6.2.2. Structural parts meet 48 hours 5% salt solution test. EN 50081-1 (1992): EN55022 and EN60555-2 EN 50082-2(1992): IEC1000-4-2, -3, -4, -5 (see also Section 2.8, Tables 2-1 to 2-3) IP51, ref: IEC529 noncondensing 95% 75% 45% noncondensing 0 to 50 C (32 to 122 F) -20 to 60 C (-4 to 140 F) MIL 28800E, Type 3, Class III, Style B

Storage Vibration Shock Fungus Resistance Salt Exposure

Electromagnetic Compatibility (EMC) Emission Immunity Enclosure Protection

2-10

Characteristics 2.6 Service and Maintenance

2

2.6 Service and Maintenance
Calibration Interval 1 Year

2.7 Safety
Designed for measurements on 600 Vrms Category III Installations, Pollution Degree 2, per: ANSI/ISA S82.01-1994 EN61010-1 (1993) (IEC1010-1) CAN/CSA-C22.2 No.1010.1-92 (including approval) UL3111-1 (including approval) Max. Input Voltage Input A and B Direct on input or with leads With Banana-to-BNC Adapter BB120 Max. Floating Voltage from any terminal to ground 600 Vrms up to 400Hz 600 Vrms. For derating see Figure 2-1. 300V rms. For derating see Figure 2-1.

ST8112.CGM

Figure 2-1. Maximum Input Voltage vs Frequency

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2.8 EMC Immunity
The Fluke 123, including standard accessories, conforms with the EEC directive 89/336 for EMC immunity, as defined by IEC1000-4-3, with the addition of tables 2-1 to 2-3. Trace Disturbance with STL120 See Table 2-1 and Table 2-2.

Table 2-1. No Visible Trace Disturbance No visible disturbance Frequency range 10 kHz to 27 MHz Frequency range 27 MHz to 1 GHz E= 3 V/m 50 mV/div to 500 V/div 50 mV/div to 500 V/div E= 10 V/m 500 mV/div to 500 V/div 50 mV/div to 500 V/div

Table 2-2. Trace Disturbance < 10% Disturbance less than 10% of full scale Frequency range 10 kHz to 27 MHz Frequency range 2 MHz to 1 GHz (-): no visible disturbance Test tool ranges not specified in Table 2-1 and Table 2-2 may have a disturbance of more than 10% of full scale. E= 3 V/m 10 mV/div to 20 mV/div 5 mV/div to 20 mV/div E= 10 V/m 50 mV/div to 200 mV/div -

Multimeter disturbance

See Table 2-3.

VDC, VAC, and VAC+DC with STL 120 and short ground lead OHM, CONT, DIODE, and CAP with STL120 and black test lead to COM
Table 2-3. Multimeter Disturbance < 1%

Disturbance less than 1% of full scale Frequency range 10 kHz to 27 MHz VDC, VAC, VAC+DC OHM, CONT, DIODE CAP Frequency range 27 MHz to 1 GHz VDC, VAC, VAC+DC OHM, CONT, DIODE CAP

E= 3 V/m 500 mV to 1250V 500 to 30 M 50 nF to 500 F 500 mV to 1250V 500 to 30 M 50 nF to 500 F

E= 10 V/m 500 mV to 1250V 500 to 30 M 50 nF to 500 F 500 mV to 1250V 500 to 30 M 50 nF to 500 F

Test tool ranges not specified in Table 2-3 may have a disturbance of more than 10% of full scale.

2-12

Chapter 3

Circuit Descriptions

Title 3.1 Introduction................................................................................................. 3.2 Block Diagram ............................................................................................ 3.2.1 Channel A, Channel B Measurement Circuits..................................... 3.2.2 Trigger Circuit ..................................................................................... 3.2.3 Digital Circuit ...................................................................................... 3.2.4 Power Circuit ....................................................................................... 3.2.5 Start-up Sequence, Operating Modes .................................................. 3.3 Detailed Circuit Descriptions...................................................................... 3.3.1 Power Circuit ....................................................................................... 3.3.2 Channel A - Channel B Measurement Circuits ................................... 3.3.3 Trigger Circuit ..................................................................................... 3.3.4 Digital Circuit ......................................................................................

Page 3-3 3-3 3-4 3-4 3-5 3-6 3-7 3-9 3-9 3-15 3-20 3-25

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ST7965.EPS

Figure 3-1. Fluke 123 Block Diagram

3-2

Circuit Descriptions 3.1 Introduction

3

3.1 Introduction
Section 3.2 describes the functional block diagram shown in Figure 3-1. It provides a quick way to get familiar with the test tool basic build-up. Section 3.3 describes the principle of operation of the test tool functions in detail, on the basis of the circuit diagrams shown in Figures 9-1 to 9-5. For all measurements, input signals are applied to the shielded input banana jackets. Traces and readings are derived from the same input signal samples. So readings are related to the displayed readings.

3.2 Block Diagram
In the overall block diagram Figure 3-1, the test tool is divided in five main blocks. Each block represents a functional part, build up around an Application Specific Integrated Circuit (ASIC). A detailed circuit diagram of each block is shown in Section 9. See Table 3-1. for an overview of the blocks in which the test tool is broken down, the main block function, the ASIC name, and the applicable circuit diagram.
Table 3-1. Fluke 123 Main Blocks Block CHANNEL A CHANNEL B TRIGGER Main Functions Input A signal (V--F) conditioning Input B signal (V) conditioning Trigger selection and conditioning Current source for resistance, capacitance, continuity, and diode measurements AC/DC input coupling and /F relay control Voltage reference source DIGITAL Analog to Digital Conversion Acquisition of ADC samples Micro controller (P-ROM-RAM) Keyboard- and LCD control POWER Power supply, battery charger LCD back light voltage converter Optical interface input P(ower)-ASIC OQ0256 Figure 9-5 D(igital)-ASIC MOT0002 Figure 9-4 ASIC C(hannel)-ASIC OQ0258 C(hannel)-ASIC OQ0258 T(rigger)-ASIC OQ0257 Circuit Diagram Figure 9-1 Figure 9-2 Figure 9-3

All circuits, except the LCD unit and the KEYBOARD, are located on one Printed Circuit Board (PCB), called the MAIN PCB. The ASIC's are referred to as C-ASIC (Channel ASIC), T-ASIC (Trigger ASIC), P-ASIC (Power ASIC), and D-ASIC (Digital ASIC).

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3.2.1 Channel A, Channel B Measurement Circuits
The Channel A and Channel B circuit are similar. The only difference is that Channel A can do all measurements, whereas Channel B does not provide resistance, diode, and capacitance measurements. Volts, and derived measurements (e.g. current with optional probe) The input voltage is supplied to the C-ASIC, via the LF and HF path. The C-ASIC converts (attenuates, amplifies) the input signal to a normalized output voltage ADCA/ADC-B, which is supplied to the Analog to Digital Converters (ADC-A and ADC-B) on the DIGITAL part. The D-ASIC acquires the digital samples to build the trace, and to calculate readings. For the HF and LF attenuation section of the C-ASIC some external components are required: the HF DECade ATTenuator and LF DECade ATTenuator section. Resistance, continuity, and diode measurements (Input A only) The T-ASIC supplies a current via the /F relays to the unknown resistance Rx, connected to the Input A and the COM input jacket. The voltage drop across Rx is measured as for voltage measurements. Capacitance measurements (Input A only) The T-ASIC supplies a current via the /F relays to the unknown capacitance Cx, connected to the Input A and the COM input jacket. Cx is charged and discharged by this current. The C-ASIC converts the charging time and the discharging time into a pulse width signal. This signal is supplied to the T-ASIC via the C-ASIC trigger output TRIG-A. The T-ASIC shapes and levels the signal, and supplies the resulting pulse width signal ALLTRIG to the D-ASIC. The D-ASIC counts the pulse width and calculates the capacitance reading. When the capacitance function is selected no other measurement or wave form display is possible. There is only a numeric readout of the capacitance value. Frequency, pulse width, and duty cycle measurements The input voltage is measured as described above. From the ADC samples to built the trace, also the frequency, pulse width, and duty cycle of the input signal are calculated. Miscellaneous Control of the C-ASIC, e.g. selecting the attenuation factor, is done by the D-ASIC via the SDAT and SCLK serial communication lines. An offset compensation voltage and a trace position control voltage are provided by the D-ASIC via the APWM bus. The C-ASIC's also provide conditioned input voltages on the TRIG-A/TRIG-B line. These voltages can be selected as trigger source by the T-ASIC.

3.2.2 Trigger Circuit
The T ASIC selects one of the possible trigger sources TRIG-A (Input A) or TRIG-B (Input B). For TV triggering the selected trigger source signal is processed via the Sync(hronization) Pulse Separator circuit (TVOUT-TVSYNC lines). Two adjustable trigger levels are supplied by the D-ASIC via the PWM FILTERS (TRIGLEV1 and TRIGLEV2 line). Depending on the selected trigger conditions (- source, - level, - edge, - mode), the T-ASIC generates the final trigger signal TRIGDT, which is supplied to the D-ASIC.
3-4

Circuit Descriptions 3.2 Block Diagram

3

Note External triggers, supplied via the optical interface RXDA line, are buffered by the P-ASIC, and then supplied to the D-ASIC (RXD signal). The TRIG-A input is also used for capacitance measurements, as described in Section 3.2.1. The T-ASIC includes a constant current source for resistance and capacitance measurements. The current is supplied via the GENOUT output and the /F relays to the unknown resistance Rx or capacitance Cx connected to Input A. The SENSE signal senses the voltage across Cx and controls a CLAMP circuit in the T-ASIC. This circuit limits the voltage on Input A at capacitance measurements. The protection circuit prevents the T-ASIC from being damaged by voltages supplied to the input during resistance or capacitance measurements. For probe adjustment, a voltage generator circuit in the T-ASIC can provide a square wave voltage via the GENOUT output to the Input A connector. The T-ASIC contains opamps to derive reference voltages from a 1.23V reference source. The gain factors for these opamps are determined by resistors in the REF GAIN circuit. The reference voltages are supplied to various circuits. The T-ASIC also controls the Channel A and B AC/DC input coupling relays, and the /F relays. Control data for the T-ASIC are provided by the D-ASIC via the SDAT and SCLK serial communication lines.

3.2.3 Digital Circuit
The D-ASIC includes a micro processor, ADC sample acquisition logic, trigger processing logic, display and keyboard control logic, I/O ports, and various other logic circuits. The instrument software is stored in the FlashROM, the RAM is used for temporary data storage. The RESET ROM circuit controls the operating mode of the FlashROM (reset, programmable, operational). For Voltage and Resistance measurements, the conditioned Input A/ Input B voltages are supplied to the ADC-A and ADC-B ADC. The voltages are sampled, and digitized by the ADC's. The output data of the ADC's are acquired and processed by the D-ASIC. For capacitance measurements, the ALLTRIG signal generated by the T-ASIC, is used. The D-ASIC counts the ALLTRIG signal pulse width, which is proportional to the unknown capacitance. The DPWM-BUS (Digital Pulse Width Modulation) supplies square wave signals with a variable duty cycle to the PWM FILTERS circuit (RC filters). The outgoing APWMBUS (Analog PWM) provides analog signals of which the amplitude is controlled by the D-ASIC. These voltages are used to control e.g. the trace positions (C-ASIC), the trigger levels (T-ASIC), and the battery charge current (P-ASIC). In random sampling mode (time base faster than 1 s/div.), a trace is built-up from several acquisition cycles. During each acquisition, a number of trace samples are placed as pixels in the LCD. The RANDOMIZE circuit takes care that the starting moment of each acquisition cycle (trigger release signal HOLDOFF goes low) is random. This prevents that at each next acquisition the trace is sampled at the same time positions, and that the displayed trace misses samples at some places on the LCD. The D-ASIC supplies control data and display data to the LCD module. The LCD module is connected to the main board via connector X453. It consists of the LCD, LCD
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drivers, and a fluorescent back light lamp. As the module is not repairable, no detailed description and diagrams are provided. The back light supply voltage is generated by the back light converter on the POWER part. The keys of the keyboard are arranged in a matrix. The D-ASIC drives the rows and scans the matrix. The contact pads on the keyboard foil are connected to the main board via connector X452. The ON-OFF key is not included in the matrix, but is sensed by a logic circuit in the D-ASIC, that is active even when the test tool is turned off. Via the PROBE-A and PROBE-B lines, connected to the Input A and Input B banana shielding, the D-ASIC can detect if a probe is connected. This function is not supported by the Fluke 123 software. The D-ASIC sends commands to the C-ASICs and T-ASIC via the SCLK and SDAT serial control lines, e.g. to select the required trigger source. Various I/O lines are provided, e.g. to control the BUZZER and the Slow-ADC (via the SADC bus.

3.2.4 Power Circuit
The test tool can be powered via the power adapter, or by the battery pack. If the power adapter is connected, it powers the test tool and charges the battery via the CHARGER-CONVERTER circuit. The battery charge current is sensed by sense resistor Rs (signal IBAT). It is controlled by changing the output current of the CHARGER-CONVERTER (control signal CHAGATE). If no power adapter is connected, the battery pack supplies the VBAT voltage. The VBAT voltage powers the P-ASIC, and is also supplied to the FLY BACK CONVERTER (switched mode power supply). If the test tool is turned on, the FLY BACK CONVERTER generates supply voltages for various test tool circuits. The +3V3GAR supply voltage powers the D-ASIC, RAM and ROM. If the test tool is turned off, the battery supplies the +3V3GAR voltage via transistor V569. This transistor is controlled by the P-ASIC. So when the test tool is turned off, the D-ASIC can still control the battery charging process (CHARCURR signal), the real time clock, the on/off key, and the serial RS232 interface (to turn the test tool on). To monitor and control the battery charging process, the P-ASIC senses and buffers various battery signals, as e.g. temperature (TEMP), voltage (BATVOLT), current (IBAT). Via the SLOW ADC various analog signals can be measured by the D-ASIC. Involved signals are: battery voltage (BATVOLT), battery type (IDENT), battery temperature (TEMP), battery current (BATCUR) LCD temperature (LCDTEMP, from LCD unit), and 3 test output pins of the C-ASIC's, and the T-ASIC (DACTEST). The signals are used for control and test purposes. The BACK LIGHT CONVERTER generates the 400V ! supply voltage for the LCD fluorescent back light lamp. If the lamp is defective a 1.5 kV voltage can be present for 0.2 second maximum. The brightness is controlled by the BACKBRIG signal supplied by the D-ASIC. Serial communication with a PC or printer is possible via the RS232 optically isolated interface. This interface is also used for external trigger input using the Isolated Trigger Probe. The P-ASIC buffers the received data line (RXDA) and supplies the buffered data (RXD) to the D-ASIC. The transmit data line TXD is directly connected to the DASIC.

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Circuit Descriptions 3.2 Block Diagram

3

A linear regulator in the P-ASIC derives a +12V voltage from the power adapter voltage. The +12V is used as programming voltage for the Flash EPROM on the Digital part.

3.2.5 Start-up Sequence, Operating Modes
The test tool sequences through the following steps when power is applied (see also Figure 3-2): 1. The P-ASIC is directly powered by the battery or power adapter voltage VBAT. Initially the Fly Back Converter is off, and the D-ASIC is powered by VBAT via transistor V569 (+3V3GAR). If the voltage +3V3GAR is below 3.05V, the P-ASIC keeps its output signal VGARVAL (supplied to the D-ASIC) low, and the D-ASIC will not start up. The test tool is not working, and is in the Idle mode. 2. If the voltage +3V3GAR is above 3.05V, the P-ASIC makes the line VGARVAL high, and the D-ASIC will start up. The test tool is operative now. If it is powered by batteries only, and not turned on, it is in the Off mode. In this mode the DASIC is active: the real time clock runs, and the ON/OFF key is monitored to see if the test tool will be turned on. 3. If the power adapter is connected (P-ASIC output MAINVAL high), and/or the test tool is turned on, the embedded D-ASIC program, called mask software, starts up. The mask software checks if valid instrument software is present in the Flash ROM's. If not, the test tool does not start up and the mask software continues running until the test tool is turned off, or the power is removed. This is called the Mask active mode. The mask active mode can also be entered by pressing the ^ and > key when turning on the test tool.

If valid instrument software is present, one of the following modes will become active: Charge mode The Charge mode is entered when the test tool is powered by the power adapter, and is turned off. The FLY-BACK CONVERTER is off. The CHARGERCONVERTER charges the batteries (if installed). Operational & Charge mode The Operational & Charge mode is entered when the test tool is powered by the power adapter, and is turned on. The FLY-BACK CONVERTER is on, the CHARGER-CONVERTER supplies the primary current. If batteries are installed, they will be charged. In this mode a battery refresh (see below) can be done. Operational mode The Operational mode is entered when the test tool is powered by batteries only, and is turned on. The FLY-BACK CONVERTER is on, the batteries supply the primary current. If the battery voltage (VBAT) drops below 4V when starting up the fly back converter, the Off mode is entered.

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Battery Refresh In the following situations the batteries will need a deep discharge-full charge cycle, called a "refresh": every 50 not-full discharge/charge cycles, or each 6 months. This prevents battery capacity loss due to the memory effect. after the battery has been removed, as the test tool does not know the battery status then.

The user will be prompted for this action when he turns the test tool on, directly following the start up screen. A refresh cycle takes 16 hours maximum, depending on the battery status. It can be started via the keyboard (USER OPTIONS, F1, activate refresh) if the test tool is on, and the power adapter is connected. During a refresh, first the battery is completely charged, then it is completely discharged (the test tool is powered by the battery only, and the power adapter must be connected!), and then it is completely charged again.
VGARVAL=L

Idle mode

VGARVAL=H

Off mode
TURN ON or MAINVAL=H Flash ROM NOT OK

Mask StartUp
Flash ROM OK

OR
&

Mask Active mode

TURN OFF

& TURN ON

Extern StartUp Software
TURN ON & BATTVOLT > 4 & MAINVAL=L

MAINVAL=L & (TURN OFF or BATTVOLT<4V)

TURN OFF&MAINVAL=H

TURN ON & MAINVAL=H MAINVAL=H TURN OFF

Operational Mode

MAINVAL=L

Operational & Charge Mode

Charge Mode

TURN ON MAINVAL=L

BATTVOLT < 4V or AutoShutDown or TURN OFF

Battery refresh

Figure 3-2. Fluke 123 Start-up Sequence, Operating Modes

Table 3-2 shows an overview of the test tool operating modes.
3-8

Circuit Descriptions 3.3 Detailed Circuit Descriptions
Table 3-2. Fluke 123 Operating Modes Mode Idle mode Off mode Mask active mode Charge mode Operational & Charge mode Operational mode Conditions No power adapter and no battery No power adapter connected, battery installed, test tool off No valid instrument software, or ^ and > key pressed when turning on Power adapter connected and test tool off Power adapter connected and test tool on No power adapter connected, battery installed, and test tool on no activity P-ASIC & D-ASIC powered (VBAT & +3V3GAR). Mask software runs Batteries will be charged Test tool operational, and batteries will be charged Test tool operational, powered by batteries Remark

3

3.3 Detailed Circuit Descriptions
3.3.1 Power Circuit
The description below refers to circuit diagram Figure 9-5. Power Sources , Operating Modes Figure 3-3 shows a simplified diagram of the power supply and battery charger circuit.
SUPPLY FLY BACK CONVERTER VBAT CHARGER/CONVERTER V506 L501 R503 VBATSUP R513 VBATHIGH VBATT V503 C503 R512 R504 R506 R507 TEMP TEMPHI IBATP 60 7 3 5 4 9 Amplify Level shift V569 +3V3GAR

FROM POWER ADAPTER R501

69

66 64 VGARVAL Vref 78 BATVOLT 79 BATTEMP

77 BATCUR

CHAGATE CHASENSN CHASENSP R514 IIMAXCHA VCHDRIVE R516 VADALOW VADAPTER

16 14 15 6 19 8 20

CONTROL

80 CHARCURR

100kHz

COSC 43 C553

R502

12 linear regulator linear regulator

V565 V566

MAINVAL

C502

18 P7VCHA C507 22 +12V

POWER ASIC
Figure 3-3. Power Supply Block Diagram

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As described in Section 3.2.5, the test tool operating mode depends on the connected power source. The voltage VBAT is supplied either by the power adapter via V506/L501, or by the battery pack. It powers a part of the P-ASIC via R503 to pin 60 (VBATSUP). If the test tool is off, the Fly Back Converter is off, and VBAT powers the D-ASIC via transistor V569 (+3V3GAR). This +3V3GAR voltage is controlled and sensed by the P-ASIC. If it is NOT OK (<3.05V), the output VGARVAL (pin 64) is low. The VGARVAL line is connected to the D-ASIC, and if the line is low, the D-ASIC is inactive: the test tool is in the Idle mode. A low VGARVAL line operates as a reset for the D-ASIC. If VGARVAL is high (+3V3GAR > 3.05V), the D-ASIC becomes active, and the Off mode is entered. The D-ASIC monitors the P-ASIC output pin 12 MAINVAL, and the test tool ON/OFF status. By pressing the ON/OFF key, a bit in the D-ASIC, indicating the test tool ON/OFF status is toggled. If neither a correct power adapter voltage is supplied (MAINVAL is low), or the test tool is turned on, the Off mode will be maintained. If a correct power adapter voltage is supplied (MAINVAL high), or if the test tool is turned on, the mask software starts up. The mask software checks if valid instrument software is present. If not, e.g. no instrument firmware is loaded, the mask software will keep running, and the test tool is not operative: the test tool is in the Mask active state. For test purposes the mask active mode can also be entered by pressing the ^ and > key when the test tool is turned on. If valid software is present, one of the three modes Operational, Operational & Charge or Charge will become active. The Charger/Converter circuit is active in the Operational & Charge and in the Charge mode. The Fly back converter is active in the Operational and in the Operational & Charge mode. Charger/Converter (See Also Figure 3-3.) The power adapter powers the Charge Control circuit in the P-ASIC via an internal linear regulator. The power adapter voltage is applied to R501. The Charger/Converter circuit controls the battery charge current. If a charged battery pack is installed, VBAT is approximately +4.8V. If no battery pack is installed, VBAT is approximately +15V. The voltage VBAT is supplied to the battery pack, to the P-ASIC, to the Fly Back Converter, and to transistor V569. The FET control signal CHAGATE is a 100 kHz square wave voltage with a variable duty cycle , supplied by the P-ASIC Control circuit. The duty cycle determines the amount of energy loaded into L501/C503. By controlling the voltage VBAT, the battery charge current can be controlled. The various test tool circuits are supplied by the Fly Back Converter, and/or V569. Required power adapter voltage The P-ASIC supplies a current to reference resistor R516 (VADALOW pin 8). It compares the voltage on R516 to the power adapter voltage VADAPTER on pin 20 (supplied via R502, and attenuated in the P-ASIC). If the power adapter voltage is below 10V, the P-ASIC output pin 12, and the line MAINVAL, are low. This signal on pin 12 is also supplied to the P-ASIC internal control circuit, which then makes the CHAGATE signal high. As a result FET V506 becomes non-conductive, and the Charger/Converter is off. Battery charge current control The actual charge current is sensed via resistors R504-R506-507, and filter R509-C509, on pin 9 of the P-ASIC (IBATP). The sense voltage is supplied to the control circuit. The required charge current information is supplied by the D-ASIC via the CHARCUR
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Circuit Descriptions 3.3 Detailed Circuit Descriptions

3

line and filter R534-C534 to pin 80. A control loop in the control circuit adjusts the actual charge current to the required value. The filtered CHARCUR voltage range on pin 80 is 0... 2.7V for a charge current from 0.5A to zero. A voltage of 0V complies to 0.5A (fast charge), 1.5V to 0.2A (top off charge), 2.3V to 0.06A (trickle charge), and 2.7V to 0A (no charge). If the voltage is > 3 Volt, the charger converter is off (V506 permanently non-conductive). The D-ASIC derives the required charge current value from the battery voltage VBAT. The P-ASIC converts this voltage to an appropriate level and supplies it to output pin 78 (BATVOLT). The D-ASIC measures this voltage via the Slow ADC. The momentary value, and the voltage change as a function of time (-dV/dt), are used as control parameters. Charging process If the battery voltage drops below 5.2V, and the battery temperature is between 10 and 45C, the charge current is set to 0.5A (fast charge). From the battery voltage change dV/dt the D-ASIC can see when the battery is fully charged, and stop fa