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Fluke 8842a instruction manual Digital Controller Block Diagram

Models: 8842a

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8842A

Instruction Manual

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Figure 5-13. Digital Controller Block Diagram

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Fluke 8842a instruction manual Digital Controller Block Diagram

Contents

8842A Page Table of Contents Remote Programming 8842AMeasurement Tutorial Maintenance List of Replaceable Parts Schematic Diagrams List of Tables 805-7 List of Figures 805-8 IEEE-488 Interface PCA, Option True RMS AC PCA, Option Xii Introduction and Specifications Introduction Options and Accessories8842A Digital Multimeter Specifications True RMS AC Voltage Option 8842A-09 Peak NM SignalRate FilterFor Inputs FrequencyFundamental Frequency Crest FactorFull Scale 5½ Digits Current½ Digits Through Unknown Range Full Scale Resolution Current ½ DigitsHours 23±1C Function Rate Power Line FREQUECNCY1Automatic Settling Time Delay AutorangingConversion Time ms 50 Hz 60 Hz 400 Hz External Trigger Timing CharacteristicsGeneral PowerOperating Instructions Installing the Power-Line Fuse InstallationConnecting to Line Power Rack Mounting Kits Adjusting the HandlePower-Up Features Operating FeaturesFront and Rear Panel Features Operating Features Local button causes the 8842A to display its Rear Panel Features Error Messages Display FeaturesMeaning Error Code Error CodeAutorange Diagnostic Self-TestsOverrange Indication RangingTriggering Continuous Trigger ModeExternal Trigger Mode Manual RangeExternal Trigger Input Option -05 Only Automatic Settling Time DelaySample Complete Output Option -05 Only Measuring Current Making MeasurementsInput Overload Protection Limits Measuring Voltage and ResistanceOffset Measurements Measuring Voltage and Resistance External Cleaning8842A Remote Programming Measurement Data Overrange Indication Error Messages Capabilities BUS SET-UP ProcedureIEEE-488 Address Selection AN Overview of Remote OperationAN Overview of Remote Operation ExampleExplanation DEVICE-DEPENDENT Command SETDEVICE-DEPENDENT Command SET Device-Dependent Command Set Cn Calibration Commands Bn Offset CommandsDn Display Commands Get Commands Fn Function CommandsMeaning Command Output String13. G1 Get SRQ Mask 12. G0 Get Instrument Configuration14. G2 Get Calibration Prompt 16. G4 Get Calibration Status 15. G3 Get User-Defined Message17. G5 Get IAB Status 19. G7 Get Error Status18. G6 Get YW Status 20. G8 Get Instrument Identification Numeric Entry CommandPut Commands 23. P0 Put Instrument Configuration25. P2 Put Calibration Value 24. P1 Put SRQ MaskSn Reading Rate Commands Rn Range Commands26. P3 Put User-Defined Message Trigger Selection Logic Diagram Tn Trigger Mode Commands33. Z0 Self-Test Command Wn Terminator Commands31. X0 Clear Error Register Command Yn Suffix Commands35. ? Single-Trigger Command Device-Clear CommandInput Syntax Input Processing DefinitionsDEVICE-DEPENDENT Messages ERROR-PRODUCING CharactersInterface Messages Incorrect example Syntax RulesLoading Output Data Output DataMeasurement Data Numeric Data and Error MessagesOverrange Indication Error Messages Types of Output DataOutput Priority Error MessagesOverrange Indication Status DataSerial Poll Register Service RequestsSet SRQ MaskInterface Messages Universal CommandsAddress Messages Addressed Commands TALK-ONLY ModeRemote Calibration Immediate Mode CommandsTiming Considerations Example Programs Immediate-Mode Commands for Various ControllersExample Programs 10. Example Program Taking Readings with Local Control 11. Example Program Using the Serial Poll Register 12. Example Program Record Errors During Selftest 13. Example Programs Using the IBM PC 14. Example Programs Using the IBM PC F3-1402.wmf F3-1403.wmf F3-1404.wmf F3-1405.wmf F3-1406.wmf F3-1407.wmf F3-1408.wmf F3-1409.wmf F3-1410.wmf F3-1411.wmf ASCII/IEEE Std 488-1978 Bus Codes 8842A Measurement Tutorial DC Voltage Measurement Circuit Loading ErrorMeasuring Input Bias Current Error Input Bias Current ErrorResistance Measurement Wire OhmsCorrecting for Test Lead Resistance in 2-Wire Ohms Full Scale Voltage Test CurrentTesting Electrolytic Capacitors Testing DiodesApplications of the Ohms Functions Precision Current Source DC Current MeasurementReducing Thermal Voltages Burden Voltage Error CalculationTrue RMS Measurement AC Voltage and Current MeasurementWaveform Comparison AC Voltage and Current Measurement AC-Coupled AC Measurements Crest FactorCombined AC and DC Measurements Zero-Input VAC ErrorBandwidth 20Ω Ranges Reduction of Zero-Input Error10. Shielding for Low Voltage Measurements Making Accurate HIGH-RESISTANCE Measurements12. Leakage Resistance in High Resistance Measurement Theory of Operation True RMS AC Option VAC Scaling MA AC Scaling Overall Functional Description DC Scaling Detailed Circuit DescriptionDC Scaling DC Scaling VDC and mA DC VDC ScalingMA DC Scaling VDC ProtectionAnalog Filter Track/Hold Amplifier TRACK/HOLD CircuitTRACK/HOLD Circuit Timing Diagram for One A/D Cycle Track ConfigurationPrecision Voltage Reference Settling ConfigurationHold Configuration Pre-Charge ConfigurationOhms Current Source Ohms Current SourceOhms Functions Ohms ProtectionOhms Scaling 20. A/D Converter Analog-to-Digital Converter Precision DAC Timing/Data ControlDisplay Bootstrap Supplies23. A/D Amplifier Digital Controller Keyboard13. Digital Controller Block Diagram In-Guard Microcomputer 14. Read/Write Timing Diagrams for Internal Bus Calibration Correction Slow Medium Fast Power Line FrequencyFunction and Range Control 30. A/D Control and ComputationGuard-Crossing Communication Troubleshooting ModesGuard Crossing Keyboard/Display ControlPower Supply Bus Interface Circuitry IEEE-488 Interface OptionOut-Guard Microcomputer Guard CrossingIEEE-488 Interface Power Supply Signal ConditioningVAC Scaling Frequency Response Trimming MA AC ScalingTrue RMS AC-to-DC Conversion Static awareness Dow Chemical Maintenance External Trigger Polarity Selection Option -05 Only Instrument Type Minimum Specifications Recommended ModelFrequency Range Minimum Required Accuracy All Ranges Performance TestDC Voltage Test Slow Medium Fast MIN MAX Step Range InputVoltage Frequency AC Voltage Test Option -09 OnlyNew Offset must be stored for each new range selected Resistance TestFast MIN MAX DC Current TestDisplayed Reading Slow Medium MIN MAXInput Current Frequency CalibrationAC Current Test Option -09 Only Step Number RangeInitial Procedure Basic Calibration ProcedureCalibration Functions 12. A/D CalibrationStep Displayed Prompt L O W a B L E ErrorStep Input Step Offset and Gain CalibrationDisplayed Prompt VDC VAC1 HIGH-FREQUENCY AC Calibration Storing Variable Inputs Advanced Features and Special ConsiderationsStep Displayed PROMPT1,2 Calibrating Individual Ranges Procedure Function LOW Prompt High PromptVerifying Calibration Tolerance Check Erasing Calibration MemoryTolerance AC Calibration AT Other FrequenciesOptimizing USE of the 5450A CalibrationOptimizing Use of the 5450A Remote CalibrationCorresponding Command Front Panel FeatureComments 8842A Timing Considerations Example Calibration Program Remote ErasureExample A/D Calibration Program Disassembly ProcedureCase Removal A DisassemblyF6-062.wmf F6-063.wmf F6-064.wmf IEEE-488 Interface PCA Removal Option -05 Only True RMS AC PCA Removal Option -09 OnlyMain PCA Removal Maintenance Front Panel Disassembly Reassembly ProcedureReassembly Procedure Front Panel Disassembly Removing the Display Window Troubleshooting Internal Fuse ReplacementInitial Troubleshooting Procedure Troubleshooting 16. Overall State Table T6-162.wmf 17. Circuitry Tested by the Analog Self-Tests Diagnostic Self-Tests Test Number Self-Test DescriptionsTest Point Voltage Maintenance 8842A IN-GUARD Microcomputer System Digital Controller TroubleshootingIn-Guard Microcomputer Address Latch U219 Display System Calibration Memory U220Display Control U212 To-8 Strobe Decoder U213 Analog Control Signals Device REF. DES Evaluating Static Signals21. Analog Control Logic States DC Scaling Troubleshooting Evaluating Dynamic SignalsSupply Voltage PIN or DeviceOhms Current Source Troubleshooting Track/Hold Troubleshooting13. Typical Output Waveforms for Track/Hold Circuit TP103 Precision Voltage Reference Troubleshooting 14. Output of A/D Amplifier TP101 66. A/D Converter Troubleshooting15. Waveforms at U101-24 and U101-25 For fire protection, use exact fuse replacement only Power Supply Troubleshooting17. Waveforms at TP102 for Several Inputs on 2V DV Range Minimum Maximum Test PointService Position IEEE-488 Interface Troubleshooting OptionDiagnostic Program Switches Configuration TroubleshootingPort BIT True RMS AC Troubleshooting OptionDefective Ranges Major ProblemsDefective Stage Voltage AT TP801 Input VoltageVoltage AT TP802 More Obscure Problems Guard Crossing Troubleshooting Internal CleaningCleaning Printed Circuit Assemblies 21. Guard Crossing Test Waveforms Cleaning After Soldering8842A List of Replaceable Parts 8842A Manual Status Information HOW to Obtain PartsNewer Instruments Service CentersREF of Option no Assembly Fluke Part noRevision Level F7-011.wmf F7-012.wmf F7-013.wmf F7-014.wmf A1 Main PCA CABLE, Display HEADER,1 ROW,.156CTR,6 PIN 8842A F7-03.wmf A2 Display PCA F7-03.wmf Supply Codes for Manufacturers Supply2.wmf Service Centers Service2.wmf 8842A Options and Accessories 8842A Description ModelNumber Option Accessories Current Probes Y8100, Y8101, 80i-400 Current Shunt 80J-10High Voltage Probes 80K-6 and 80K-40 8842A Option -05 IEEE-488 Interface 805-2 External Controls Programming Instructions MaintenanceList of Replaceable Parts List of Replaceable Parts 805-6 805-7 805-8 Option -09 True RMS AC 809-2 Option -09 True RMS AC Operating Instructions 809-5 Option -09 True RMS AC PCA 809-7 809-8 Schematic Diagrams 8842A Schematic Diagrams F9-012.wmf Main PCA, A/D Converter F9-022.wmf Main PCA, Ohms Current Source F9-032.wmf Main PCA, Digital F9-042.wmf Main PCA, Power Supply F9-052.wmf Display PCA F9-062.wmf F9-071.wmf F9-072.wmf IEEE-488 Interface PCA, Option IEEE-488 Interface PCA, Option -08