Agilent Technologies AGILENT MODELS 6023A and 6028A service manual Constant Current CC Tests

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Constant Current (CC) Tests

CCSetup. Constant-current tests are analogous to constant-voltage tests, with the unit's output short circuited and the voltage set to full output to assure CC operation. Follow the general setup instructions.

Load Effect (Load Regulation). Constant current load effect is the change in dc output current (Io) resulting from a load-resistance change from short-circuit to full-load, or full-load to short-circuit. Full-load is the resistance which develops the maximum rated output voltage at current Io. Proceed as follows:

a.Connect the test equipment as shown in Figure 2-3. Operate the load in constant resistance mode (Amps/Volt) and set resistance to minimum.

b.Turn the unit's power on, and turn up voltage setting to full output.

c.Turn up output current to:

10.0Adc (0.010Vdc across Rm) (6023A). Check that the AMPS display reads about 10 amps. 3.3Adc (0.335Vdc across Rm) (6028A) Check that the AMPS display reads about 3.3 amps.

d.Increase the load resistance until the output voltage at +S and -S increases to: 20Vdc (6023A).

60Vdc (6028A).

Check that the CC LED is lighted and AMPS display still reads ≈ current setting.

e.Record voltage across Rm.

f.Short circuit the load.

g.When the reading settles (≈ 10s), record the voltage across Rm again. Check that the two recorded readings differ no more than:

±0.010mVdc (6023A)

±0.0053mVdc (6028A)

h.Disconnect the short across the load.

Source Effect (Line Regulation). Constant current source effect is the change in dc output current resulting from a change in ac input voltage from the minimum to the maximum values listed in the Specifications Table in the Operating Manual. Proceed as follows:

a.Connect the test equipment as shown in Figure 2-3. Operate the load in constant resistance mode (Amps/Volt) and set resistance to minimum.

b.Connect the unit to the ac power line through a variable autotransformer set for low line voltage (e.g. 104Vac for 120Vac).

c.Switch the unit's power on and turn up output voltage setting to full output.

d.Turn up output current to:

29.0Adc (0.029Vdc across Rm) (6023A) 10.0Adc (1.0Vdc across Rm) (6028A)

Check that the AMPS display reads ≈ current setting.

e.Increase the load resistance until the output voltage between + S and - S increases to: 7.0Vdc (603A)

20.0Vdc (6028A)

Check that the CC LED is still on and the AMPS display still reads ≈ current setting.

f.Record the voltage across Rm.

g.Adjust autotransformer to the maximum for your line voltage.

h.When the reading settles record the voltage across Rm again. Check that the two recorded readings differ no more than:

±0.0090mVdc (6023A)

±0.030mVdc (6028A)

PARD Ripple And Noise. Periodic and random deviations (PARD) in the unit's output (ripple and noise) combine to produce a residual ac current as well as an ac voltage super-imposed on the dc output. The ac voltage is measured as constant-voltage PARD. Constant-current PARD is specified as the root-mean-square (rms) output current in a frequency range 20Hz to 20MHz with the unit in CC operation. To avoid incorrect measurements, with the unit in CC operation, caused by the impedance of the electronic load at noise frequencies, use a:

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Contents Autoranging Certification Safety Summary Printing History Safety Symbol DefinitionsTable of Contents Replaceable Parts Circuit Diagrams TroubleshootingSafety Considerations ScopeItem Description Manual RevisionsIntroduction Calibration ProcedureTest Equipment Required Operation Verification TestsTest Equipment Required Type Required Characteristics USE Recommended Model1KVA Initial SetupMON Calibration ProcedureIout VoutPerformance Tests Measurement TechniquesCR7 Constant Voltage CV Tests Current-Monitoring Resistor SetupBasic Test Setup RMS Measurement Test Setup, CV Pard Test Peak-To-Peak Measurement Test Setup, CV Pard Test KHz Noise, CV Peak-to-Peak Pard 6023A 6028ALoad Transient Recovery Waveform Constant Current CC Tests CC Pard Test Setup Initial Troubleshooting Procedures TroubleshootingPIN no Signal Name Control Board Test Connector, A2J7Vdc WAVEFORM/CONDITIONS SourceElectrostatic Protection Repair and ReplacementA2 Control Board Removal Overall Troubleshooting Procedure A4 Power Mesh Board RemovalA3 Front-Panel Board Removal A1 Main Board RemovalSetup Using the TablesNode MeasurementMain Troubleshooting Setup Main Troubleshooting SetupModified Mains Cord Set For Troubleshooting Front-Panel Troubleshooting Troubleshooting No-Output FailuresPWM-ON PWM-OFF Defective Check Functional Circuits A2J7-26 A2J7-25Board Symptoms Defective Circuit Check Components Troubleshooting Bias SuppliesSymptoms Defective Check Functional Circuits Board Node + Measurement SourceNode + Measurement SourceNode + N0DE Troubleshooting AC-Turn-on Circuits Power Section BlocksSetup Measurement Source Setup MeasurementTroubleshooting PWM & Clock Relay EnablePower Limit + OUT Troubleshooting DC-To-DC ConverterPWM-ON PWM-OFFTroubleshooting CC Circuit Troubleshooting CV CircuitTroubleshooting Down Programmer Troubleshooting OVP CircuitA4U4OUT Waveforms SET Voltage Vdc Node + Page Block Diagram Overview Autoranging PowerBlock Diagram Simplified Schematic Simplified Schematic Down Programmer DC-to-DC ConverterConstant-Voltage CV Circuit Pfet Control Signals Timing DiagramConstant-Current CC Circuit Power-Limit ComparatorOvervoltage Protection OVP Circuit Control-Voltage ComparatorPulse-Width Modulator PWM Initial-Ramp CircuitBias Voltage Detector AC-Surge Dropout DetectorDisplay Circuits Second-Delay CircuitPage Reference Designators Replaceable PartsDescription Abbreviations Ordering InformationCR1 Electrical PartsCR2 CR3XA2P1 XA2P2Mechanical Parts Control Board Assembly CR3 Page Page Page VR3 VR4VR5 CR5 DS1DS5 IC A/D Cmos 3-1/2 DGT VR1VR2 Pfet NPN SIChassis Electrical TS1A2 Board Mechanical Parts A1TB1A3 Board Mechanical Parts A4 Board Mechanical PartsOption 240 240V Operation Option 220 220V OperationComponent Location and Circuit Diagrams Schematic Diagram Notes Pin locations for other semi-conductors are shown below Top View, Top Covers Removed Main Board A1 Component Location Control Board A2 Component Location Front-Panel Board A3 Component Location Power Mesh Board A4 Component Location Page Page Specifications General InformationOption 002 Hardware Input Compliance Voltage ± Current Programming Enable Table A-1. Specifications, Option Remote ProgrammingOutput Impedance 10.2 k ohm ± 5% Temperature Coefficient Status IndicatorsPower-on Preset Remote Trip and Remote Reset TimingMaximum Output Voltage logic high + On State logic lowBias Supplies DC Output Ratings 25C ± Table A-1. Specifications, Option Pulse TimingShort Circuit Output Current Pard TypicalConnector Assembly Procedure InstallationOperation Figure A-1. Mating Connector AssemblyLocal/Remote Programming Resistance Voltage or Current Figure A-4. Calculating Value of Series Dropping Resistor Remote Resistance ProgrammingFigure A-5. Remote Resistance Programming Remote Monitoring Remote Control Status IndicatorsOvervoltage Remote ResetFigure A-8. Remote Control Power-On PresetMultiple Supply System Shutdown AC Dropout Buffer CircuitBias Supplies MaintenanceTroubleshooting Current Programming Troubleshooting Resistance and Voltage ProgrammingFigure A-11. Troubleshooting Current Programming of CV Mode Figure A-13. Troubleshooting Status Indicators Page REF. Desig Model no Description Table A-3. Replacement Parts100 101 VR9OLD Symbol NEW Symbol Indicator and Qualifier SymbolsLogic Symbols and Definitions 102 DefinitionsSchematic Diagram Notes 103 Schematic NotesFigure A-15. Option 002 Board, Component Location 104 Schematic NotesFigure A-16. Option 002 Board, Schematic Diagram 105 Page Model 6023A Model 6028A107 108 From
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