HP 6621A, 6623A, 6624A manual Protection Features, Operating Quadrants, Range Selection

Page 44

Operating Quadrants

Figure 4-2 shows the operating locus of your power supply in three quadrants. The area in quadrant 1 shows the operating locus defined by the voltage and current settings of each output. The characteristics shown for quadrant 1 incorporate remote sensing and include the maximum available sense voltage plus load lead drop. The area in quadrant 2 indicates the locus where each output can operate as a current sink. You cannot program current limit values in quadrant 2. (Figure 4-3 shows the current sink characteristics at voltages below 2.0 V in greater detail.) The area in quadrant 4 illustrates the reverse polarity diode characteristics of each output. Do not operate any output with reverse-voltage currents that are greater than the maximum rating of the output.

Notice that the L shaped characteristics in quadrant 1 of Figure l-l consists of two overlapping ranges-a high voltage/low current range, and a low voltage/high current range. The power supply always limits its settings to within the boundaries of these ranges. Attempting to program voltage or current values that are greater than the maximum programmable values for a given output results in an error message and the values are ignored by the supply.

Range Selection

When a voltage and current are specified, each of which is within the maximum programmable value but whose combination lies outside the L shaped operating locus, the power supply will automatically select the operating range based on the value of the last VSET or ISET parameter that was programmed. The other parameter will automatically be reprogrammed to the maximum rating of the selected range. Chapter 5 includes an example of automatic range selection (also referred to as range switching).

Once your power supply output is operating in a given range, it will not automatically switch to the other range because of a change in the load. The only time an output switches operating ranges is in response to a command from either the front panel or the HP-IB that changes the voltage or current settings. For the output to switch ranges, the voltage or current setting must specify a value that is inside the operating locus of the other range. If the value sent is common to both ranges, no range switching occurs.

Protection Features

Protective circuitry within the supply can limit or turn off an output in the event of an abnormal condition. The activated protection feature can be determined by observing the front panel display area. You can also read back the status of the supply over the HP-IB. The following protection features are implemented:

OVERVOLTAGE -- shorts the output by firing an SCR crowbar and sets zero volts and minimum current on an output if any of the following conditions are present:

1.The output voltage exceeds the programmed overvoltage trip point. or

2.The voltage from the +V output terminal to the + S terminal or from the -S terminal to the -V output terminal exceeds

1.5V (applies to remote sensing only).

or

3. A trip signal is received on the output's OV terminals.

or

4. The output's fixed overvoltage circuit is activated.

The OV trip point can be programmed up to 23 V on a low voltage output and up to 55 V on a high voltage output. When an overvoltage occurs, the word OVERVOLTAGE appears in the front panel display and the OV status bit is set for that output. Chapter 5 explains how to program the overvoltage trip level.

44 Output Connections and Operating Information

Page 43 Page 45
Image 44
Page 43 Page 45
Contents Operating Manual HP Part NoCertification Safety Summary Safety Summary Symbol DescriptionDeclaration of Conformity EMCInstallation Procedures Appendix A--Calibration ProcedureAppendix C--Command Summary Appendix D--Error MessagesTable Of Contents Remote Operation Local OperationCommand Summary Error MessagesCalibration Programming With The Series 200/300 ComputerPage Safety Considerations General InformationIntroduction Instrument and Manual IdentificationOutput Combinations Available Model AccessoriesDescription HP-IB Board Basic OperationOutput Low Range Values High Range Values Output Boards Definitions SpecificationsQualifying Conditions Output Response Characteristics Specifications Source EffectSupplemental Characteristics Outputs Low High Voltage Temperature CoefficientOutputs Low High Voltage Programming Resolution Readback ResolutionAC Input Power and Current Command Processing Time see FigureSafety Agency Compliance Dimensions all modelsOutput Impedance Low Voltage High Voltage 80 W Low VoltageGeneral Information General Information General Information General Information Location and Cooling InstallationInitial Inspection Input Power Requirements Line FuseLine Fuses 100/120 2110-0342 220/240 2110-0055Power Cord Line Voltage ConversionHP-IB Interface Connector Page Turning On Your Supply Front Panel Controls and IndicatorsGetting Started LCL key HP-IB Status AnnunciatorsPower Supply Status AnnunciatorsAlphanumeric LCD System Control KeysOutput Control Keys Normal Self Test Indications Line SwitchNumeric Entry Keys Checking Out Your Supply Using Local Control Sample Self-Test Failure DisplayCurrent Test Voltage TestOvervoltage Test Introduction To Remote Operation Iset EnterOCP Enter/Output StatementsSending a Remote Command OutputReading the HP-IB Address AddrDisp a Often Used CommandsGetting Data From The Supply Disp a Returning the Supply to Local Mode Output Connections and Operating Information Output RangesRange Selection Protection FeaturesOperating Quadrants Typical Output Range Characteristics Connecting the Load Page Cross Section Meters Area in mm2 Wire Bundled 10 a 20 aFeet Positive and Negative Voltages Remote Voltage SensingMultiple Loads Remote Voltage Sensing Remote Sense ConnectionsOutput Type Formula Output Noise ConsiderationsProgramming Response Time with an Output Capacitor Open Sense LeadsOvervoltage Trigger Connections External Trigger CircuitEquivalent Internal OV Trigger Circuit Parallel Operation Power Supply Protection ConsiderationsBattery Charging Maximum Allowable Voltage Setting CV OperationCC Operation Remote SensingSeries Operation 13. Series Connections with Local Sensing CV OperationSpecifications for Series Operation 14. Series Connections with Remote SensingPage Page Interface Function Remote OperationHP-IB Operation HP-IB Address Selection Numeric Data Power-On Service Request PONProgramming Syntax Sheet 1 of 2. Syntax Forms for Power Supply Commands Sheet 2 of 2. Syntax Forms for Power Supply Commands Fault ? VsetIset OvsetPage Power Supply Commands Initial ConditionsVoltage Programming Current ProgrammingRange Switching OVSET? Output On/OffOvervoltage OV Protection Overcurrent Protection OCP Multiple Output Storage & RecallClear Command Status ReportingUNR +CC ASTS?FAULT? UNMASK?Unmask 2,XXX Bit Assignment of the Serial Poll RegisterService Request Generation SRQ? PON ?Display On/Off Reprogramming DelayRQS Bit Other Queries Response Code Front PanelExplanation TEST? Responses Code ExplanationPage Local Mode Local OperationLocal Control Of Output Functions GeneralSetting Voltage Setting CurrentSetting Overvoltage Protection Resetting Overvoltage ProtectionResetting Overcurrent Protection Displaying the Contents of the Fault RegisterSetting the Reprogramming Delay Setting the Supplys HP-IB AddressLocal Control Of System Functions ConditionDisplaying Error Messages Addr EnterSTO Enter RCL EnterPage Calibration Procedures Test Equipment and Setup RequiredFigure A-1. Calibration Setup General Calibration Procedure Are not stored. Exercise care when moving the leads Calibration Program 10 ! Calibration ExampleClear Voltmeter Output Buffer PauseFnend Input ANY More Outputs to CALIBRATE? Y or N,X$Disp END of Calibration Program Page Page Voltage and Current Programming Programming With a Series 200/300 ComputerPath Names Voltage and Current Programming With Variables Voltage and Current ReadbackProgramming Power Supply Registers Print OUTPUT1 is in CV Mode END ifService Request and Serial Poll Present StatusEnable Intr OFF IntrPrint Overvoltage on Output #1 Print Overvoltage on Output #2Error Detection Programming Outputs Connected In Parallel Stored Operating StatesInput Enter Voltage LIMIT,V Input Enter Operating VOLTAGE,V1Programming Outputs Connected In Series Input Enter the Desired Current Limit POINT,ICommand Description Command SummaryTable C-1. Command Summary Table C-l. Command Summary PON? ROM?Previously Error Codes and Messages Power-On Self Test Messages Error ResponsesTable D-l. Power-On Self Test Error Message Test ResponsesTable D-2. Error Responses Error Code Message Explanation ERR? query ERR keyTable D-3. TEST? Responses Response Code Explanation TEST? queryPage Manual Backdating Make ChangesGenerally Applicable Annotations II. CE92 Product Specific Annotations6621A 6623AOr contact EuropeFar East Latin America
Top Page Image Contents