Fluke 35040 manual Using the RESET/MEASURE Button, Overranging Conditions

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Operation

Operation Instructions 3

3.9.12 Using the RESET/MEASURE Button

The RESET/MEASURE button has dual functionality. If no Measurement screen is displayed, pressing the RESET / MEASURE button displays one. When a Measurement Screen is displayed, pressing the RESET/MEASURE button zeroes all measurement readings and causes the Model 35040 Therapy Dosimeter to restart the measurement process.

Press the UP arrow to display the next Measurement screen. Press the DOWN arrow to display the previous Measurement screen. The Measurement screens are user customizable via the Customization software (see Section 3-10).

The Model 35040 Therapy Dosimeter is always collecting charge from the ion chamber, even when a Measurement screen is not displayed.

The operator may view the Detector Select screen, the Air Density screen, the Test Function screen, or the Units Select screen, make changes, and return to the Measurement screen to see the results. Changing the bias voltage, the start threshold, or the stop threshold, automatically zeros all measurement readings.

ADC 39.995 nC

659.8pA

59.891 s

Figure 3-26. The Measurement Screen

NOTE

Press RESET/MEASURE from the Measurement screen to restart the leakage measurement process after moving the triax cable connected to the Model 35040 Therapy Dosimeter.

The measurements have different visual cues to assist the operator in understanding the measurement. If the instrument is trying to acquire enough data to make a measurement, the display area will be filled with dashes. If the measurement is being actively updated, the decimal point will flash. When there was inadequate time to get enough data for leakage compensation, a question mark is displayed to the left of the measurement. If the measurement cannot be made due to the selected settings, the measurement is replaced by “NA.” If the measurement has too much variation to be reliable, “INVALID” is substituted.

3.9.13 Overranging Conditions

The Model 35040 Therapy Dosimeter displays an overrange indicator (“OVER”) when the electrometer’s maximum limit has been exceeded (see Figure 3-27).

ADC

OVER nC

OVER pA

OVER s

Figure 3-27. The Measurement Screen With the Charge and Current Limits Exceeded Within the First 60 Seconds

3-17

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Contents Therapy Dosimeter 35040Fluke Biomedical Table of Contents Sample Customization Reports Troubleshooting and ServiceAddendum Features of Firmware Version 27JAN00 or Later Iii Blank Introduction FeaturesIntroduction Operators Manual Before You Start Safety PrecautionsSafety Symbols And Terms Factory Calibration Error Source ± %rdg SpecificationsMaximum Error Manual AddendaFull Scale Range Display Resolution Full Scale Range Display Resolution Noise ± countsTimed Charge Measurements Current MeasurementsGeneral Measurements SpecificationsEffective Exposure Time Measurements High Performance Power Supply and Battery Charger Unpacking and Inspection 35040 Functional Description Hardware Block Diagram of the Model 35040 Therapy DosimeterFront Panel Power SupplyMicroController Serial Communications PortElectrometer Basic Operating EquationsBias Supply Multiplexer and A/D ConverterQExposure Quantity Description Units CommentsQAccum QAccumprevious= time of electrometer conversion s Charge and Current MeasurementsLeakage Measurements Timed Charge and Dose Exposure Charge and DosePredicted Timed Charge and Dose Setting ThresholdsAccumulated Charge and Dose Exposure Current and RateDoseRate = I a × Iccf Units/C × Adcf × RateMultiplier s Exposure TimeMm Hg = inch Hg x Air Density Correction Factor⎝ P Units Display Minimum Maximum Standard Resolution ErrorSetup SetupFront Panel Familiarization IntroductionRear Panel Familiarization Powering The SystemIon Chamber Connector Power-Up Self-Test and Display MessagesMaking Non-Timed Exposure Measurements Basic Measurement TechniquesGeneral Considerations 3Making Timed Exposure Measurements Timer SetupTimer Use Using Other Ion Chambers Battery CareBattery Care PowerOperation Instructions Front Panel ControlsPowering Up the Model 35040 Therapy Dosimeter Operation Instructions Powering Down the Model 35040 Therapy DosimeterUsing the Test Function Button QScaleFactor=1.0000 IScaleFactor=1.0000 5Automatic Leakage Compensation 12. The Test Function Screen Showing the Timer SettingsCalibrated by Keithley RMD Nov 15 17. The Test Function Screen Showing the Timer Settings 6Timer Setup Using the AIR Density Button Using the Detector Select ButtonUsing the Bias Select Button Using the Units Select ButtonSet 300.0 V 100% Central Electrde Pos IC Bias 300.0 V CEP Overranging Conditions Using the RESET/MEASURE ButtonCondition Values Overranged Reset ErrorOverrange Conditions Annunciators Reset Error With Automatic Leakage Compensation EnabledAnnunciators Annunciator ConditionIndicator Measurement Condition Measurement Indicators and Conditions? left of value Condition Overranged MeasurementCustomization Installing/Uninstalling Customization SoftwareConnection to the Computer Starting the Customization SoftwareCOM Port Drop Down List DownloadingMenu Items and Controls File Save AS and File Print Ion ChambersClose or File Close Edit Special Items OK and Cancel36. The Special Items Menu Calibration Temperature has focus Download and CancelMeasurement Displays Display Line Operators Manual Available Display LinesDisplay Line Group Selection Using the APPEND, DELETE, and Insert ButtonsSelecting an Item and Placing It Changing a Line on a Display38. The Timer Intervals Form Timer Intervals39. The Bias Settings Form Bias SettingsExamples Customizing a Measurement Display Changing the Pressure UnitsAppending a Display Deleting a DisplayErrors Troubleshooting Troubleshooting and ServiceSymptom ??Bias annunciator displayed Symptom Display does not light up when Power is pressedSymptom HiBias annunciator displayed Symptom LoBias annunciator displayedSymptom Configuration Error displayed Symptom Internal Reset Error displayedBit Description Action Do not makeSymptom Dashes displayed instead of digits Symptom Current Overrange DisplayedSymptom Bias voltage measurement changes by one digit Measurements. ReturnExample 299.9 to Display Will Not Light Hours? Is the battery voltage greater than 5.9 volts? Low BatteryLine Bias ErrorGo to Model 35040 Therapy Dosimeter Fuse Replacement Line Fuse ReplacementReplaceable Parts Information Interface Connector CleaningCleaning The Instrument Replaceable Parts List Warranty InformationRecalibration, Repair Information & Technical Assistance Replaceable Parts InformationBlank Sample Documents Sample Customization Reports35040 Appendix Sample Customization Reports 35040 Appendix Sample Customization Reports Blank Timed Measurements Introduction New FeaturesOverview Specifications Update New Features B SetupMaking Timed Exposure Measurements Timer Setup ProcedureTimer Use Procedure Setup B RESET/MEASUREAutomatic Leakage Compensation ADC ALCOperation Instructions B Start NA pA Stop Thres CurrentDecimal Places Timer SetupTable B-1. Annunciators Annunciators, Indicators, and Overrange ConditionsTable B-2. Measurement Indicators and Conditions Condition Overranged Measurement1 Table B-3. Overrange ConditionsTheory of Operation Theory Of OperationConfiguration Error Service Required Error Number Measurement Displays Main MenuMeasurement Menu Figure B-9 shows the Measurement Displays dialog box Table B-4. Available Display Lines Figure B-10. The Timer Intervals dialog box Page Fluke Biomedical