Fluke 45 Measuring Voltage, Resistance, or Frequency, Measuring Current, Diode/Continuity Testing

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45

Users Manual

Measuring Voltage, Resistance, or Frequency

To measure voltage, resistance, or frequency, press the desired function button and connect the test leads as shown in Figure 2-5. The meter will select the appropriate range in the autorange mode, and an annunciator on the display will indicate measurement units.

Note

After measuring high voltage to 1000 V dc, errors may occur when making measurements with 1 to 10 µV resolution. Allow up to two minutes prior to making low-level measurements.

Measuring Current

To measure current, insert the test leads in the 100 mA input terminal for currents up to 100 mA or in the 10 A input terminal for higher current. Press Cor Dand connect the test leads as shown in Figure 2-6 and described in the following procedure:

1.Turn off power in the circuit to be measured.

2.Break the circuit (on the ground side to minimize the common mode voltage), and place the meter in series at that point. (To measure current without breaking the circuit, use a current clamp.)

3.Turn on power to the circuit, and read the display. The meter will select the appropriate range automatically, and an annunciator on the display will indicate the units of the measurement value shown.

4.Turn off power to the circuit and disconnect the meter from the tested circuit.

Note

After measuring high current using the 10 A input, thermal voltages are generated that may create errors when making low-level (high sensitivity) dc measurements of volts, current, or ohms. To make the most accurate measurements, allow up to ten minutes for the thermals to settle out.

Diode/Continuity Testing

Diode and continuity tests are performed by a diode test function with a continuity beeper that can be turned on and off.

The continuity test determines whether a circuit is intact (i.e., has a resistance less than about 30 Ω ). The meter detects continuity for intervals as brief as 50 µs. The continuity test function cannot be selected for the secondary display.

To perform a continuity test, press G, and connect the test leads as shown in Figure 2-7. The beeper emits a single beep when the input drops below +0.8 V (approximately 1 kΩ ), and emits a continuous tone when the input goes below +25 mV (approximately 30 Ω ).

The diode test measures the forward voltage of a semiconductor junction (or junctions) at approximately 0.7 mA. Readings are displayed in the 3 V range at the medium and fast measurement rates. "OL" is displayed for voltages above +2.5 V. If the diode test is performed at the slow reading rate, readings are displayed in millivolts on the 1000 mV (1 V) range.

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Contents Dual Display Multimeter Limited Warranty & Limitation of Liability Declaration of the Manufacturer or Importer Page Table of Contents Applications Appendices Page List of Tables Page List of Figures Introducing the Fluke 45 Dual Display Multimeter IntroductionModel Accessories Description Options and AccessoriesWhere to go from Here Maintenance Appendices Page Multimeter Safety Page Getting Started IntroductionFront Panel Turning the Meter on Using the PushbuttonsSummary of Basic Pushbutton Operations Taking Some Basic Measurements Selecting a Measurement RangeAutomatic Input Terminal Selection Measuring Current Diode/Continuity TestingMeasuring Voltage, Resistance, or Frequency Freq Continuity Testing Rack Mounting Operating the Meter Under Battery Power OptionalPage Front Panel Operations Operating the Meter From the Front PanelSecondary Display DisplayPrimary Display Remote SMF Input Terminals Input TerminalsInput Limits Selecting a Measurement FunctionRanging AutorangingFunction Buttons Frequency Ranges and Full Scale Values Slow and Medium Slow Reading Rate Range Full ScaleOhms Ranges and Full Scale Values Fast Reading Rate Medium Reading Rate Range Full ScaleFrequency Ranging Measuring FrequencyManual Ranging Frequency Measurement Rates Frequency Measurement RatesMeasuring Frequency of Current 100 mA and 10A Inputs Frequency Sensitivity SelectionMaximim Input Voltage Selecting a Function ModifierMaximum Sinewave Inputs for Frequency Measurements Range Function Modifier Selection Buttons REL Relative Readings ModifierReference Impedances in Ohms DB Decibels and Audio Power ModifierMN MX Minimum Maximum Modifier Using Function Modifiers in CombinationHold Touch Hold Modifier Selecting a Measurement Rate Rate Using the SButton10. SButton Operations PushbuttonsList and Number Editors Using The Compare Comp FunctionUsing the List Editor Using the Number Editor Changing the Power-Up Configuration Power-Up ConfigurationFactory Settings of Power-Up Configuration Calibration 13. Power-Up Configuration Set at Factory ParameterConfigurations Applications Using the Dual DisplayDual Display Showing Volts AC and Frequency Using Measurement Functions in CombinationApplications Sample Dual Display Applications Primary DisplayResponse Times DC Voltage and DC Current Measurement on Input SignalHow the Meter Makes Dual Display Measurements Slow Med Fast Slow Rate Auto Single Range1 Range2 Medium Rate Fast RateExternal Trigger Update Rate in the Dual Display ModeAll Thermal VoltagesCorrecting for Test Lead Resistance When Measuring ResistanceTwo-Wire Configuration True RMS MeasurementsWaveform Comparison True RMS vs. Average-Responding Meters Effects of Internal Noise in AC MeasurementsCalculated AC + DC RMS Measurements True RMS Measurements Page Computer Interfaces Local and Remote OperationsPreparing the Meter for Operations via the RS-232 Interface Setting Communication Parameters RS-232Factory Settings of RS-232 Communication Parameters Factory SettingRS-232 Print-Only Mode RS-232 Prompts Device Clear Using C Cntrl CCabling the Meter to a Host or Printer RS-232 Character Echoing and DeletionEnabling the IEEE-488 Interface Installing the IEEE-488 InterfacePreparing the Meter to be Operated via IEEE-488 Interface IEEE-488 Operating LimitationsCabling the Meter to a Host Getting Started With An Installation TestInstallation Test for RS-232 Operations Installation Test for IEEE-488 OperationsInput Terminators How the Meter Processes InputIf Test Fails Input StringsSending Numeric Values to the Meter Sending Command Strings to the MeterTypical IEEE-488 Input Strings Page Typical IEEE-488 Input Strings External Triggering from the Front Panel How the Meter Processes OutputTriggering Output External Triggering via the Computer Interface Setting the Trigger Type ConfigurationRear Trigger Service Requests IEEE-488 Only and Status RegistersSettling Delay Trigger TypeStatus Register Summary Read CommandWrite Command Enable RegisterESB MAV 3 2 1 Event Status and Event Status Enable Registers Event Status and Event Status Enable RegistersTrue Set to 1 Conditions Status Byte RegisterReading the Status Byte Register Description of Bits in ESR and ESE Bit No NameTrue Set to 1 Condition Service Request Enable RegisterDescription of Bits in the Status Byte Register Bit No Name IEEE-488 Capabilities and Common Commands Computer Interface Command SetIEEE-488 Interface Function Subsets IEEE-488 Common CommandsNumber State 10. IEEE-488 Common Commands11. Function Commands and Queries Primary Secondary Display Function Commands and QueriesFunction Modifier Commands and Queries Value Ref Impedance Command12. Function Modifier Commands and Queries Description 12A. Reference Impedance Values Ref ImpedanceMIN Frequency Range Range and Measurement Rate Commands and QueriesOhms Range Current Range14. Measurement Queries Description 13. Range and Measurement Rate Commands and QueriesMeasurement Queries 16. Trigger Configuration Commands Description Compare Commands and QueriesTrigger Configuration Commands 15. Compare Commands and Queries DescriptionMeasurement Function Miscellaneous Commands and Queries17. Miscellaneous Commands and Queries Description 16A. Measurement Units Output with Format18. Remote/Local Configuration Commands Description RS-232 Remote/Local ConfigurationsSample Program for RS-232 Computer Interface Sample Program Using the RS-232 Computer InterfaceSample Programs for IEEE-488 Computer Interface Sample Programs Using the IEEE-488 Computer InterfaceAam25s.tif Aam26s.tif Aam27s.tif Operating the Meter Using the Computer Interface Line Fuse Introduction CleaningCurrent Input Fuses Testing Current Input FusesFront Panel Input Terminal Replacing the 100 mA Input FuseReplacing the 10 a Input Fuse Performance Tests Self-Test Diagnostics and Error CodesError No Self-Test Error Codes Meaning Min Max ServiceInput Level FrequencyUsing decades 300 Ω Short 30 kΩ Min Max 29.982 30.018 Replacement PartsReplacement Parts Performance Tests for mA Current FunctionsTM1 TM2 TM3 TM4 TM5 Appendices Page Response Times Display Counts and Reading RatesRS-232 and IEEE-488 Reading Transfer Rates Input Impedance Normal Mode Rejection RatioCommon Mode Rejection Ratio DC VoltageAccuracy Decibel ResolutionTrue RMS AC Voltage, AC-Coupled Maximum InputAC + DC Voltage Accuracy Maximum Crest Factor Common Mode Rejection RatioDecibel Reference Resistance Accuracy DC CurrentAC Current Range SlowRangeFrequency Slow Accuracy Medium Fast Maximum Crest Factor Maximum InputDiode Test/Continuity OhmsSensitivity Level of AC Current FrequencySensitivity of AC Voltage Environmental Options GeneralASCII/IEEE-488 Bus Codes Page ASCII/IEEE-488 Bus Codes B Page Implementation of Ieee Standard IEEE-488.2 Device Documentation RequirementsNumeric Response Data Measurement *RDT and *RAT? commands are not implemented
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45 specifications

The Fluke 45 is a versatile and high-precision Digital Multimeter that is designed for a wide range of applications in electrical testing, troubleshooting, and maintenance. Known for its reliability and advanced features, the Fluke 45 is an essential tool for engineers, technicians, and professionals who require accurate measurement capabilities.

One of the standout features of the Fluke 45 is its ability to measure both AC and DC voltage and current. With a maximum input voltage of 1000 volts and current ranges up to 10 amps, users can conduct a variety of electrical tests with confidence. The device is equipped with an intuitive dual display, allowing for simultaneous viewing of multiple measurements. This feature enhances usability during complex diagnostics.

The Fluke 45 also boasts an impressive resolution of 0.1 mV and a basic accuracy of 0.25%, which translates to highly reliable readings. The auto-ranging capability simplifies the measurement process, automatically selecting the appropriate range based on the input signal, thus saving time and reducing user error.

In addition to voltage and current measurements, the Fluke 45 features resistance measurement capabilities, with a range of up to 40 MΩ. This makes it an effective tool for testing circuits, identifying faults, and ensuring the integrity of electrical systems. The continuity test function, complete with a built-in beeper, assists in quickly diagnosing wiring issues.

Another remarkable characteristic of the Fluke 45 is its frequency measurement capabilities, which can measure frequencies up to 1 MHz. This is particularly useful in applications involving signal analysis and troubleshooting oscillators.

Moreover, the Fluke 45 is designed with user convenience in mind. It is lightweight and portable, making it easy to carry around, whether on a job site or in a workshop. The rugged construction, reinforced with high-quality materials, ensures it can withstand harsh conditions often encountered in the field.

To enhance functionality, the Fluke 45 features a data hold function that freezes the displayed measurement for easier reporting. Additionally, it can store data for later retrieval, making it convenient for users who need to compile test results over time.

In summary, the Fluke 45 Digital Multimeter is an advanced instrument that combines precision, versatility, and user-friendly design. Its wide measurement capabilities, high accuracy, and durable build make it an invaluable tool for professionals in diverse electrical and electronic applications. Whether for routine maintenance or complex troubleshooting, the Fluke 45 stands out as a reliable partner in achieving accurate and efficient results.
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