Fluke 187 user manual Input Alert Feature, Measuring Current

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Making Measurements

Measuring Current 3

3.If you are using the A terminal, set the rotary switch to mA/A. If you are using the mA/∝ A terminal, set the rotary switch to ∝ A for currents below 5000 ∝ A

(5 mA), or mA/A for currents above 5000 ∝ A.

4.Open the circuit path to be tested. Touch the red probe to the more positive side of the break; touch the black probe to the more negative side of the break. Reversing the leads will produce a negative reading, but will not damage the meter.

5.Turn on power to the circuit; then read the display. Be

sure to note the unit given at the right side of the display (∝ A, mA, or A).

6.Turn off power to the circuit and discharge all high- voltage capacitors. Remove the meter and restore the circuit to normal operation.

Input Alert™ Feature

If a test lead is plugged into the mA/∝ A or A terminal, but the rotary switch is not correctly set to one of the current measuring positions, the beeper warns you by making a chirping sound and the display shows "LEAd5".

This Input Alert warning is intended to stop you from attempting to measure voltage, continuity, resistance, capacitance, or diode values when the leads are plugged into a current terminal.

Placing the probes across (in parallel with) a powered circuit when a lead is plugged into a current terminal can damage the circuit you are testing and blow the meter’s fuse. This can happen because the resistance through the meter’s current terminals is very low, so the meter acts like a short circuit.

Note

The beeper may sound in the presence of high electical noise, such as that found near Pulse Width Modulation (PWM) motor drives.

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Contents Model 187 Lifetime Limited Warranty Table of Contents Model 187 Making MeasurementsIii Maintenance SpecificationsList of Tables List of Figures Viii Before You Start Safety InformationContacting Fluke Safety Information WWarningBefore You Start Symbols International Electrical SymbolsIntroduction Getting AcquaintedTurning the Meter On Battery Considerations Automatic Power OffLow Battery Indication Automatic Backlight OffRotary Switch Rotary SwitchPushbuttons PushbuttonsRotary Switch Selections Position Rotary Switch Function Blue Key FunctionRotary Switch Positions View MEMButton Pushbuttons Yellow Button Description Function Pushbuttons Button Description Yellow Button FunctionUnderstanding the Display Selecting the RangePrimary Display Bar Graph Secondary DisplayDisplay Features Number Feature Display Features Description Display Features Number 8.8.8Number Feature Display Features DescriptionDisplay Features Number 51000 FMS8888 HM8888 8.8Using the Input Terminals Input TerminalsUsing Display Hold Display Hold and AutoHOLDUsing AutoHOLD Using MIN MAXModel 187 Using Fast MN MX Min Max AvgUsing Relative Mode REL Using Hold with MIN MAX or Fast MN MXMaking Measurements Measuring VoltageMeasuring AC Voltage AC Voltage MeasurementDB Measurements in AC Volts Functions DBm DisplayMeasuring DC Voltage Both AC and DC Voltage MeasurementsAC over DC DC over AC AC and DC DisplayMeasuring Resistance Capacitors before measuring resistanceOFF Testing for Continuity Automatically subtract this valueUsing Conductance for High Resistance Tests For in-circuit tests, turn circuit power off Conductance Measurement Measuring Capacitance Testing Diodes Capacitance MeasurementDiode Test Shock, do not connect the thermocouples to Measuring TemperatureElectrically live circuits Measuring Current Input RangesInput Alert Feature Measuring CurrentMeasuring AC Current Following are some tips for measuring current11. AC Current Measurement Measuring DC Current Total current to circuit Current through one componentMeasuring Frequency 13. Functions Allowing Frequency MeasurementMeasuring Duty Cycle 14. Hz DisplayMeasures Positive Pulse Measures Negative PulseMeasuring Pulse Width 16. Duty Cycle DisplayStart and Stop on Positive Slope Start and Stop on Negative Slope18. Pulse Width Display Using Memory & Communications Features Types of MemorySaved Readings Memory Logged Readings MemoryStarting Logging Storing Saved ReadingsStopping Logging Viewing Memory Data To avoid electric shock, disconnect the testView Display MEMUsing Communications 187 Clearing MemoryChanging the Default Settings Selecting Setup OptionsFunction Specific Setup Selections Factory DefaultPrecondition OptionCommon Setup Selections ChoicesAdjusting the Temperature Offset Changing the Default Settings Selecting Display Resolution 3 1/2 or 4 1/2 Digits Setting the Power Off TimeoutSetting the 24-Hour Clock Setting the Line Main FrequencyReturning to Factory Defaults Saving Setup OptionsIntroduction General Maintenance MaintenanceTesting the Fuses Replace F2 if Replace F1 if Displayed Replacing the Batteries Battery and Fuse Replacement User-Replaceable Parts Replacing the FusesCase of Difficulty MP8 MP9 Specifications Safety and CompliancesPhysical Specifications Feature Summary Basic Specifications Detailed Accuracy Specifications Accuracy Function 45-1 kHz20 kHz KHz-100 kHzDC a 500.00 Ω Capacitance Diode Test MIN MAX AVG Frequency Counter Sensitivity Burden Voltage A, mA, µAInput Characteristics