FLUKE45是具有五位数字显示的四位半数字式多用表。可用于测量直流电压、交流电压、直流电流、交流电流、电阻、频率、两个端点之间的通断及二极管测试。测量范围可手动选择，也可自动选择。可测量输入量的绝对数值，也可测量输入量之间的相对值。可选择21种参考阻抗做功率测量，阻抗由2Ω到8000Ω，测量结果显示为dBm值(毫瓦分贝值，dBm=10log10 (1000×value2/reference impedance，其中value为测量到的rms电压值，单位为V)。利用其“保持”功能还可测量输入的最大值、最小值。可同时测量两个量，例如：交流电压的电压值及其频率；输入电压中交流分量的rms电压值和直流分量电压值；等等。有三种测量速度供选择：慢、中等、快。相对地，测量速度慢，则测量精度高；测量速度快，则测量精度低。上述功能是通过人在仪器的正面面板上操作来实现的，称其为手工操作使用。在仪器的背面面板上还有RS-232接口和GPIB/IEEE-488接口。将这些接口与PC机相连，可选用Quick Start 45 软件包，实现FLUKE 45 与PC机之间的快速设置和通讯，可方便地编制、存储和调用使用者自定义的测量程序。从而实现对该仪器的遥控使用。
FLUKE45可选择交流供电和直流电池供电。所以，它既可以在实验室使用，也可以在室外使用。直流供电电压为8V。
要真正使用好一台仪器，必须阅读该仪器的说明书，并在使用过程中反复查阅。与过去的多用表相比，FLUK45是一个较复杂的仪器。特别是对该仪器的遥控使用，它要求使用者具有关于计算机方面的知识。由于本实验教材篇幅有限，这里只对手工操作使用做简介。
了解该仪器的性能指标对于正确使用该仪器、以及分析测量结果的精度是十分重要的。直接阅读原版用户手册，比阅读翻译后的用户手册更有利于了解关于本仪器的具体性能指标和基本操作使用方法。所以直接从 “FLUKE45 Dual Display Multimeter, Users Manual”摘录了以下内容，其中包含该仪器的性能指标和手工操作使用该仪器的基本操作方法。建议在使用本仪器之前，使用者必须阅读以下的内容。这些内容是手工操作使用该仪器所必须知道的内容。
Specifications
The following specifications are under the assume of
●A 1-year calibration cycle
●An operating temperature of 18 to28°C
●Relative humidity not exceeding 90% (non-condensing)(70% for 1,000kΩ range and above)
Accuracy is expressed as ±percentage of reading + digits.
DISPLAY COUNTS READING RATES
| Rate | Reading per Second | Full Range Display Counts |
| Slow Medium Fast | 2.5 5 20 | 99,999 30,000 3,000 |
| *Ohms full range will typically be 98,000 counts | ||
| Rate | Reading Per Second | ||
| Internal Trigger Operation (TRIGGER 1) | Internal Trigger Operation (TRIGGER 4) | Print Mode Operation (Print set at 1) | |
| Slow Medium Fast | 2.5 4.5 4.5 | 1.5 2.4 3.8 | 2.5 5.0 13.5 |
| Slow Rate | Medium Rate | Fast Rate | ||||
| Meas. Function | Auto Range* | Single Range** | Auto Range* | Single Range** | Auto Range* | Single Range** |
| V= V～ A= A～ Ω Diode Freq.*** | 1.00 2.20 0.60 0.60 1.40 0.50 1.20 | 0.60 0.80 0.50 0.50 0/60 0.50 0.50 | 0.80 2.00 0.40 0.40 1.20 0.30 1.20 | 0.40 0.60 0.30 0.30 0.40 0.30 0.50 | 0.30 1.00 0.20 0.50 0.40 0.10 0.70 | 0.10 0.30 0.10 0.30 0.10 0.10 0.30 |
| *Time to auto-range a new measurement from the lowest to the highest range and to display the result. **Typical time to change to the next higher or lower range and display the result. ***Frequency greater than 150Hz. Refer to frequency measurement rats. | ||||||
| Range | Resolution | Accuracy | |||
| Slow | Medium | Fast | (6 Months) | (1 Year) | |
| 300mV 3V 30V 300V 1000V | 10μV 100μV 1mV 10mV 100mV | 100μV 1mV 10mV 100mV 1V | 0.02%+2 0.02%+2 0.02%+2 0.02%+2 0.02%+2 | 0.025%+2 0.025%+2 0.025%+2 0.025%+2 0.025%+2 | |
| 100mV 1000mV 10V 100V 1000V | 1μV 10μV 100μV 1mV 10mV | 0.02%+6 0.02%+6 0.02%+6 0.02%+6 0.02%+6 | 0.025%+6 0.025%+6 0.025%+6 0.025%+6 0.025%+6 | ||
10MΩ in parallel with<100pF
NOTE: In the dual display mode, when the volts AC and volts DC functions are selected, the 10MΩ DC input divider is in parallel with the 1MΩ AC divider.
Normal Mode Rejection Ratio
>80 dB at 50 or 60 Hz, slow and medium rats.
>54 dB for frequencies between 50-440 Hz, slow and medium rates.
>60 dB at 50 Hz, fast rate (Note: Fast rate has no filtering).
Maximum Allowable AC Voltage While Measuring DC Voltage or (AC+DC) Voltage
| Range | Max Allowable Peak AC Voltage | Peak Normal Mode Signal | ||
| NMRR*>80dB** | NMRR>60dB** | |||
| 300mV 3V 30V 300V 1000V | 100mV 1000mV 10V 100V 1000V | 15V 15V 1000V 1000V 1000V | 15V 15V 50V 50V 200V | 15V 15V 300V 300V 1000V |
| *NMRR is Normal Mode Rejection Ratio. **Normal Mode Rejection Ratio at 50 or 60 Hz±0.1%. | ||||
>90 dB at DC, 50 or 60 Hz, (1kΩ Unbalanced, medium and slow rates).
Maximum Input
1000V DC or peak Ac on any range.
TRUE RMS AC VOLTAGE, AC-COUPLED
| Range | Resolution | ||
| Slow | Medium | Fast | |
| 300mV 3V 30V 300V 750V 100mV 1000mV 10V 100V 1000V | 1μV 10μV 100μV 1mV 10mV | 10μV 100μV 1mV 10mV 100mV | 100μV 1mV 10mV 100mV 1V |
| Frequency | Linear Accuracy | DB Accuracy | Power* | Max Input at Upper Freq | |||
| Slow | Medium | Fast | Slow/ Med. | Fast | |||
| 20-50Hz 50-10kHz 10-20kHz 20-50kHz 50-100kHz | 1%+100 0.2%+100 0.5%+100 2%+200 5%+500 | 1%+10 0.2%+10 0.5%+10 2%+20 5%+50 | 7%+2 0.5%+2 0.5%+2 2%+3 5%+6 | 0.15 0.08 0.11 0.29 0.70 | 0.72 0.17 0.17 0.34 0.78 | 2%+10 0.4%+10 1%+10 4%+20 10%+50 | 750V 750V 750V 400V 200V |
| *Error in power mode will not exceed twice the linear accuracy specification. | |||||||
Slow Reading Rat: Between 15,000 and 99,999 counts (full range).
Medium Reading Rate: Between 1,500 and 30,000 counts (full range).
Fast Reading Rate: Between 150 and 3,000 counts (full range).
Decibel Resolution
| Resolution | |
| Slow & Medium | Fast |
| 0.01dB | 0.1dB |
8000Ω 300Ω 93Ω
1200Ω 250Ω 75Ω
1000Ω 150Ω 50Ω
900Ω 135Ω 16Ω**
800Ω 125Ω 8Ω**
600Ω* 124Ω 4Ω**
| 500Ω 110Ω 2Ω** |
| *Default resistance **Reading displayed in Watts (power). |
1MΩ in parallel with<100pF.
Maximum Crest Factor
3.0
Common Mode Rejection Ratio
>60dB at 50 or 60 Hz (1kΩ unbalanced medium rate).
Maximum Input
750V rms, 1000V peak
2×107 Volt-Hertz product on any range, normal mode input.
1×106 Volt-Hertz product on any range, normal mode input.
(AC+DC) Voltage Accuracy
Total Measurement Error will not exceed the sum of the separate AC and DC accuracy specifications, plus 1 display count. Refer to table under “Maximum Allowable AC Voltage while Measuring DC Voltage or (AC+DC) Voltages”.
NOTE: When measuring AC+DC, (or any dual display combination of AC and DC) in the fast reading rate, the Fluke 45 may show significant errors. This results from a lack of filtering on the DC portion of the measurement for the fast reading rate. To avoid this problem, use only the “slow” and “medium” reading rates for AC+DC or AC and DC combination.
Maximum Frequency of AC Voltage Input While Measuring AC Current
When the meter makes AC current and AC voltage measurements using the dual display, the maximum frequency of the voltage input is limited to the maximum frequency of the current function. For example, if you are making an AC current measurement on the 10A range, the maximum frequency of the voltage input must be less than 2kHz.
DC CURRENT
| Range | Resolution | Accuracy | Burden Voltage* | ||
| Slow | Medium | Fast | |||
| 30mA 100mA 10A 10mA 100mA 10A | 100nA 1μA 100μA | 1μA 10μA 1mA | 10μA 100μA 10mA | 0.05%+3 0.05+2 0.2+5 0.05%+15 0.05%+5 0.2%+7 | 0.45V 1.4V 0.25V 0.14V 1.4V 0.25V |
| *Typical at full range. | |||||
To be used in protected, low energy circuits only, not to exceed 250V or 4800 Volt-Amps (IEC 6 Installation Category II.)
mA : 300mA DC or AC rms. Protected with a 500mA, 250V,IEC 127-sheet I, fast blow fuse.
A: 10A Dc or AC rms continuous, or 20A DC or AC rms for 30 second maximum. Protected with a 15A, 250V, 10,000A interrupt rating, fast blow fuse.
NOTE: Resistance between the COM binding post and the meter’s internal measuring circuit is approximately .003Ω.
AC CURRENT
| Range | Resolution | Burden Voltage* | ||
| Slow | Medium | Fast | ||
| 10mA 30mA 100mA 10A | 100nA 1μA 100μA | 1μA 10μA 1mA | 10μA 100μA 10mA | 0.14V 0.45V 1.4V 0.25V |
| *Typical at full range. | ||||
| Range | Frequency | Accuracy | ||
| Slow | Medium | Fast | ||
| mA (To 100mA) mA (To 100mA) mA (To 100mA) A (1-10A) A (1-10A) A (0.5 to 1A) A (0.5 to 1A) | 20-50Hz 50Hz-10kHz 10-20kHz 20-50kHz 50Hz-2kHz 20-50Hz 50Hz-2kHz | 2%+100 0.5%+100 2%+200 2%+100 1%+100 2%+300 1%+300 | 2%+10 0.5%+10 2%+20 2%+10 1%+10 2%+30 1%+30 | 7%+2 0.8%+2 2%+3 7%+2 1.3%+2 7%+4 1.3%+4 |
Slow Reading Rat: Between 15,000 and 99,999 counts (full range).
Medium Reading Rate: Between 1,500 and 30,000 counts (full range).
Fast Reading Rate: Between 150 and 3,000 counts (full range).
Maximum Crest Factor
3.0
Maximum Input
To be used in protected, low energy circuits only, not to exceed 250V or 4800 Volt-Amps (IEC 6 Installation Category II.)
mA : 300mA DC or AC rms. Protected with a 500mA, 250V,IEC 127-sheet I, fast blow fuse.
A: 10A Dc or AC rms continuous, or 20A DC or AC rms for 30 second maximum. Protected with a 15A, 250V, 10,000A interrupt rating, fast blow fuse.
NOTE: Resistance between the COM binding post and the meter’s internal measuring circuit is approximately .003Ω.
OHMS
| Range | Resolution | Accuracy | Typical Full Scale Voltage | Max Current Through the Unknown | ||
Slow | Medium | Fast | ||||
| 300Ω 3kΩ 39kΩ 300kΩ 3MΩ 30MΩ 300MΩ* 100Ω 1000Ω 10kΩ 100kΩ 1000kΩ 10MΩ 100MΩ* | 1mΩ 10mΩ 100mΩ 1Ω 10Ω 100Ω 100kΩ | 10mΩ 100mΩ 1Ω 10Ω 100Ω 1000Ω 100kΩ | 100mΩ 1Ω 10Ω 100Ω 1kΩ 10kΩ 1MΩ | 0.05%+2+0.02Ω 0.05%+2 0.05%+2 0.05%+2 0.06%+2 0.25%+2 2% 0.05%+8+0.02Ω 0.05%+8+0.02Ω 0.05%+8 0.05%+8 0.06%+8 0.25%+6 2%+2 | 0.25 0.24 0.29 0.29 0.3 2.25 2.9 0.09 0.10 0.11 0.11 0.12 1.5 2.75 | 1mA 120μA 14μA 1.5μA 150μA 320μA 320μA 1mA 120μA 14μA 1.5μA 150μA 320μA 320μA |
| *Because of the method used to measure resistance, the 100MΩ (slow) and 300MΩ (medium and fast) range cannot measure below 3.2MΩ and 20MΩ, respectively. “UL” (underload) is shown on the display for resistance below these normal points, and the computer interface output “+1E-9”. | ||||||
3.2 volts maximum on the 100Ω, 300Ω, 30MΩ, 100MΩ, and 300MΩ range, 1.5volts maximum on all other ranges.
Input Protection
500V DC or rms AC on all ranges
DIODE TEST/CONTINUITY
| Maximum Reading | Resolution | |
| Slow Medium Fast | 999.99mV 2.5V 2.5V | 10μV 100μV 1mV |
Approximately 0.7mA when measuring a forward biased junction
Audible Tone
Continuous tone for continuity. Brief tone for normal forward biased diode or semiconductor junction.
Open Circuit Voltage
3.2 volts maximum
Continuity Capture Time
50μs maximum, 10μs typical
Input Protection
500 volts DC or rms AC
NOTE: When the meter is set to measure frequency and there is no input signal (I.e., input terminals are open), the meter may read approximately 25kHz (rather than the expected zero). This is due to internal capacitive pickup of the inverter power supply into the high-impedance, input circuitry. With source impedance of<2kΩ, this pickup will not affect the accuracy or stability of the frequency reading.
FREQUENCY
Frequency Range
5Hz to >1MHz
Applicable Functions
Volts AC and Current AC
| Range | Resolution | Accuracy | |
| Slow & medium | Fast | ||
| 1000Hz 10kHz 100kHz 1000kHz 1MHz* | 0.01Hz 0.1Hz 1Hz 10Hz 100Hz | 0.1Hz 1Hz 10Hz 100Hz 1kHz | 1.05%+2 0.05%+1 0.05%+1 0.05%+1 Not Specified |
| *Specified to 1MHz, but will measure above 1MHz. | |||
| Frequency | Level (sine Wave) |
| 5Hz-100kHz 100kHz-300kHz 300kHz-1MHz Above 1MHz | 30mV rms 100mV rms 1V rms Not Specified |
| Frequency | Input | Level |
| 5Hz-20kHz 45Hz-2kHz | 100mA 10A | >3 mA rms >3 mA rms |
QUICK REFERENCE GUIDE OF OPERATING FLUKE 45
Front Panel of FLUKE 45
Rear Panel of FLUKE 45
A GUIDE TO BASIC FRONT PANEL OPERATION
| OPERATION | HOW TO PERFORM | COMMENTS |
| Select Measu. function | Press [white] button. Annunciator indicates Selected function | If secondary display is on, pressing a function button turns secondary display off. |
| Dual Display | Select any measurement function or modifier for the primary display, press “2ND”, then press a function button to select a function for secondary display. Press any function button to turn off secondary display and select that function on primary display. | Function modifiers and manual range mode cannot be selected in secondary display. Refer to the Table 4-1 for suggested applications of dual display. Or, press “2ND” twice to turn off secondary display without affecting primary display. |
| Select Manu. or autorange Up range Down range | Press “AUTO” to toggle between manual and autorange mode. Press “UP”. Press “DOWN”. | “AUTO” display in auto mode not display in manual mode. Manual range cannot be selected in secondary display. |
| Change Measu. Rat | Press “RATE” to step through “S” (Slow, 2.5 readings/sec) “M” (Medium, 5 readings/sec) “F” (Fast, 20 readings/sec) | Rate affects resolution as follows: “S”=100,000 counts. “M”=30,000 counts. “F”=3,000 counts. Selected reading rate applies to all measurement except frequency. |
| REL modifier | Press “REL” to enter and exit relative modifier In REL, readings are relative to a “base” value shown on the display before REL selected. | In REL, the manual range mode is selected and the range is set to present range. “REL” displayed. Relative modifier can be selected only in the primary display. To change this relative base, refer to “Using the Number Editor” in Section 3. |
| MN MX Modifier | Press “MN MX” to select; press to toggle between minimum and maximum value; press and hold for 2 seconds to exit. | Minimum and maximum values read since MN MX selected are stored. MN MX can be selected only in the primary display. In MN MX, manual range is selected, and the range set to present range. “MN” or “MX” shown on display. |
| Convert to dB Set dB Reference Resistance | Press “dB” button to enter and exit the decibels modifier. Press “2ND”, then press “dB”. Press “UP” or “DOWN” to scroll to value (2 to 8000Ω). Press “AUTO” to select. | dB can selected only when a voltage function is selected on the primary display. dB To abort, press any button but “AUTO”, “UP”, or “DOWN”. |
| Select audio Power | Set dB reference resistance to 2, 4, 8, or 16 Ω. Press “dB” twice. “POWER” will be shown in secondary display. | Press “dB” or any button to exit audio power. |
| Hold display Reading [Touch Hold] | Press “HOLD” to ente Touch Hold. Press again to update reading. Press “HOLD” for 2 seconds to exit. IN Touch Hold, meter emits beep each time a new stable reading is detected. | “HOLD” shown in primary display. the meter enter Touch Hold in the selected range mode (i.e., manual or autorange). Touch Hold can be selected only in primary display. To change stable measurement threshold, press “2ND”, then press “HOLD”, press “UP” or “DOWN” to select “1” (very stable), “2” (stable), or “3” (not stable). Press “AUTO” to set threshold. Press any button but “AUTO”, “UP”, or “DOWN” to abort. |
| Power-Up Configuration | To set power-up configuration to present meter configuration, press and hold down “2ND” while pressing “AUTO”. Press and hold down “AUTO” while powering the meter up to restore factory settings (see Table 3-13 for factory settings). | Meter assumes power-up configuration each time power is cycled off and on. |
| AC+DC True rms | Press “V～” and “V=” simultaneously for voltage. Press “A～” and “A=” simultaneously for current. | |
| Compare [COMP] | Set HI-LO limit before selecting compare mode. Press “2ND”, then press “AUTO” (COMP) to select compare mode. When measurement taken, “HI”, “LO”, or “PASS” shown in secondary display. If “HI” or “LO”, meter emits HI-LO alarm. | To set HI-LO limit, refer to “Using the Compare Function” in Section3. Touch Hold is automatically activated when compare mode selected. Press down “HOLD” for 2 seconds to exit Touch Hold but remain in compare mode. |
