Fluke 120B Series Industrial ScopeMeter® Hand-Held Oscilloscopes

The Fluke ScopeMeter® 120B Series is a rugged oscilloscope for industrial electrical and electro-mechanical equipment troubleshooting and maintenance.





Simplified testing, more insight and faster electro-mechanical troubleshooting

The compact ScopeMeter® 120B Series, is the rugged oscilloscope solution for industrial electrical and electro-mechanical equipment troubleshooting and maintenance applications. It’s a truly integrated test tool, with oscilloscope, multimeter and high-speed recorder in one easy-to-use instrument. The ScopeMeter 120B Series also integrates with Fluke Connect® mobile app and FlukeView® for ScopeMeter software to enable further collaboration, data analysis and archiving of critical test information.

*Not all models are available in all countries. Check with your local Fluke representative.



The 120B Series Industrial ScopeMeter test tools include innovative functions designed to help technicians troubleshoot faster and get the answers they need to keep their systems up and running. Display waveforms with Connect-and-View™ trigger and setup technology and automatically view related numerical measurements using Fluke IntellaSet™ technology, all without making manual measurement adjustments. With Recorder Event Detect capabilities, elusive intermittent events are captured and logged for easy viewing and analysis.

  • Dual-input digital oscilloscope and multimeter
  • 40 MHz or 20 MHz oscilloscope bandwidth
  • Two 5,000-count true-rms digital multimeters
  • Connect-and-View™ trigger simplicity for hands-off operation
  • IntellaSet™ technology automatically and intelligently adjusts numerical readout based on the measured signal
  • Dual-input waveform and meter reading recorder for trending data over extended periods
  • Recorder Event Detect captures elusive intermittent signals on repetitive waveforms up to 4 kHz
  • Shielded test leads for oscilloscope, resistance and continuity measurements
  • Resistance, continuity, diode and capacitance meter measurements
  • Power measurements (W, VA, VAR, PF, DPF, Hz)
  • Voltage, current and power harmonics
  • Check Industrial networks with BusHealth physical layer tests against defined reference levels
  • Save or recall data and instrument setups
  • Store instrument setups defined by a test sequence for routine maintenance or most often used test procedures.
  • External optically isolated USB interface to transfer, archive and analyze scope or meter data
  • Optional WiFi adapter connected to internal USB port to wirelessly transfer information to the PC, laptop or Fluke Connect® mobile app*
  • FlukeView® ScopeMeter® Software for Windows®
  • Rugged design to withstand 3g Vibration, 30g shock, and rated IP51 according to EN/IEC60529
  • Highest safety rating in the industry: safety rated for CAT IV 600 V
  • Li-Ion rechargeable battery, seven-hours operation (with four-hour charge time)

*Not all models are available in all countries. Check with your local Fluke representative.


Connect-and-View™ triggering for an instant, stable display
Oscilloscope users know how difficult triggering can be. Using the wrong settings can lead to unstable waveform captures, and sometimes the wrong measurement data. Fluke’s unique Connect-and-View™ triggering technology recognizes signal patterns, and automatically sets up the correct triggering to provide a stable, reliable and repeatable display. Connect-and-View™ triggering is designed to work with virtually any signal, including motor drives and control signals – without adjusting parameters, or even touching a button. Signal changes are instantly recognized and settings are automatically adjusted, providing a stable display even when measuring multiple test points in quick succession.

The Auto Readings function with Fluke IntellaSet™ technology uses proprietary algorithms to intelligently analyze the measured waveform and automatically displays the most appropriate numerical measurements on screen, so you can get the data you need easier than ever before. As an example, when the measured waveform is a line voltage signal, the Vrms and Hz readings are automatically displayed, whereas if the measured waveform is a square wave, the Vpeak-peak and Hz readings are automatically displayed. Using IntellaSet™ technology in conjunction with Connect-and-View™ automatic triggering you can be sure you’re seeing not only the correct waveform, but the appropriate numerical reading as well. All without touching a button.


Industrial equipment needs a reliable power supply to operate properly, use the dual input to obtain key power measurements.
For single phase or 3-phase balanced systems, the dual inputs of the Industrial ScopeMeter® 120B Series can measure ac+dc rms voltage on channel A and ac+dc rms current on channel B. The Fluke 125B can then calculate; frequency, phase angle, active power (kW), reactive power (VA or var), power factor (PF) or displacement power factor (DPF) and can also calculate the power values for a 3-phase system where all phases have equal voltage and currents. This applies to both balanced system and resistive loads.

Harmonics measurements
Harmonics are periodic distortions of voltage, current, or power sine waves. Harmonics in power distribution systems are often caused by non-linear loads such as switched mode dc power supplies and adjustable speed motor drives. Harmonics can cause transformers, conductors, and motors to overheat. In the Harmonics function, the Test Tool measures harmonics to the 51st. Related data such as dc components, THD (Total Harmonic Distortion), and K factor are measured to provide a complete insight in to the electrical state of health of your loads.




Use the comprehensive recorder modes to help find intermittent faults with ease
The toughest faults to find are those that happen only once in a while – intermittent events. They can be caused by bad connections, dust, dirt, corrosion or simply broken wiring or connectors. Other factors, like line outages and sags or the starting and stopping of a motor, can also cause intermittent events resulting in equipment shutdowns. When these events happen, you may not be around to see it. But, your Fluke ScopeMeter® Test Tool will. You can either plot the minimum and maximum peak measurement values or record the waveform trace. And, with expandable micro SD memory, recording sessions can be done for up to 14 days. This recorder is even more powerful with the addition of Recorder Event Detect, which makes detecting and logging intermittent faults easier than ever. Just set a threshold on a meter reading or scope trace and deviations are tagged as unique events. You no longer need to search through masses of data to pinpoint faults, and can quickly step from one tagged event to the next, while still having access to the full data set.

Industrial BusHealth Test verifies electrical signal quality on industrial buses
BusHealth Test analyzes the electrical signals on the industrial bus or network and gives a clear “Good, “Weak or “Bad indication mark for each of the relevant parameters, presented next to the actual measurement value. Measured values are compared to standard values based on the selected bus types (CAN-bus, Profi-bus, Foundation Field, RS-232 and many more), or, unique reference values can be set if different tolerances are required. The Fluke 125B can validate the quality of the electrical signals as soon as they are passed along the network, without looking at the data content. Additionally, the 125B checks the signal levels and speed, transition times and distortion, and compares these to the appropriate standards to help you find errors such as improper cable connections, bad contacts, incorrect grounding or improper terminators.

One test lead to measure multiple electrical parameters
High frequency waveform, meter, capacitance and resistance measurements as well as continuity checks are all covered by single set of shielded test leads. No time is wasted finding or swapping leads.





FlukeView® ScopeMeter® Software for Windows®
Get more out of your ScopeMeter 120B with FlukeView® Software:

  • Store instrument’s screen copies on the PC, in color
  • Copy screen images into your reports and documentation
  • Capture and store waveform data from your ScopeMeter test tool on your PC
  • Create and archive waveform references for easy comparison
  • Copy waveform data into your spreadsheet for detailed analysis
  • Use cursors for parameter measurement
  • Add user text to instrument setups and send them to the instrument for operator reference and instructions

Note : Some functionality may be available with specific ScopeMeter test tool models only

Fluke Connect mobile app compatibility
Automated industrial machinery is harder than ever to trouble shoot. It’s not enough to just know where you have to test, you also have to know what to look for – and that can be hard without baseline measurement data or access to subject matter experts. The Fluke Connect® Assets wireless system of software and wireless test tools enables technicians to reduce maintenance costs and increase uptime with accurate equipment records and maintenance data that is easy to interpret, and share. Compare and contrast test point measurement data and trends so you can better understand signal characteristics and changes over time. And, by storing maintenance data on the Fluke Cloud™ you can enable team members to access it from wherever and whenever they need to so you can get advice or approvals in the field and get your systems up and running faster than ever before.

Product Comparison Chart Fluke 123B Fluke 124B Fluke 125B
Full Function Dual Input Scope and Meter
Oscilloscope Bandwidth MHz 20 40 40
Meter and Scope Recorder
Scope Cursor Measurements
Power and Harmonics Measurements
Included Accessories
10:1 voltage probe
i400S AC current clamp
*Not all models are available in all countries. Check with your local Fluke representative.


Oscilloscope mode
Frequency response – dc coupled Without probes and test leads (with BB120) 123B: dc to 20 MHz (-3 dB)
124B and 125B: dc to 40 MHz (-3 dB)
With STL120-IV 1:1 shielded test leads DC to 12.5 MHz (-3 dB) / dc to 20 MHz (-6 dB)
With VP41 10:1 Probe 123B: dc to 20MHz (-3 dB)
124B and 125B: dc to 40 MHz (-3 dB)
Frequency response – ac coupled (lf roll off) Without probes and test leads <10 Hz (-3 dB)
With STL120-IV 1:1 shielded test leads <10 Hz (-3 dB)
With VP41 10:1 Probe <10 Hz (-3 dB)
Rise time, excluding probes,
test leads
123B <17.5 ns
124B and 125B <8.75 ns
Input impedance Without probes and test leads 1 MΩ//20 pF
With BB120 1 MΩ//24 pF
With STL120-IV 1:1 shielded test leads 1 MΩ//230 pF
With VP41 10:1 Probe 5 MΩ//15.5 pF
Sensitivity 5 mV to 200 V/div
Analog bandwidth limiter 10 kHz
Display modes A, -A, B, -B
Max. input voltage A and B Direct, with test leads, or with VP41 Probe 600 Vrms Cat IV, 750 Vrms maximum voltage.
With BB120 600 Vrms
Max. floating voltage, from any terminal to ground 600 Vrms Cat IV, 750 Vrms up to 400Hz
Scope modes Normal, Single, Roll
Ranges (normal) Equivalent sampling 123B: 20 ns to 500 ns/div,
124B and 125B: 10 ns to 500 ns/div
Real time sampling 1 μs to 5 s/div
Single (real time) 1 μs to 5 s/div
Roll (real time) 1s to 60 s/div
Sampling rate (for both channels simultaneously) Equivalent sampling (repetitive signals) Up to 4 GS/s
Real time sampling 1 μs to 60 s/div 40 MS/s


Screen update Free run, on trigger
Source A, B
Sensitivity A and B @ DC to 5 MHz 0.5 divisions or 5 mV
@ 40 MHz 123B: 4 divisions
124B and 125B: 1.5 divisions
@ 60 MHz 123B: N/A
124B and 125B: 4 divisions
Slope Positive, negative


Advanced scope functions
Display modes Normal Captures up to 25 ns glitches and displays analog-like persistence waveform
Smooth Suppresses noise from a waveform
Glitch off Does not capture glitches between samples
Envelope Records and displays the minimum and maximum of waveforms over time
Auto set (Connect-and-View™) Continuous fully automatic adjustments of amplitude, time base, trigger levels, trigger gap, and hold-off. Manual override by user adjustment of amplitude, time base, or trigger level.


Dual input meter
The accuracy of all measurements is within ±(% of reading + number of counts) from 18 °C to 28 °C.
Add 0.1x (specific accuracy) for each °C below 18 °C or above 28 °C. For voltage measurements with 10:1 probe, add probe  uncertainty +1%. More than one waveform period must be visible on the screen.


Input A and input B
DC voltage (VDC)
Ranges 500 mV, 5 V, 50 V, 500 V, 750 V
Accuracy ±(0.5% +5 counts)
Common mode rejection (CMRR) >100 dB @ dc, >60 dB @ 50, 60, or 400 Hz
Full scale reading 5000 counts
True-rms voltages (V ac and V ac+dc)
Ranges 500 mV, 5 V, 50 V, 500 V, 750 V
Accuracy for 5% to 100% of range (DC coupled) DC to 60 Hz (V ac+dc) ±(1% +10 counts)
1 Hz to 60 Hz (V ac) ±(1% +10 counts)
Accuracy for 5% to 100% of range (AC or dc coupled) 60 Hz to 20 kHz ±(2.5% +15 counts)
DC rejection (only VAC) >50 dB
Common mode rejection (CMRR) >100 dB @ dc
>60 dB @ 50, 60, or 400 Hz
Full scale reading 5000 counts, reading is independent of any signal crest factor.
Modes Max peak, Min peak, or pk-to-pk
Ranges 500 mV, 5 V, 50 V, 500 V, 2200 V
Accuracy Accuracy Max peak or Min peak 5% of full scale
Accuracy Peak-to-Peak 10% of full scale
Full scale reading 500 counts
Frequency (Hz)
Ranges 123B: 1 Hz, 10 Hz, 100 Hz, 1 kHz, 10 kHz, 100 kHz,1 MHz, 10 MHz, and 50 MHz
124B and 125B: 1 Hz, 10 Hz, 100 Hz, 1 kHz, 10 kHz, 100 kHz, 1 MHz, 10 MHz, and 70 MHz
Frequency range 15 Hz (1 Hz) to 50 MHz in continuous autoset
Accuracy @1 Hz to 1 MHz ±(0.5% +2 counts)
Full scale reading 10,000 counts
Max reading 50.00 kRPM
Accuracy ±(0.5% +2 counts)
Duty cycle (PULSE)
Range 2% to 98%
Frequency range 15 Hz (1 Hz) to 30 MHz in continuous autoset
Pulse width (PULSE)
Frequency range 15 Hz (1 Hz) to 30 MHz in continuous autoset
Full scale reading 1000 counts
Amperes (AMP)
With current clamp Ranges Same as V dc, V ac, V ac+dc, or PEAK
Scale factors 0.1 mV/A, 1 mV/A, 10 mV/A, 100 mV/A, 400 mV/A, 1 V/A, 10 mV/mA
Accuracy Same as V dc, V ac, V ac+dc, or PEAK (add current clamp uncertainty)
Temperature (TEMP) with optional temperature probe
Range 200 °C/div (200 °F/div)
Scale factor 1 mV/°C and 1 mV/°F
Accuracy As V dc (add temp. probe uncertainty)
Decibel (dB)
0 dBV 1 V
0 dBm (600 Ω /50 Ω) 1 mW referenced to 600 Ω or 50 Ω
dB on V dc, V ac, or Vac+dc
Full scale reading 1000 counts
Crest factor (CREST)
Range 1 to 10
Full scale reading 90 Counts
Modes A to B, B to A
Range 0 to 359 degrees
Resolution 1 degree
Power (125B only)
Configurations 1 phase / 3 phase 3 conductor balanced loads (3 phase: fundamental component only, AUTOSET mode only)
Power factor (PF) Ratio between watts and VA range – 0.00 to 1.00
Watt RMS reading of multiplying corresponding samples of input A (volts) and input B (amperes)
Full scale reading 999 counts
VA Vrms x Arms
Full scale reading 999 counts
VA reactive (var) √((VA)2-W2)
Full scale reading 999 counts
Purpose To measure on pulse width modulated signals, like motor drive inverter outputs
Principle Readings show the effective voltage based on the average value of samples over a whole number of periods of the fundamental frequency
Accuracy As Vrms for sinewave signals


Input A to common
Ohm (Ω)
Ranges 123B and 124B 500 Ω , 5 kΩ, 50 kΩ, 500 kΩ, 5 MΩ, 30 MΩ
125B 50 Ω, 500 Ω , 5 kΩ, 50 kΩ, 500 kΩ, 5 MΩ, 30 MΩ
Accuracy ±(0.6% + 5 counts) 50 Ω ±(2% + 20 counts)
Full scale reading 50 Ω to 5 MΩ – 5000 counts, 30 MΩ – 3000 counts
Measurement current 0.5 mA to 50 nA, decreases with increasing ranges
Open circuit voltage <4 V
Continuity (Cont)
Beep <(30 Ω ±5 Ω) in 50 Ω range
Measurement current 0.5 mA
Detection of shorts of ≥1 ms
Measurement voltage @0.5 mA >2.8 V
@open circuit <4 V
Measurement current 0.5 mA
Polarity + on input A, – on COM
Capacitance (CAP)
Ranges 50 nF, 500 nF, 5 μF, 50 μF, 500 μF
Full scale reading 5000 counts
Measurement current 500 nA to 0.5 mA, increases with increasing ranges


Advanced meter functions
Zero Set Set actual value to reference
AutoHold (on A) Captures and freezes a stable measurement result. Beeps when stable. AutoHold works on the main meter reading, with thresholds of 1 Vpp for AC signals and 100 mV for DC signals.
Fixed decimal point Activated by using attenuation keys


Cursor Readout (124B and 125B)
Sources A, B
Single vertical line Average, min and max readout
Average, min, max and time from start of readout (in ROLL mode; instrument in HOLD)
Min, max and time from start of readout (in RECORDER mode; instrument in HOLD)
Harmonics values in POWER QUALITY mode.
Dual vertical lines Peak-peak, time distance and reciprocal time distance readout
Average, min, max and time distance readout (in ROLL mode; instrument in HOLD)
Dual horizontal lines High, low and peak-peak readout
Rise or fall time Transition time, 0%-level and 100%-level readout (manual or auto leveling; auto leveling only
possible in single channel mode)
Accuracy As oscilloscope accuracy


The recorder captures meter readings in Meter Recorder mode or continuously captures waveform samples in Scope Recorder mode. The information is stored on internal memory or on optional SD card (with the 125B or 124B).
The results are displayed as Chart recorder display that plots a graph of min and max values of Meter measurements over time or as a waveform recorder display that plots all the captured samples.
Meter readings
Measurement Speed Maximum 2 measurement/s
Record Size (min, max, average) 2 M readings for 1 channel
Recorded Time Span 2 weeks
Maximum number of events 1024
Waveform record
Maximum sample rate 400 K sample/s
Size Internal memory 400 M samples Recorded Time
Span internal memory 15 minutes at 500 μs/div
11 hours at 20 ms/div
Record Size SD card 1.5 G samples
Recorded Time Span SD card 11 hours at 500 μs/div
14 days at 20 ms/div
Maximum number of events 64


Power Quality (125B only)
Readings Watt, VA, var, PF, DPF, Hz
Watt, VA, var ranges (auto) 250 W to 250 MW, 625 MW, 1.56 GW
When selected: total (% r) ±(2% + 6 counts)
When selected: fundamental (% f) ±(4% + 4 counts)
DPF 0.00 to 1.00
PF 0.00 to 1.00, ±0.04
Frequency range 10.0 Hz to 15.0 kHz
40.0 Hz to 70.0 Hz
Number of Harmonics DC to 51
Readings / Cursor readings
(fundamental 40 Hz to 70 Hz)
Vrms / Arms /Watt Each harmonic from fundamental maybe selected for individual readings
Includes frequency of fundamental, phase Angle and K-factor (in Amp and Watt)


BusHealth tester (Fluke 125B only)
Type Subtype Protocol
AS-i NEN-EN50295
CAN ISO-11898
Interbus S RS-422 EIA-422
Modbus RS-232 RS-232/EIA-232
RS-485 RS-485/EIA-485
Foundation Fieldbus H1 61158 type 1, 31.25 kBit
Profibus DP EIA-485
PA 61158 type 1


Display Type 5.7-inch color active matrix TFT
Resolution 640 x 480 pixels
Waveform Display Vertical 10 div of 40 pixels
Horizontal 12 div of 40 pixels
Power External Via Power Adapter BC430
Input voltage 10 V DC to 21 V DC
Power consumption 5 W typical
Input connector 5 mm jack
Internal Via Battery Pack BP290
Battery power Rechargeable Li-Ion 10.8 V
Operating time 7 hours with 50% backlight brightness
Charging time 4 hours with test tool off,  7 hours with test tool on
Allowable ambient temp 0 to 40 °C (32 to 104 °F) during charging
Memory Internal memory can store 20 data sets  (screen waveform and setup) Micro SD card slot with optional SD card  (max size of 32 GB)
Mechanical Size 259 x 132 x 55 mm
(10.2 x 5.2 x 2.15 in)
Weight 1.4 kg (3.2 lb) including battery pack
Interface Optically isolated Transfer screen copies (bitmaps), settings and data
USB to PC/laptop OC4USB optically isolated USB adapter/cable, (optional), using FlukeView® software for Windows®.
Optional WiFi adapter Fast transfer of screen copies (bitmaps), settings and data to PC/laptop, tablet, smartphone, etc. A USB port is provided for attaching the WiFi dongle. Do not use the USB port with a cable for safety reasons.


Environmental MIL-PRF-28800F, Class 2
Temperature Battery Operation 0 to 40 °C (32 to 104 °F)
Power Adapter Operation 0 to 50 °C (32 to 122 °F)
Storage -20 to 60 °C (-4 to 140 °F)
Humidity (Operating) @ 0 to 10 °C (32 to 50 °F) Non-condensing
@ 10 to 30 °C (50 to 86 °F) 95%
@ 30 to 40 °C (86 to 104 °F) 75%
@ 40 to 50 °C (104 to 122 °F) 45%
Storage @ -20 to 60 °C (-4 to 140 °F) Non-condensing
Altitude Operating at 3 km (10,000 feet) CAT III 600 V
Operating at 2 km (6,600 feet) CAT IV 600 V
Storage 12 km (40,000 feet)
EMC electromagnetic compatibility International IEC 61326-1: Industrial, CISPR 11:  Group 1, Class A
Korea (KCC) Class A Equipment (Industrial Broadcasting & Communication Equipment)
USA (FCC) 47 CFR 15 subpart B. This product is considered an exempt device per clause 15.103.
Wireless radio with adapter Frequency range 2412 MHz to 2462 MHz
Output power <100 mW
Enclosure protection IP51, ref: EN/IEC60529
Safety General IEC 61010-1: Pollution Degree 2
Measurement IEC 61010-2-033: CAT IV 600 V/CAT III 750 V
Max. input voltage input A and B Direct on input or with leads 600 Vrms CAT IV for derating
With Banana-to-BNC Adapter BB120 600 Vrms for derating
Max. floating voltage from any terminal to ground 600 Vrms Cat IV, 750 Vrms up to 400 Hz

*Not all models are available in all countries. Check with your local Fluke representative.



Model Name Description
Fluke 125B Fluke 125B Industrial ScopeMeter® Hand-Held Oscilloscope (40 MHz)
Fluke 125B/S Fluke 125B/S Industrial ScopeMeter® Hand-Held Oscilloscope (40 MHz)
Fluke 124B Fluke 124B Industrial ScopeMeter® Hand-Held Oscilloscope (40 MHz)
Fluke 124B/S Fluke 124B/S Industrial ScopeMeter® Hand-Held Oscilloscope (40 MHz)
Fluke 123B Fluke 123B Industrial ScopeMeter® Hand-Held Oscilloscope (20 MHz)
Fluke 123B/S Fluke 123B/S Industrial ScopeMeter® Hand-Held Oscilloscope (20 MHz)


Cables & Hardware
Model Name Description
Fluke OC4USB Fluke OC4USB USB Interface Cable
Current Clamps
Model Name Description
Fluke 80i 110s Fluke 80i-110s AC/DC Current Clamp
Fluke i1000s Fluke i1000s AC Current Probe
Fluke i1010 Fluke i1010 AC/DC Current Clamp
Fluke i200s Fluke i200s AC Current Clamp
Fluke i30 Fluke i30 AC/DC Current Clamp
Fluke-i3000s Fluke i3000s AC Current Clamp
Fluke i3000s Flex 24 Fluke i3000s Flex-24 AC Current Clamp, 610 mm (24 in.)
Fluke i3000s Flex 36 Fluke i3000s Flex-36 AC Current Clamp, 915 mm (36 in.)
Fluke-i310s Fluke i310s Current Probe
Fluke i400 Fluke i400 AC Current Clamp
Fluke i410 Fluke i410 AC/DC Current Clamp
Fluke i5S Fluke i5S AC Current Clamp


Knowledge and Information

123B/124B/125B Users Manual Download
123B/124B/125B Users Manual Supplement Download
123B/124B/125B Bushealth Addendum Download
123B/124B/125B Calibration Manual Download
123B/124B/125B Calibration Manual Supplement Download
123B/124B/125B Safety Sheet Download
123B/124B/125B Statement of Memory Volatility Download
Application Notes
ScopeMeter® 120B Recording Mode Download
Data Sheets
Fluke ScopeMeter 120B Series Test Tools Data Sheet Download
Download the App