Wide Range 3 mΩ to 3 MΩ Portable DC Resistance Meter with 0.1 μΩ Resolution for Equipment Maintenance and Quality Control

SKU: RM3548 Category:


Hioki DC resistance meters measure a broad range of resistance values at a high level of precision. The RM3548 is a high-precision, portable resistance meter capable of measuring resistance levels from microohms to megaohms, and is intended primarily for use in testing and maintenance of large equipment, for example, measuring the winding and weld resistances in large motors.

Key Features
• 0.02 % basic accuracy, 0.1 μΩ max. resolution, 1 A max. testing current, 1A max. testing current
• Measure from 0.0 µΩ (testing current 1 A) to 3.5 MΩ
• Easily record up to 1,000 data points in memory simply by applying the instrument’s probes
• Smoothly capture temperature-rise test data using interval measurement
• Portable design is ideal for maintenance and testing of large equipment

Model No. (Order Code)

USB 2.0
3 year



Product Video

Portable resistance tester that’s ideal for low-resistance measurement and testing of large transformers and motors

This resistance tester features a portable design that’s easy to use when performing maintenance work in the field. You can wear the instrument over your neck with the included strap, leaving both hands free to hold the clip-type leads while making measurements. The instrument can be powered by eight AA alkaline batteries for about 10 hours of measurement. (Operating time varies with measurement conditions.)

Reduce the effects of thermoelectromotive force with the offset voltage correction

Thermoelectromotive force refers to the potential difference that occurs at junctions between different metals (see figure). Specifically, the phenomenon occurs where measurement probes and measurement targets come into contact, and at connections between measuring instruments and measurement leads. The magnitude of this thermoelectromotive force varies with the temperature of the measurement environment, increasing as the temperature difference grows. The RM3548 includes an offset voltage correction function that applies the measurement current in both the positive and negative directions and then uses the resulting detected voltages to eliminate the effects of thermoelectromotive force.

Correct resistance values, which vary with temperature, to a reference temperature with the temperature correction function

Temperature correction functions can convert readings to resistance values at a user-specified reference temperature and display the results, even for materials such as copper wire whose resistance varies with temperature. The RM3548’s temperature correction function converts the measured resistance value Rt at the current temperature t to the resistance value Rt0 at the reference temperature t0, as shown in the figure. The Temperature Sensor Z2002 (which comes with the RM3548) is used to perform temperature correction.

Basic specifications (Accuracy guaranteed for 1 year, Post-adjustment accuracy guaranteed for 1 year)

Resistance range3 mΩ (3.5000 mΩ display Max., 0.1 µΩ resolution) to 3 MΩ range (3.5000 MΩ display Max., 100 Ω resolution), 10 steps
Measurement accuracy: ±0.020 % rdg. ±0.007 % f.s.
Testing current[at 3 mΩ range] 1 A DC to [at 3 MΩ range] 500 nA DC
Open-terminal voltage5.5 V DC max.
Temperature measurement-10.0 to 99.9°C, accuracy: ±0.50°C (Temperature Sensor Z2002 and RM3548 combined accuracy)
Measurement speedFixed
Display refresh rateWithout OVC: approx. 100ms, With OVC: approx. 230ms
FunctionsTemperature correction, temperature conversion, offset voltage compensation (OVC), comparator (ABS/REF%), length conversion, judgment sound setting, auto hold, auto power save (APS), 
Averaging, panel store/panel load, USB communication interface (RM3548 internal memory is recognized as a mass storage device when connected to a PC)
Memory storageNumber of recordable data points: (manual/auto) Up to 1,000, (interval) Up to 6,000; Interval: 0.2 to 10.0s (0.2s steps); Acquisition of data from memory: display, USB mass storage (CSV, TXT files)
Power supplyLR6 (AA) Alkaline batteries ×8, Continuous use: 10 hours (Under our company’s conditions), Rated power consumption: 5 VA max.
Dimensions and mass192 mm (7.56 in) W × 121 mm (4.76 in) H × 55 mm (2.17 in) D, 770 g (27.2 oz)
AccessoriesClip type lead L2107 ×1, Temperature sensor Z2002 ×1, LR6 Alkaline battery ×8, Instruction manual ×1, USB Cable(A-to-mini B type) ×1, Strap ×1, Spare fuse ×1


Catalog: RESISTANCE METER RM3544, RM3548

Catalog: Motor Measurement Applications

User Guides

Technical Note: Shunt Resistor Measurement Vol.5

Technical Note: Wide or Thick Resistor Measurement Vol.4

Technical Note: Introduction to Resistance Measurement Vol.1

Technical Note: Resistance Measurement of Busbar Welds Vol.3





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