Hioki RM3548 Portable Resistance Meter

Key Features At A Glance

• Four-terminal (4-wire) DC resistance measurement from microohms to 3.5 MΩ across the series
• 0.02% basic measurement accuracy across the RM3544/RM3548 series
• No warmup period and no zero adjustment — accuracy guaranteed immediately at power-on
• Temperature correction to a reference temperature (requires Z2001 or Z2002 temperature sensor)
• Comparator PASS/FAIL judgment via user-selectable tones of at least 85 dB plus optional LED Comparator Attachment
• Available as bench-top (RM3544/RM3544-01) or portable battery-powered (RM3548) configurations
• Maximum measurement current ranges from 300 mA (RM3544) up to 1 A (RM3548) across the series
• Optional EXT I/O, RS-232C, and USB interfaces for automated production lines (RM3544-01)

The HIOKI RM3544, RM3544-01, and RM3548 are four-terminal DC resistance meters built to measure the winding resistance of devices such as motors and transformers, the contact resistance of power contacts such as relays and switches, and the DC resistance of fuses, resistors, and substrates such as conductive rubber and sheets. They perform these measurements quickly and at a high level of accuracy using four-terminal measurement. The RM3544 is a bench-top instrument suited to adjustment and testing on production lines as well as acceptance inspections, while the RM3548 is a portable solution for measuring resistance values ranging in magnitude from microohms to megohms, making it suited to production, maintenance, repair, and operation of large equipment.

The listed application targets span motors, solenoids, choke coils, transformers, and wire harnesses; contacts, relay contacts, and switches; conductive rubber and paint; fuses, resistors, heaters, wires, and welds; and large motors and large transformers. The series is also applied to temperature-rise tests on motors, choke coils, and transformers, and the RM3548 is used to verify continuity of vehicle grounding lines and the conductivity of aircraft fuselages, including fuselage welds and caulking. On the bench, the RM3544/RM3544-01 is positioned for adjustment, testing, and acceptance inspections on production lines.

ValueTronics supports the RM3544/RM3548 line from our own 20,000 sq ft secure warehouse at 1675 Cambridge Drive in Elgin, Illinois, where we stock and hold our inventory rather than sourcing it on demand. Holding our own stock in Elgin lets us match the right instrument and condition to your application and ship it without the delays of a special-order supply chain.

Compare Other Models in This Series

HIOKI presents the RM3544, RM3544-01, and RM3548 as a line-up of four-terminal resistance meters that share a 0.02% basic accuracy and measurement up to 3.5 MΩ, while differing in form factor and measurement current. The RM3544/RM3544-01 is the bench-top member, described as easy to use with high-accuracy and suited to adjustment and testing on production lines and acceptance inspections. The RM3548 is the high-accuracy portable member that measures from microohms to megohms for maintenance and testing of large equipment.

Within the broader HIOKI resistance-meter range, these models are positioned for production-line and MRO work using four-terminal measurement. Each model below is its own configuration with its own accessory set and interface options, and the comparison table that follows lays out the resolution, current, range count, and connectivity that distinguish them.

Each new model linked below is its own dedicated product page with condition-matched pricing, so you can select the exact configuration and condition that fits your application and budget.

The RM3544-01 is the member of the line that adds the EXT I/O handler interface with NPN/PNP polarity selection together with RS-232C and USB communication, completing one measurement-to-judgment cycle in as little as 18 ms for integration with automatic testing equipment. The base RM3544 shares the same measurement performance but does not include the EXT I/O or communication interfaces.

The differences across the line follow form factor and measurement current. The RM3544/RM3544-01 is bench-top, draws universal AC power, offers a maximum resolution of 1 μΩ and a maximum measurable current of 300 mA across 9 ranges, and the -01 variant adds EXT I/O, RS-232C, and USB. The RM3548 is portable and battery-powered (eight AA cells), offers a maximum resolution of 0.1 μΩ and a maximum measurable current of 1 A across 10 ranges, adds offset voltage compensation and 70 V DC overvoltage protection, and provides a read-only USB mass storage interface.

All three members hold the same 0.02% basic accuracy and the same 3.5 MΩ upper measurement limit, so the selection between them turns on whether the work is bench-based production-line testing with optional automation (RM3544/RM3544-01) or portable measurement of large equipment requiring higher current and finer resolution (RM3548). Refer to the comparison table for the per-model resolution, current, range count, and interface details.

Four-terminal measurement separates the current-injection and voltage-sensing paths to remove lead and contact resistance from the reading.

The RM3544 is a bench-top instrument with a footprint of 215 × 166 mm, approximately 25% smaller than the previous 3540, which frees bench space and allows it to be embedded in other equipment. It offers 1 µΩ maximum resolution, 0.02% basic accuracy, and a 300 mA maximum measurement current across nine ranges, with a universal 90-to-264 V AC input and automatic 50/60 Hz line-frequency detection.

Additional differences in specifications beyond the few shown above are not listed here — see each model's full specifications below.

Accessories Supplied

• CLIP 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

Replaces: per the manufacturer, this model replaces 3540.

Product Core & Specifications

Important: Proper operation of the RM3544 is not guaranteed when using test leads (test probes) that lack guard terminals, such as those used with the Resistance HiTester 3541 or mΩ HiTester 3540; use the test leads indicated in the RM3544 accessory and option documentation.

Important: The temperature correction function requires a temperature sensor (Z2001 for the RM3544/RM3544-01 or Z2002 for the RM3548). The Z2001 is not included in the RM3544/RM3544-01 standard accessories and must be ordered separately; the Z2002 is supplied with the RM3548.

Important: On the RM3548, the temperature conversion function cannot be used simultaneously with the temperature correction function and the length conversion function.

Recommended pairing: add the HIOKI Z2001 temperature sensor (RM3544/RM3544-01) or Z2002 (RM3548) to enable the temperature correction function that converts readings to a reference temperature.

About this New unit

This is a brand-new, factory-sealed unit, supplied exactly as it arrives from the manufacturer and backed by the full manufacturer warranty. For the exact configuration, available options, included accessories, or current lead time for your application, our Test Architects can confirm the details before you order.

ValueTronics supplies both new and used test and measurement equipment. New units ship factory-sealed, exactly as received from the manufacturer; every used unit is inspected and functionally verified in-house at our 20,000 sq ft secure facility in Elgin, Illinois before it ships. Our Test Architects can help you select the condition, calibration, and configuration that fit your application.

Please review the Manufacturer's Data Sheet to verify published specifications. Feedback on this webpage is always welcome — please reach out to your Test Architect at any time for questions or concerns. Thank you, we truly appreciate you being our customer.