VSD Digital Multimeter ( HTC – DM-87 )

Description

The HTC DM‑87 Digital Multimeter is a rugged 4½‑digit handheld tool (5,999‑count resolution) built for precision diagnostics in industrial, laboratory, HVAC, electrical, and electronics servicing. It features True‑RMS measurement and advanced VSD (variable frequency) handling, delivering accurate readings across AC and DC parameters. Designed for clarity, the compact 23 mm-digit backlit LCD offers large, legible output alongside an analog bar graph display, data hold, and MAX/MIN value capture—while avoiding accidental shutdown during active operation.

Precision Measurement and Ranges

The DM‑87 measures DC voltage from 0.1 mV to 1000 V, with high accuracy ratings: ±0.5% +4 digits in the lower ranges and ±1.0% +3 digits at high voltage levels, thanks to its 10 MΩ input. AC voltage extends up to 750 V RMS with ±0.8% +10 digits accuracy (50 Hz–5 kHz) and ±1.5% +10 digits at higher frequencies—making it ideal for motors, drives, and control systems. It applies True‑RMS detection and supports variable frequency voltages (VSD) up to 200 Hz.

The meter offers wide current ranges: 0.1 µA to 20 A for both DC and AC, with fused protection on lower ranges and high-current durability. DC current accuracy is ±1.0% +10 digits, while AC (True‑RMS) accuracy reaches ±1.5% +20 digits (40 Hz–400 Hz).

Its resistance range spans up to 30 MΩ, with a resolution starting at 0.1 Ω and accuracy of ±0.8% +3 digits. The meter supports capacitance measurements from 10 pF to 2,000 µF at ±2.5% +5 digits.

For frequency testing, it covers 5 Hz to 30 MHz with ±0.5% +4 digits precision, while temperature via Type‑K probe spans ‑40 °C to 1000 °C with ±0.8% +4 digits accuracy (≤0 °C) and ±1.5% +15 digits above 400 °C.

Advanced Functionality

Beyond measurement, the DM‑87 delivers VSD-compatible voltage detection, diode testing, transistor hFE testing (0–1000 gain), and continuity buzzer (triggers under ~30 Ω ±10 Ω). It features data hold, range lock (no auto OFF during use), MAX/MIN/AVG capture, relative mode (REL), analog bar graph, and backlight illumination. Sampling refreshes at ~3 times/sec for real-time diagnostics. Input protection and auto-overload shutdown safeguard the instrument.

Build & Usability

Compact and ergonomic, the unit measures 185 × 93 × 35 mm, weighs around 290 g, and runs on a single 9 V battery (6F22). It includes auto‑power‑off (~15 min), a low battery alert (<5.5 V), and compliance with IEC 61010 CAT II safety. The dual-integral A/D design ensures high stability and linearity across measurements.

Accessories & Use Cases

Each DM‑87 ships with standard accessories: test leads, TP‑01 temperature probe, crocodile clip, user manual, and battery—ready for immediate deployment. Typical applications include voltage and current troubleshooting in electrical wiring, electronics repair, HVAC control validation, power frequency/duty‑cycle testing, filter and motor diagnostics, sensor and thermocouple evaluation, and component inspection. This multimeter is especially suited for technicians working with VSD motors, variable-frequency control circuits, and HVAC systems requiring accurate frequency‑dependent reading.

Key Highlights

• True RMS AC/DC measurement (up to 1000 V DC / 750 V AC; 20 A current)

• VSD frequency‑voltage support and accurate duty cycle detection

• High-resolution frequency (up to 30 MHz) and temperature range (–40 to 1000 °C)

• Diode, transistor hFE (0–1000), continuity buzzer, relative mode, analog bar-graph

• Large 23 mm backlit display with MAX/MIN/AVG/data hold; no auto-off during active use

• Durable and safe: IEC CAT II compliance, overload protection, anti-shock design

• Compact, ergonomic, with included probe, leads, clip and battery

In summary, the HTC DM‑87 Digital Multimeter is a professional-grade tool engineered for high-precision, versatile measurement across voltage, current, frequency, capacitance, temperature, and transistor/diode testing. With True RMS detection, robust VSD support, and advanced logging functions in a rugged form factor, it is ideal for electricians, HVAC technicians, and electronics professionals seeking accuracy, safety, and performance in one reliable handheld meter.