Digital multimeter BM839 TRMS 4 1/2 digits VFD & Hz BeepLit ACV 20kHz 102189

Application and Key Features in Industry

This digital multimeter is a tool designed to solve complex problems in industrial automation, power distribution, and the maintenance of electromechanical equipment. Its core is a True RMS circuit with a bandwidth up to 20 kHz, allowing for precise reading of RMS values even in circuits with distorted waveforms typical of inverters and drives. Thanks to this, the user no longer has to rely on estimates – the meter displays the actual voltage or current value, regardless of the waveform shape.

It is worth noting the unique VFD-ACV and VFD-Hz functions, which integrate voltage and frequency measurement into a single reading. This is invaluable when diagnosing systems controlled by inverters, where traditional meters often fail due to interference. The low-pass filter (LPF) effectively filters out high-frequency noise, ensuring a stable result even in difficult electromagnetic conditions.

Safety and Ergonomics

Operator safety is a priority here. The device meets high safety standards: CAT III 1000V and CAT IV 600V, making it suitable for work in main switchboards and industrial installations. An additional safety feature is resistance to voltage surge impulses up to 8 kV (1.2/50 µs) and current inputs protected by HBC fuses.

For the installer, the Beep-Jack™ function may prove crucial. This system actively detects incorrect connection of measurement leads to input jacks and warns of this audibly and visually before damage to the meter or electric shock occurs. This is a simple but extremely effective barrier against human error during rapid diagnostics.

Ergonomics has been refined in every detail:

• A large, dual LCD display with backlight allows simultaneous reading of the main result (up to 6,000 or 20,000 counts) and a bargraf updated 40 times per second – this allows tracking of rapid value changes in real time.
• Fast sampling (5 times per second for the main screen) ensures smooth reading without delays.
• The BeepLit™ function in continuity mode automatically backlights the screen upon detecting a short circuit or closed circuit, facilitating work in poorly lit areas (e.g., behind a switchboard).
• The set includes a solid holster that protects the device from drops and dust while carrying it around a construction site or production hall.

Advanced Measurement Modes and Analytical Capabilities

The meter offers a wide range of analytical functions that accelerate the fault diagnosis process. The CREST-MAX (PEAK HOLD) mode records peak values lasting only 5 ms, which is essential for detecting short-term overvoltages or impulse interference. Additionally, MAX/MIN recording modes and relative measurements Δ are available, allowing for quick comparison of the current reading with a baseline value without the need to manually record data.

In terms of basic measurements, the device handles DC and AC voltage up to 1000 V (True RMS), DC and AC current up to 20 A (True RMS), resistance up to 60 MΩ, and conductance up to 60 nS. It also includes the ability to measure capacitance up to 20 mF or temperature in a wide range from -40°C to 1090°C (with a thermocouple probe). AC frequency can be measured with an LPF filter up to 100 kHz.

Thanks to automatic compensation of measurement lead resistance, low-resistance measurement results are significantly more accurate – the meter subtracts the resistance of the cables themselves from the final result. The automatic power-off function saves battery energy during long breaks in work, and the HOLD button allows "freezing" the result on the screen for easier recording or analysis after the measurement is completed. It is worth remembering the display resolution reaching up to 20,000 counts in counting mode and the device's resistance to environmental conditions resulting from its construction and CAT III/CAT