Digital multimeter BM789 AC/DC 100kHz TrueRMS 102222

Professional tool for diagnosing complex systems

In industrial environments where motors, PLC controllers, or power distribution systems are driven, standard meters often fail to read distorted waveforms. The BM789 multimeter solves this problem by offering True RMS measurement with a wide bandwidth up to 100 kHz. This allows technicians to rely on accurate results even in circuits with VFDs (Variable Frequency Drives) or switching power supplies, where traditional average-responding meters provide erroneous values. The device not only measures voltage and current but can distinguish useful signals from noise or phantom voltages, which is crucial when troubleshooting complex automation installations.

Safety and intelligent protection against operator errors

Working under voltage requires not only knowledge but also equipment that "thinks" for the user. This model is equipped with the Beep-Jack™ system, which provides acoustic and visual warnings against attempting to connect leads to the wrong socket – a simple feature that eliminates the risk of short circuits during current or voltage measurements. Safety is confirmed by CAT III 1000V / CAT IV 600V certification, allowing safe work in main distribution boards and at power sources.

For installers, the LoZ (Low Input Impedance) function is also important. In older installations or where electromagnetic interference occurs, so-called phantom voltages often appear – false readings on the meter. The LoZ mode eliminates these errors, showing the actual voltage value under load. Additionally, the AutoV mode automatically detects the signal type (AC or DC) and switches ranges without the need for manual setting changes by the operator, speeding up work during quick diagnostics.

Advanced measurement functions and data analysis

This multimeter goes beyond basic measurements, offering a set of analytical tools in one device. The 60,000-count LCD display refreshes 5 times per second, and the bargraf operates at 50 Hz – ideal for observing rapidly changing signals while maintaining DC voltage measurement accuracy at 0.03%. Functions dedicated to VFD drives (VFD-ACV and VFD-Hz) allow precise measurement of voltage and frequency at inverter outputs without the need for additional filters.

Direct reading of current in a 4-20 mA loop with percentage (%) display facilitates the calibration of process sensors. The integrated NCV (EF) sensor with adjustable sensitivity (Hi/Lo) allows quick checking for the presence of AC voltage without touching live parts. MAX/MIN/AVG modes and peak value storage (CREST/PEAK HOLD) with a sampling time of 0.25 ms allow capturing transient voltage or current spikes that cause failures in electromechanical devices.

Key device parameters include a wide measurement range: AC/DC voltage up to 1000 V and AC/DC current up to 10 A. The meter handles resistance up to 60 MΩ, capacitance up to 10 mF, and conductance up to 99.99 nS. In the temperature range, the device works with thermocouple probes covering a range from -2°C to +199°C (depending on the probe used), and AC frequency measurement reaches 50 kHz. Duty Cycle can be measured in the range from 0.1% to 99.9%. All this data is available thanks to the device's high level of overvoltage and overload protection.

Practical field application

Thanks to the AutoHold function, which automatically locks a stable reading after the measurement is completed (even after disconnecting the probes), technicians can work alone in hard-to-reach places without the risk of losing the result before recording it. The RealRead™ function filters out unstable readings ("blind measurements"), displaying only significant data in real-time – saving time when diagnosing vibrating or flickering circuits. Continuity and diode tests with the BeepLit™ function provide immediate acoustic and visual feedback even in dark distribution boards. This device is designed with the ergonomics of industrial electrician and automation technician work in mind simultaneously.