Meatest M642 Programmable Resistance Decade

The Meatest M642 is a wide‑range, programmable resistance decade box designed for industrial calibration, automated testing and laboratory applications. Unlike electronic simulators, the M642 uses real precision resistors switched by high‑quality relays, ensuring predictable behaviour, long‑term stability and full traceability — essential for accurate measurements and reliable quality control. Covering a range from 100 mΩ to 22 MΩ, with basic accuracy down to 0.02% and a load capacity of 5 watts, the M642 combines robustness with precision. Fast switching, excellent linearity and a rich set of interfaces make it suitable for both manual and automated workflows.

Real resistors, real accuracy

The M642 is built from stable, high‑power resistors capable of continuously dissipating 5 W under load. There is no residual resistance, no hidden offsets and no corrections required from the user. The value shown on the display is the value delivered at the terminals — including all relevant uncertainties. Resolution is fine enough for precision work, while stability and linearity are maintained across the entire range. With a switching time below 6 ms, the M642 is also suitable for dynamic testing and automated sequences.

Smart features for modern calibration

The M642 goes far beyond traditional decade boxes. Its firmware supports custom units, time sequences, RTD simulation and conversions into temperature, distance or force. This allows users to work directly in the physical quantity relevant to their application.

Supported RTD scales include:

• > Platinum: IPTS‑68, ITS‑90, 1.3916, 1.3926
• > Nickel: Ni10–Ni20000
• > Custom curves

Simulation accuracy ranges from 0.1 to 1 °C, depending on sensor type and temperature range.

Fully programmable and automation‑ready

All functions can be controlled locally via the large LCD display or remotely through:

• > RS‑232
• > USB
• > LAN
• > GPIB

This makes the M642 easy to integrate into production lines, automated calibration systems or test benches. For resistance‑based sensors — such as RTDs, load cells, potentiometric devices or transmitters — the M642 can significantly reduce testing time.

AC performance and frequency response

The M642 can also be used for AC applications. Typical AC‑DC differences are specified up to 10 kHz, giving users clear insight into the decade’s behaviour under alternating signals. At low frequencies the deviations remain small; at higher frequencies impedance effects become more pronounced, as expected from physical resistors.

Construction, interfaces and usability

The instrument features a robust metal enclosure and gold‑plated 4 mm terminals for reliable connections. With dimensions of 390 × 128 × 310 mm and a weight of 4.5 kg, the M642 is compact enough for bench use yet durable enough for industrial environments. The Meatest M642 is a versatile, accurate and fully programmable resistance decade box that combines real resistors with modern functionality. With its wide range, high load capacity, advanced firmware and extensive interface options, it is an excellent choice for laboratories and production environments requiring reliable and traceable resistance simulation.