Mitsubishi MR-J4-70B servo amplifier — 0.75 kW, 200V class, SSCNET III/H
The MR-J4-70B is a 0.75 kW servo amplifier in Mitsubishi's MR-J4 series, running on three-phase or single-phase 200–240 VAC mains at 50/60 Hz. It drives a compatible servo motor via the SSCNET III/H motion network at communication cycles of 0.222 ms, 0.444 ms, or 0.888 ms — tight enough for synchronized multi-axis lines. Rated output current is 5.8 A, with a main circuit input draw of 3.8 A. The built-in dynamic brake handles emergency stops without an external resistor bank for most load inertia ratios. Functional safety is covered by STO per IEC/EN 61800-5-2, with a PFH of 6.4 × 10⁻⁹ 1/h. The STO input responds in 8 ms or less from signal-off to energy cutoff, and it accepts test pulse inputs from 1 Hz to 25 Hz with a max off-time of 1 ms — clean integration into a safety PLC or light curtain circuit.
Elevation limit is 2000 meters above sea level; above that, derate for air density and creepage distances. Vibration tolerance is 5.9 m/s² from 10 to 55 Hz in X, Y, Z — fine for panel-mounted installation on a machine base, but not for direct mounting on a high-vibration axis. The USB port on the front panel connects to a PC running MR Configurator 2 for setup, tuning, and drive recorder playback. Two analog monitor channels let you scope torque, speed, or position on a scope without extra DAQ hardware.
Built-in advanced vibration suppression, adaptive and robust filters, auto tuning, one-touch adjustment, and the tough drive function mean the amplifier handles load resonance and stiffness changes without an external filter or a tuning marathon. The drive recorder captures waveform data for post-mortem analysis on intermittent faults. Full closed-loop control is supported via a 2-wire serial encoder interface on the motor end, and the amplifier outputs ABZ-phase encoder pulses for an external controller or counter.