MR-J4-200A is a 2 kW pulse-train input servo amplifier from Mitsubishi Electric’s MELSERVO-J4 series, designed for high-precision positioning and speed control of HG-SR, HG-MR, and HG-KR series servo motors in standalone or PLC-coordinated motion applications. The «200» suffix identifies the 2 kW (2,000 W) power class, and the «A» designates the general-purpose pulse input interface variant — accepting pulse train commands in PULSE/SIGN or CW/CCW format from any PLC, motion controller, or CNC system capable of high-speed pulse output, without requiring SSCNET III/H network infrastructure. Atlantech Drives holds stock of the MR-J4-200A. Contact us for fast worldwide delivery and competitive pricing.
What Is the MR-J4-200A?
The MR-J4-200A is the 2 kW member of the MELSERVO-J4 general-purpose (pulse input) servo amplifier family, bridging the gap between the MR-J4-100A (1 kW) and the MR-J4-350A (3.5 kW) in the A-series power range. At 2 kW, this amplifier is the standard specification for single-axis servo drives in medium-duty applications such as rotary indexing tables, precision linear actuators, CNC router axes, and label application heads where the FX3U or Q-series PLC pulse output provides the position command. The MR-J4-200A operates on three-phase 200–240 V AC (single-phase operation is also supported for the 200A frame, subject to output current derating) and delivers up to 9.5 A continuous output current with a peak of 28.5 A for high-torque acceleration. The amplifier incorporates Mitsubishi’s one-touch auto-tuning algorithm, real-time adaptive vibration suppression (MAVG — Machine Adaptive Vibration suppression Gain), and a 22-bit encoder interface for absolute position feedback when paired with a compatible HG-series motor with absolute encoder option and MR-BAT6V1SET battery.
Key Technical Specifications
- Rated Output Power: 2 kW (2,000 W)
- Power Supply: Three-phase or single-phase 200–240 V AC, 50/60 Hz
- Rated Output Current: 9.5 A (continuous)
- Peak Output Current: 28.5 A (instantaneous, 3× rated)
- Command Interface: Pulse train input (max. 4 Mpps differential line driver / 200 kpps open collector)
- Pulse Input Formats: PULSE/SIGN, CW/CCW, A/B quadrature (2-phase)
- Encoder Interface: 22-bit absolute/incremental (serial communication to HG-series encoder)
- Analogue Monitor Outputs: 2 channels (speed, torque, position error — configurable)
- Digital I/O: 10 inputs / 6 outputs (programmable function assignment)
- Safety Function: STO (Safe Torque Off) — IEC 61800-5-2, SIL2, PLd
- Auto-Tuning: One-touch tuning, real-time adaptive tuning
- Regenerative Option: Built-in regenerative resistor + external option (MR-RB series)
- Communication: USB (MR Configurator2), RS-422 (parameter unit / GOT HMI)
- Dimensions (W × H × D): 55 × 170 × 168 mm
- Weight: Approx. 1.5 kg
Architecture & Design Overview
The MR-J4-200A implements a full digital servo control loop with a position loop update rate of 0.444 ms and a current (torque) loop bandwidth exceeding 2.5 kHz, providing response characteristics that rival dedicated motion controller architectures while accepting simple pulse train commands from any external source. The 22-bit serial encoder interface (4,194,304 counts per revolution) communicates with the motor encoder over a single shielded twisted-pair cable using Mitsubishi’s proprietary high-speed serial protocol, eliminating the multiple-wire parallel encoder cables required by older servo systems and significantly reducing wiring complexity in multi-axis installations. The amplifier’s adaptive resonance suppression filter continuously identifies mechanical resonances in the connected load (gear backlash, belt compliance, table flex) and automatically inserts notch filters at the identified resonant frequencies — this Machine Resonance Suppression (MRS) function reduces the need for manual gain tuning in applications with variable load dynamics such as robotic arms handling different payload weights. The STO (Safe Torque Off) function is implemented in hardware-redundant circuitry meeting SIL2/PLd requirements; it is activated by removing the 24 V DC signal from the STOC and STO1/STO2 input terminals, cutting gate drive to the IGBT output stage without requiring a software command — enabling integration into functional safety architectures (EN ISO 13849-1) without a dedicated safety PLC relay for the servo axis.
Replacement & Upgrade Notes
The MR-J4-200A is the direct functional upgrade path from the MR-J3-200A for systems being modernised from the MELSERVO-J3 to J4 generation. The mechanical mounting dimensions (55 mm width, 170 mm height) are identical between the MR-J3-200A and MR-J4-200A, allowing a panel retrofit without cabinet modification. However, the encoder cable connector on the amplifier side has changed between J3 and J4 — the MR-J4-200A requires a J4-compatible encoder cable (MR-J4ENSCBL□M-A/B-L series) rather than the J3 cable; Mitsubishi supplies conversion cables for motors being reused from J3 systems (HC-SF, HC-RF, HC-UF series motors with older encoders). When upgrading, note that the MR-J4 parameter numbering differs from MR-J3 — parameters must be re-entered from the J3 backup using the MR-J3 to MR-J4 parameter correspondence table in the MR-J4-A Servo Amplifier Instruction Manual appendix. MR Configurator2 includes a project conversion function that automates most parameter migration, but parameters related to vibration suppression and auto-tuning should be re-optimised from scratch on the J4 platform rather than ported directly, as the J4’s improved tuning algorithms produce better results when run natively than when initialised from J3 gain values.
Frequently Asked Questions
Q: Can the MR-J4-200A operate on single-phase 200 V AC input instead of three-phase?
A: Yes, with derating. The MR-J4-200A supports single-phase 200–240 V AC input, but Mitsubishi specifies that the continuous output current must be derated to 9.5 A × 0.85 = approximately 8.1 A when operating on single-phase supply, due to the higher ripple current on the DC bus capacitors with single-phase rectification. For applications where the motor operates below this derated current limit continuously, single-phase operation is acceptable. Confirm the derating factor from Table 1.3 of the MR-J4-A Servo Amplifier Instruction Manual (SH-030018) for the specific operating conditions.
Q: What is the maximum pulse input frequency supported by the MR-J4-200A, and which input type achieves it?
A: The MR-J4-200A accepts pulse inputs at up to 4 Mpps (4,000,000 pulses per second) when using differential line driver input (RS-422, 5 V). Open-collector pulse inputs (24 V DC NPN) are limited to 200 kpps — a 20× lower maximum frequency. For high-speed positioning applications requiring fine resolution at high velocities, always use a differential line driver pulse source such as the FX3U-2HSY-ADP adapter or the QD77MS4 Simple Motion Module pulse output channels.
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