The MR-J4-100A is Mitsubishi Electric’s 1 kW MELSERVO-J4 series servo amplifier for 200 V single-phase or three-phase AC power supply with pulse train position command input — the most widely specified MR-J4-A model for general-purpose single-axis servo positioning in CNC auxiliary axes, packaging machine servo drives, and industrial automation where 1 kW of continuous servo power with pulse train command interface from an existing positioning module or CNC controller provides the right combination of capability and economy. Atlantech Drives holds stock of the MR-J4-100A. Contact us for fast worldwide delivery and competitive pricing.
What Is the MR-J4-100A?
The MR-J4-100A is a MELSERVO-J4 series servo amplifier providing 1 kW (1,000 W) continuous output power for Mitsubishi HG-SR102, HG-SR1024, HG-KR13, and equivalent 1 kW servo motors with 22-bit multi-turn absolute encoders, accepting position command pulses from a host controller via open-collector or differential RS-422A pulse input at up to 4 Mpps. As the 1 kW model in the MR-J4-A pulse train series, the MR-J4-100A is the most commonly stocked MR-J4 servo amplifier — the 1 kW power class addresses the single most prevalent servo axis power requirement across machine tool, packaging, conveyor, and robotic applications. The amplifier implements the full MR-J4 servo control feature set: 22-bit multi-turn absolute encoder support eliminating homing at power-up, Advanced Vibration Suppression Control II with automated dual notch filter resonance detection, dual-channel STO safety function compliant with IEC 61800-5-2 SIL2 and EN ISO 13849-1 PLe, and MR Configurator2 USB commissioning interface for one-touch auto-tuning and waveform monitoring. The 55 mm compact housing enables dense multi-axis panel layouts alongside other MR-J4-70A (750 W) and MR-J4-200A (2 kW) models of compatible width. For new machine designs requiring multi-axis coordinated motion, the MR-J4-100B (SSCNET III/H variant of the same power stage) provides the same 1 kW capability with SSCNET III/H network command for tighter synchronisation — the MR-J4-100A is the correct specification when the host controller outputs pulse train commands.
Key Technical Specifications
- Model: MR-J4-100A
- Rated Output Power: 1 kW (1,000 W)
- Power Supply: 200–240 VAC single-phase or three-phase, 50/60 Hz
- Continuous Output Current: 6.0 A
- Maximum Output Current: 18.0 A (3× continuous peak)
- Compatible Servo Motors: HG-SR102, HG-SR1024, HG-KR13, HG-MR13 and equivalent
- Command Interface: Pulse train input (open-collector or differential RS-422A)
- Maximum Input Pulse Frequency: 4 Mpps (differential), 200 kpps (open-collector)
- Encoder Interface: Serial 22-bit absolute encoder (262,144 pulses/rev)
- Safety Function: STO (Safe Torque Off), IEC 61800-5-2 SIL2 / EN ISO 13849-1 PLe
- Regenerative Brake: Built-in, external MR-RB series resistor connectable
- Communication: USB (MR Configurator2), RS-422 (multi-axis cascade)
- Operating Temperature: 0°C to 55°C
- Dimensions (W × H × D): 55 mm × 170 mm × 165 mm
- Weight: Approx. 1.5 kg
Typical Industrial Applications
The MR-J4-100A at 1 kW is the standard servo amplifier specification for the most prevalent machine axis power requirement across industrial automation sectors. In CNC machining centre auxiliary axis applications — rotary indexing tables, tool changer axes, pallet shuttle drives — the MR-J4-100A provides the 1 kW continuous power for medium-load auxiliary positioning where the primary X, Y, Z feed axes use higher-power amplifiers and the auxiliary axis requires the same precision positioning capability in a smaller power frame. Three-axis Cartesian robot systems for pick-and-place, screw driving, and dispensing applications in electronic assembly machines commonly specify MR-J4-100A for the X and Y traverse axes where 1 kW provides adequate thrust for the arm mass at the programmed transit speeds, with a smaller MR-J4-70A or MR-J4-40A for the Z (vertical) axis. Packaging machine servo axes — pouch form stations, fill stations, seal jaw drives, and product transfer axes — widely use the MR-J4-100A for the primary station servo drives where 1 kW at 3,000 rpm provides the required torque at operating speeds up to 150 cycles per minute. In press brake and panel bending machine backstop positioning, the MR-J4-100A drives the backstop servo for accurate sheet metal reference positioning between bends — 1 kW provides adequate thrust for backstop masses of 20–50 kg at the required rapid positioning speeds. ASRS (Automated Storage and Retrieval System) mini-load crane X-axis horizontal traverse and Y-axis vertical lift axes at light payload ratings (up to 100 kg) commonly specify the MR-J4-100A as the primary drive axis — 1 kW continuous with 3× peak torque provides the acceleration required for productive crane cycle rates.
Replacement & Upgrade Notes
The MR-J4-100A is the direct current-generation replacement for the MR-J3-100A (pulse train, 1 kW, now discontinued) providing all the MR-J4-generation improvements: 22-bit encoder resolution (131,072 → 262,144 pulses/rev), built-in STO eliminating the external safety contactor, AVSC II dual notch filter, and improved auto-tuning. The MR-J4-100A accepts HC-SFS102, HC-KFS13, and HC-MFS13 J3-era motors in J4 motor compatibility mode (parameter PA22 = 1), enabling amplifier-only upgrade without motor replacement — the most common and cost-effective upgrade path for J3 servo axis replacement. Current-generation HG-SR102 and HG-KR13 motors provide the full 22-bit encoder benefit when replaced simultaneously with the amplifier, but the PA22 compatibility mode enables the motor replacement to be deferred to a separate maintenance event. Use MR Configurator2’s parameter conversion function to create an initial MR-J4-100A parameter set from the existing MR-J3-100A parameter file before the upgrade to minimise commissioning time. The MR-J4-100A’s 55 mm housing width and compatible mounting pattern match the MR-J3-100A exactly, enabling direct panel retrofit without panel modification or DIN rail repositioning.
Frequently Asked Questions
Q: What is the recommended pulse input connection type for the MR-J4-100A — open-collector or differential — and does it matter for a 2-metre cable from a QD75MH4?
A: For a 2-metre cable from a QD75MH4 differential output to the MR-J4-100A differential input, the differential RS-422A connection is strongly recommended — the QD75MH4’s differential output and the MR-J4-100A’s differential input reject common-mode electromagnetic interference from adjacent motor power cables, maintaining reliable pulse reception at 4 Mpps in noisy panel environments. Open-collector pulse connection at 2 metres and moderate frequencies (below 1 Mpps) is electrically viable but provides no noise rejection — even a brief noise-induced false pulse at 4 Mpps causes a position error that the servo system attempts to correct with a velocity spike. Always use differential connection when the host controller and MR-J4-100A both support it.
Q: Can the MR-J4-100A be used in torque control mode for a tension winding application without position feedback from the host controller?
A: Yes. The MR-J4-100A supports torque control mode via the analogue torque command input (±10 VDC on the CN1 VC terminal), where the motor torque is regulated proportional to the analogue command voltage rather than following a position command pulse train. In torque control mode, the position loop is disabled and the speed loop regulates torque — appropriate for winding, tension control, and press-fit operations where force rather than position is the primary control variable. Set the operating mode via parameter PA01 in MR Configurator2.
Q: Does the MR-J4-100A support the FANUC 0i-F CNC controller’s pulse output for a machine retrofit where the CNC is being retained?
A: Yes. The FANUC 0i-F (and other FANUC CNC controllers) provides differential RS-422A pulse output compatible with the MR-J4-100A’s differential pulse input. Connect the FANUC axis command output (PA+/PA-, PB+/PB-) to the MR-J4-100A’s pulse input differential terminals (PP/NP, PG/NG) with appropriate signal polarity verification. Configure the MR-J4-100A’s pulse input mode parameter to match the FANUC’s pulse format (A/B quadrature or pulse/direction) and verify the electronic gear ratio parameters match the axis’s commanded resolution. This configuration is commonly used for Mitsubishi servo motor retrofits on FANUC-controlled machine tools where the servo motors and amplifiers are replaced while retaining the FANUC CNC controller.
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