The MR-J2S-100A is Mitsubishi Electric’s 1 kW MELSERVO-J2 Super series servo amplifier for 200 V single-phase or three-phase AC power supply with pulse train position command input — a legacy servo amplifier from Mitsubishi’s second-generation MELSERVO Super platform, providing 1 kW continuous servo control at 6 A for HC-SFS102 and HC-KFS13 series servo motors in active J2S-based servo systems requiring direct maintenance replacement. The MR-J2S-100A is available through Atlantech Drives — quote within 24-48 hours, worldwide express shipping, 12-month warranty.
What Is the MR-J2S-100A?
The MR-J2S-100A is a MELSERVO-J2 Super series servo amplifier providing 1 kW (1,000 W) continuous output power for Mitsubishi HC-SFS102, HC-KFS13, and equivalent 1 kW servo motors with the J2S-era serial encoder. As the 1 kW model in the MR-J2S-A pulse train sub-series, the MR-J2S-100A is five times the continuous power of the MR-J2S-20A, reflecting the broader range of machine axes that the 1 kW class addresses — from CNC machining centre feed drives and rotary indexing tables to robotic arm axes and packaging machine servo drives in the J2S equipment generation. The MR-J2S-100A accepts position command pulses from a host controller via open-collector or differential pulse input, and implements the J2S three-loop servo control architecture with approximately 1.5 kHz current loop bandwidth. The RS-232C communication port (9-pin D-Sub) connects to the legacy MR Configurator software for parameter configuration and servo tuning — USB connection via MR Configurator2 support should be verified for the specific MR-J2S-100A firmware version before relying on MR Configurator2 for J2S maintenance programming. Like all MR-J2S-A amplifiers, the MR-J2S-100A does not include a built-in STO safety function.
Key Technical Specifications
- Model: MR-J2S-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: HC-SFS102, HC-KFS13 (J2S/J3-era motors)
- Command Interface: Pulse train input (open-collector or differential)
- Maximum Input Pulse Frequency: 500 kpps (differential), 200 kpps (open-collector)
- Encoder Interface: Serial encoder (J2S-era HC motor encoder protocol)
- Safety Function: None built-in
- Regenerative Brake: Built-in, external regenerative resistor connectable
- Communication: RS-232C (MR Configurator legacy software)
- Operating Temperature: 0°C to 55°C
- Dimensions (W × H × D): 55 mm × 150 mm × 138 mm
- Weight: Approx. 1.2 kg
Typical Industrial Applications
The MR-J2S-100A is found in active service in a wide range of medium-duty servo axis applications from the MELSERVO-J2 Super era (approximately 1999–2008), representing the most common power level in the J2S installed base. In CNC machining centres with J2S-era servo systems, the MR-J2S-100A typically drives the Z-axis (vertical spindle head) and the smaller linear axes where 1 kW provides adequate thrust. Rotary indexing tables with 200–400 mm dial diameters commonly used the MR-J2S-100A as the primary servo drive, positioning the table between stations via the pulse train command from a PLC positioning module or CNC controller. In electronic assembly equipment — chip shooters, screen printers, and dispensing machines — the MR-J2S-100A drives the X and Y axes of Cartesian gantry systems, where 1 kW is more than adequate for the light head masses at the moderate speeds typical of these machines. Packaging machinery from the J2S era uses the MR-J2S-100A for fill station, seal station, and cut station axes in flow wrap and sachet packaging machines, where the combination of moderate axis mass, moderate speed, and high cycle frequency suits the 1 kW J2S platform. In currently active service, MR-J2S-100A maintenance replacement requests typically originate from machines in food and beverage, automotive components, and electronic assembly facilities where the machine itself continues to perform acceptably but individual servo amplifier failures require replacement parts that are no longer in standard distribution channels.
Troubleshooting Guide
For MR-J2S-100A amplifiers generating AL.16 (encoder error) or similar encoder communication alarms, the diagnostic approach differs from MR-J3 and MR-J4 systems due to the J2S encoder protocol specifics. First verify the encoder cable connection at both the amplifier’s CN2 connector and the motor-side connector — J2S encoder cables use a 15-pin D-Sub connector at the amplifier end, physically distinct from the MR-J3’s and MR-J4’s circular connectors. A corroded or partially seated 15-pin D-Sub at the amplifier end is the most common physical cause of J2S encoder errors in older installations. If the encoder cable appears intact and fully seated, measure the 5 VDC supply at the encoder cable’s power pins using a multimeter at the motor-side connector — a degraded encoder cable with increased conductor resistance causes the 5 VDC encoder supply to sag below the encoder’s minimum operating voltage, causing sporadic encoder communication errors that are indistinguishable from an encoder hardware failure. For MR-J2S-100A amplifiers generating AL.50 (overload) in normally loaded applications, the most likely cause at this age is DC bus capacitor degradation — capacitors with increased ESR reduce the DC bus voltage hold-up during motor acceleration, causing the thermal model to accumulate faster and trip the overload alarm at load levels that the original capacitors would have handled without alarm. Capacitor degradation is confirmed by AL.50 occurring on acceleration rather than during sustained high-speed operation, and by measuring DC bus ripple voltage during a representative acceleration cycle using an oscilloscope connected across the DC bus capacitors.
Frequently Asked Questions
Q: Can the MR-J2S-100A be upgraded to MR-J4-100A without replacing the servo motor?
A: No. Unlike MR-J3-to-MR-J4 upgrades where motor compatibility mode enables amplifier-only replacement, the MR-J2S-to-MR-J4 upgrade requires simultaneous replacement of both the amplifier and the servo motor. The J2S-era HC-SFS102 and HC-KFS13 motors use a J2S-specific encoder protocol that no MR-J4 amplifier can read — even in compatibility mode, the MR-J4-100A cannot interpret J2S encoder signals. A complete J2S-to-J4 upgrade requires: MR-J2S-100A → MR-J4-100A (amplifier), HC-SFS102 → HG-SR102 or equivalent (motor), J2S encoder cable → MR-J4 encoder cable, and complete servo re-tuning.
Q: What is the service life of the MR-J2S-100A’s DC bus capacitors, and how can degradation be detected before failure?
A: The MR-J2S-100A’s electrolytic DC bus capacitors are rated for approximately 10 years at 40°C ambient. Units in service beyond 12–15 years should be considered at high risk of capacitor failure. Early detection indicators include: AL.50 overload alarms occurring at load levels previously handled without alarm; increased DC bus ripple measured with an oscilloscope during acceleration (ripple above 30 V peak-to-peak at full load indicates significant capacitor degradation); and visible physical changes to the capacitor — bulging tops or electrolyte residue visible through the amplifier’s ventilation openings. Annual inspection for physical capacitor condition is recommended for MR-J2S-100A units above 10 years of age.
Q: Is the MR-J2S-100A physically interchangeable with the MR-J3-100A in terms of panel mounting?
A: The MR-J2S-100A (55 mm width, 150 mm height) and the MR-J3-100A (55 mm width, 170 mm height) share the same 55 mm housing width but differ in height — the MR-J3 is 20 mm taller. The mounting hole pattern differs between generations, so direct mechanical substitution in an existing panel cutout is not possible without modification. The DIN rail mounting depth also differs slightly between J2S and J3 generations. A complete panel modification is typically required when upgrading from MR-J2S-100A to MR-J3-100A or MR-J4-100A.
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