The MR-J2S-100B is Mitsubishi Electric’s 1 kW MELSERVO-J2 Super series servo amplifier for 200 V single-phase or three-phase AC power supply with original SSCNET optical fibre network interface — a legacy servo amplifier from Mitsubishi’s second-generation MELSERVO Super platform, providing 1 kW continuous servo control via original SSCNET for HC-SFS102 and HC-KFS13 series servo motors in active multi-axis J2S SSCNET systems managed by Q172CPU or Q173CPU MELSEC-Q motion controllers. In stock at Atlantech Drives. Request your quote within 24-48 hours with worldwide shipping and 12-month warranty.
What Is the MR-J2S-100B?
The MR-J2S-100B is a MELSERVO-J2 Super series servo amplifier providing 1 kW (1,000 W) continuous output power via original SSCNET optical fibre — the 1 kW model in the MR-J2S-B SSCNET sub-series, compatible with Mitsubishi HC-SFS102, HC-KFS13, and equivalent 1 kW servo motors with the J2S-era serial encoder protocol. As a SSCNET-commanded amplifier, the MR-J2S-100B receives all position and speed commands from a Q172CPU or Q173CPU motion controller at 0.888 ms communication cycle time — no pulse train input is present, and the amplifier cannot operate without a connected J2S-era SSCNET motion controller. The 1 kW MR-J2S-100B is the most widely installed model in the MR-J2S-B sub-series, reflecting the high prevalence of 1 kW servo axes in the multi-axis J2S-era machine tool, robotic, and precision assembly equipment that was designed around the Q172CPU / MR-J2S SSCNET platform. The MR-J2S-100B’s 55 mm housing width is wider than the 40 mm MR-J2S-20B and MR-J2S-40B, reflecting the larger power components required for 1 kW output — this width difference should be noted when planning maintenance replacement or system documentation for J2S multi-axis panels. Like all MR-J2S-B amplifiers, the MR-J2S-100B communicates with the legacy MR Configurator software via RS-232C and does not include a built-in STO safety function.
Key Technical Specifications
- Model: MR-J2S-100B
- 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-era motors only)
- Command Interface: SSCNET optical fibre (original SSCNET, not SSCNET III)
- Communication Cycle: 0.888 ms
- 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)
- Compatible Motion Controllers: Q172CPU, Q173CPU
- Operating Temperature: 0°C to 55°C
- Dimensions (W × H × D): 55 mm × 150 mm × 138 mm
- Weight: Approx. 1.2 kg
Compatibility & System Integration
The MR-J2S-100B operates exclusively within original SSCNET chains managed by J2S-era Q172CPU or Q173CPU MELSEC-Q motion controllers. The original SSCNET network uses a different optical wavelength, connector type, and communication protocol than SSCNET III (MR-J3-B) and SSCNET III/H (MR-J4-B) — the three generations of Mitsubishi servo network are mutually incompatible, and MR-J2S-100B amplifiers cannot be mixed with MR-J3-B or MR-J4-B amplifiers on the same network chain. In multi-axis J2S SSCNET systems, the MR-J2S-100B can coexist in the same chain with other MR-J2S-B amplifiers of different power ratings (MR-J2S-20B, MR-J2S-40B, MR-J2S-200B, MR-J2S-350B) — all MR-J2S-B models use the same original SSCNET communication protocol and share the same 0.888 ms communication cycle. The MR-J2S-100B parameter access requires the legacy MR Configurator software — on modern Windows 10/11 PCs, MR Configurator requires a compatibility mode or virtual machine running an older Windows version (Windows XP or Windows 7) to install and operate reliably. The RS-232C physical connection requires a USB-to-RS-232C adapter on modern PCs without native serial ports — use an FTDI FT232R-based adapter for maximum software compatibility with legacy industrial software. Current-generation HG-SR102 and HG-KR13 servo motors (MR-J4 standard) are not compatible with the MR-J2S-100B’s encoder interface — only J2S-era HC-SFS102 and HC-KFS13 motors can be used as direct replacements for failed motors in MR-J2S-100B-based systems.
Maintenance Tips
The MR-J2S-100B at 1 kW is the most common J2S SSCNET amplifier in active field service, and the highest-priority preventive maintenance items are consistent with all MR-J2S-B models — cooling fan and DC bus capacitor condition. For MR-J2S-100B units above 12 years of service, schedule annual inspection of the cooling fan (listen for bearing noise, measure fan current draw) and visual inspection of the DC bus capacitors through the amplifier’s ventilation openings (check for bulging capacitor tops or electrolyte residue). Replace the cooling fan every 4–5 years as preventive maintenance — a seized cooling fan on a 1 kW amplifier causes AL.46 overtemperature shutdown within minutes of startup at full load. For the DC bus capacitors, proactive replacement at 12–15 years of service by a qualified servo amplifier repair specialist eliminates the risk of catastrophic capacitor failure that can damage the IGBT power module as secondary damage. Maintain a complete MR Configurator parameter backup file for every MR-J2S-100B in active service — connect MR Configurator via RS-232C annually and save the current parameter file to a dedicated maintenance archive, updating the archive whenever servo parameters are modified. This parameter backup is essential for rapid restoration after emergency replacement, as the replacement unit ships with factory default parameters that will not match the machine’s tuned servo gains, and re-tuning from scratch on a production machine adds significant commissioning time to the maintenance event. For the SSCNET optical cable connections (CN1A and CN1B), inspect the cable ends annually for dust contamination and optical connector cleanliness — the original SSCNET connectors are of an older design than SSCNET III connectors and may be more susceptible to contamination in dusty environments.
Frequently Asked Questions
Q: Can an MR-J2S-100B be used to replace a failed MR-J2S-100A in a machine that originally used pulse train control, by converting the axis to SSCNET control?
A: No. The MR-J2S-100B requires a Q172CPU or Q173CPU SSCNET motion controller to operate — it has no pulse train input and cannot be operated from a positioning module or CNC pulse output. Converting a pulse-train axis (MR-J2S-100A) to SSCNET (MR-J2S-100B) would require not only replacing the amplifier but also adding a Q172CPU or Q173CPU motion controller to the system, representing a major system architecture change rather than a maintenance replacement. The correct replacement for a failed MR-J2S-100A is another MR-J2S-100A (or an MR-J4-100A upgrade with simultaneous motor replacement).
Q: What is the maximum number of MR-J2S-100B amplifiers that can be connected to a single Q172CPU SSCNET chain?
A: The Q172CPU supports up to 8 SSCNET servo axes (8 amplifiers in the chain). A Q172CPU-based system with 8 MR-J2S-100B amplifiers at 1 kW each represents the maximum single-controller configuration for the J2S-era SSCNET system. For systems requiring more than 8 axes, the Q173CPU supports up to 32 axes. Both the Q172CPU and Q173CPU are discontinued from production and available only from aftermarket inventory.
Q: Is MR-J2S-100B failure more often caused by the amplifier or by the SSCNET connection hardware?
A: In J2S SSCNET systems above 12 years of age, the most common failure sequence is: first the cooling fan bearing (audible noise progressing to AL.46 overtemperature), then DC bus capacitor degradation (AL.30 overvoltage on deceleration or unstable operation on acceleration), and less commonly the SSCNET optical transceiver components (which manifest as AL.E1 or equivalent SSCNET communication alarms). Pure SSCNET optical transceiver failure is less common than thermal and capacitor failure modes — when SSCNET communication alarms occur, inspect the optical cables and connectors first before assuming the transceiver has failed.
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