What Is SCADA? Supervisory Control Without Replacing the PLC
SCADA sits above PLCs and RTUs: it acquires field data, alarms operators, and issues supervisory commands across plants and remote assets—without replacing local deterministic control.

Optimizing heavy-duty industrial machinery performance, the Mitsubishi Electric FR-A840-55K-1 is a premium three-phase vector control variable frequency drive engineered for high-torque applications up to 55 kW. This high-performance FR-A800 series inverter features an integrated FM pulse terminal for precise monitoring and supports advanced Real Sensorless Vector Control (RSVC) to achieve exceptional speed and torque accuracy. Designed to integrate seamlessly into complex factory automation architectures, the unit provides reliable power conversion, extensive communications support, and robust energy-saving features to maximize process uptime.
| Parameter | Specification Value |
|---|---|
| Manufacturer | Mitsubishi Electric |
| Model Reference | FR-A840-55K-1 |
| Series | FR-A800 |
| Applicable Motor Capacity | 55 kW |
| Input Voltage Class | Three-Phase 400 V |
| Output Rated Voltage | Three-phase 380 to 500 V |
| Output Rated Current | 110 A |
| Output Capacity | 84 kVA |
| External Communications | RS-232 / RS-422 / RS-485 |
| Output Terminal Type | FM Term (Pulse Train Output) |
| Approvals & Standards | CE, UL, cUL, RoHS compliant |
| Dimensions (H x W x D) | 550 mm x 435 mm x 250 mm |
| Product Weight | 44 kg |
| Terminal Designation | Functional Assignment |
|---|---|
| R/L1, S/L2, T/L3 | Three-Phase AC Power Input Connection |
| U, V, W | Three-Phase AC Output to Motor |
| FM | Pulse Train Output Terminal for Monitoring |
| SD / SE | Contact Input / Sensor Common Ground Terminals |
| RJ-45 Connector | PU / RS-485 Communication Port |
The FR-A840-55K-1 serves as a direct functional replacement for legacy FR-A740-55K series drives. When replacing an older A700 series unit, parameter configurations can be transferred using Mitsubishi FR Configurator2 software. Note that although physical cabinet footprints are highly aligned, cooling fan clearances and terminal block configurations should be verified prior to structural integration.
To maintain optimal thermal performance under continuous duty in enclosed control cabinets, do not exceed an ambient temperature of 50 Celsius without applying appropriate derating guidelines. When running this unit with high carrier frequencies to eliminate motor audible noise, ensure that the output current rating is adjusted downward according to the manufacturer derating curves to avoid thermal over-current trips (E.THT / E.OC1).
For installations utilizing control cable runs longer than 30 meters to the FM pulse terminal, use shielded twisted-pair (STP) cabling. Ensure that the cable shield is grounded strictly at the drive-end ground point (PE terminal) to prevent industrial high-frequency noise from inducing signal distortion or false logic transitions. Always separate control signal wiring from high-power 400 V AC inputs and motor output cabling by a minimum clearance of 30 cm.
Isolate all electrical inputs before initiating installation or service on this equipment. High-voltage capacitors retain a lethal residual charge. Wait a minimum of 10 minutes after main power disconnection and measure the DC link voltage across terminals P/+ and N/- to verify it is below 45 V DC before touching terminal blocks or internal wiring.
Mount the drive vertically inside a dust-free, vibration-isolated cabinet. Ensure there is at least 100 mm of clearance above and below the drive housing for unhindered convective cooling airflow.
Connect the mains power input lines to terminals R/L1, S/L2, and T/L3, and connect the motor power cables to terminals U, V, and W. Tighten all terminal screws to the manufacturer-specified torque limits using a calibrated torque wrench.
Route control and pulse output signal lines through separate conduits to avoid electromagnetic interference. Ground the motor frame directly to the drive ground terminal, and ground the drive housing to the central protective ground bar of the facility.
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| Country of origin |
United States
|