ABB RDCU-02C Drive Control Unit

General Description

The RDCU-02C is the central control board for ABB’s ACS800 family of AC drives, including single drives and multidrive modules. It houses the microprocessor running the DTC algorithm, which provides accurate torque and speed control without a tachometer. The unit also manages all I/O, fieldbus communication, and protection functions. It is typically mounted in the drive cabinet and connected to power modules via fiber optic cables.

Key Features

• Direct Torque Control (DTC): Provides precise motor control with torque response < 5 ms, and speed accuracy of ±0.01% without encoder.

• Processor: 32-bit RISC, 50 MHz, dedicated to real-time control tasks.

• Built-in I/O: 6 digital inputs (24 V DC), 2 analog inputs (current/voltage selectable), 2 relay outputs, and 1 analog output (0-20 mA).

• Fiber Optic Links: Two channels (Tx/Rx) for communication with power modules (IGBT drivers, measurements).

• Fieldbus Adapter Slot: Accepts optional modules for PROFIBUS DP, DeviceNet, CANopen, Modbus, and Ethernet.

• Encoder Interface: Supports incremental encoder (TTL/HTL) via optional pulse encoder interface module.

• Memory Unit: Removable memory unit (MU) stores parameter sets and enables quick commissioning.

Technical Specifications

• Power Supply: 24 V DC ±20%, 0.5 A (supplied from drive power supply or external).

• Digital Inputs: 24 V DC, common positive/negative, programmable functions.

• Analog Inputs: 2 differential, 0(4)-20 mA (Ri=250 Ω) or 0-10 V (Ri=200 kΩ).

• Relay Outputs: 2 changeover relays, 250 V AC / 30 V DC, 2 A.

• Analog Output: 0-20 mA, load max 500 Ω.

• Operating Temperature: -10°C to +55°C.

• Dimensions: 260 x 170 x 45 mm (H x W x D).

• Weight: 0.8 kg.

Functional Description

The RDCU-02C acquires current and voltage signals from the power stage, computes motor flux and torque, and generates optimal switching commands. It also executes application programs such as PID control, sequence logic, and positioning tasks. The unit includes comprehensive protection features: overcurrent, overvoltage, undervoltage, motor stall, and thermal overload. Diagnostic LEDs indicate status: power, fault, and communication activity.

Applications

• Pumps, fans, compressors.

• Conveyors, extruders, mixers.

• Cranes, hoists, winches.

• Test stands, dynamometers.

• Marine propulsion and offshore drives.

Configuration and Tools

Drive parameters are set using ABB’s DriveWindow PC tool or the optional control panel (CDP-312). The RDCU-02C supports adaptive programming for custom logic. The memory unit (MU) allows easy transfer of settings between drives, reducing commissioning time.

Compliance

• CE, UL, cUL, and EAC marked.

• Designed to IEC/EN 61800-5-1, IEC/EN 61800-3 (EMC).

• Marine type approvals available (ABS, DNV, GL, LR).

Note: This document provides technical information; for detailed integration, refer to the ACS800 hardware manual.