Product Overview

The ABB NDCU-21C 64009095B Drive Control Unit is a drive control assembly used in ABB ACS 600 industrial frequency converter systems. It provides the electronic control interface between the drive application, motor control functions, inverter power stage, and external control equipment.

The NDCU-21C consists of two main electronic boards: the NAMC-21C Application and Motor Controller Board and the NIOC-01C Input/Output Board. These boards are assembled inside a protective enclosure, forming a centralized control unit for compatible ABB drive installations.

The NAMC-21C handles application-related processing and motor control operations, while the NIOC-01C provides analog inputs, analog outputs, digital inputs, and relay output connections. Together, they allow the drive controller to receive external reference signals, process operating information, and exchange control signals with associated equipment.

The unit supports several communication interfaces, including DDCS optical communication channels, PPCS inverter communication, and RS-485 connections. These interfaces allow the NDCU-21C to communicate with inverter modules, external controllers, control panels, and other drive system components.

In an industrial production line, for example, the NDCU-21C can coordinate the operation of an ABB drive by processing control references and feedback signals while communicating with the inverter section. This arrangement supports motor speed regulation, drive monitoring, and coordinated operation within larger converter systems.

The NDCU-21C is also used in compatible ABB IGBT supply unit configurations. Its application depends on the installed control program and the communication arrangement of the converter system.

An important purchasing consideration is that the hardware-only NDCU-21C does not automatically include application software. The required software must be selected according to the intended drive application, such as standard drive control, master-follower operation, or supply unit control.

For maintenance engineers replacing an existing control assembly, the complete ordering identification, board configuration, optical communication requirements, and application software version should be checked before installation.

Technical Specifications

Product Features

• Dual-Board Architecture: Combines NAMC-21C and NIOC-01C boards within one drive control assembly.
• Application and Motor Control: Uses the NAMC-21C board for drive application processing and motor control functions.
• Integrated I/O Interface: The NIOC-01C provides three analog inputs, two analog outputs, six digital inputs, and three relay outputs.
• DDCS Optical Communication: Supports communication between the drive controller and associated optical communication devices.
• PPCS Inverter Interface: Provides a communication link with the inverter power section.
• RS-485 Connectivity: Supports serial communication with compatible external control equipment.
• Coated Circuit Boards: Uses coated NAMC and NIOC boards for the corresponding industrial drive configuration.
• External Control Integration: Supports connection to control panels, application controllers, and associated drive equipment.
• Separate Software Configuration: Allows the required application program to be selected according to the intended drive function.
• ACS 600 Integration: Supports compatible ABB ACS 600 converter architectures.

Working Principle

The ABB NDCU-21C operates as the central electronic control assembly in a compatible ABB drive system. Its two main boards divide application processing and signal interface functions, allowing the converter to coordinate motor or supply-unit operation.

Application and Motor Control Processing

The NAMC-21C board performs the application and motor control processing functions.

It processes control references, operating information, and feedback signals according to the installed application program. These calculations determine the control commands required by the associated drive system.

The specific control functions depend on the software installed on the NAMC board.

Analog and Digital Signal Processing

The NIOC-01C board provides the external signal interfaces required by the drive control unit.

Its analog inputs receive external reference or measurement signals, while the analog outputs provide corresponding signal outputs. Digital inputs allow the controller to receive operating commands and status information from external equipment.

Three relay outputs provide switching interfaces for configured control and status functions.

Communication with the Inverter

The NDCU-21C communicates with the inverter section through its PPCS interface.

This communication path allows the control unit to exchange information with the inverter electronics and coordinate the operation of the power conversion stage.

DDCS Optical Communication

The unit includes multiple DDCS communication channels for connections with compatible drive components and external controllers.

These channels support communication with devices such as application controllers, I/O equipment, and other drive control components.

The NDCU-21C uses 10 MBd optical transmitter and receiver components on DDCS channel CH0. This distinction is important when connecting an overriding controller because the optical components at both ends of the link must be compatible.

RS-485 Communication

The RS-485 interfaces support serial communication with compatible control equipment.

Depending on the drive configuration, these connections can be used for control panel communication and other system-level communication requirements.

Drive System Coordination

After processing the application signals and receiving the necessary feedback information, the NAMC board coordinates the drive operation through the relevant communication interfaces.

The inverter power section performs the actual electrical power conversion, while the NDCU-21C manages the associated electronic control functions.

Role in ABB ACS 600 Drive Control Architecture

The NDCU-21C serves as the central control assembly within compatible ABB ACS 600 drive and converter configurations. It connects application processing, external I/O, inverter communication, and supervisory control interfaces.

A simplified system arrangement is:

External Reference Signals → NIOC-01C I/O Board → NAMC-21C Controller → PPCS Interface → Inverter Power Section → AC Motor

In a multidrive installation, the NDCU-21C can coordinate the operation of its associated converter section while exchanging information with other system components.

The exact system arrangement depends on the installed application software, converter type, and communication configuration.

Industrial Applications

Installation and Maintenance

1. Verify the Product Identification: Confirm the NDCU-21C model and 64009095B ordering identification before replacement.
2. Check Board Configuration: Verify that the replacement includes the correct NAMC-21C and NIOC-01C boards.
3. Confirm Drive Compatibility: Check the host ABB ACS 600 converter model and its original control architecture.
4. Verify Application Software: Identify the required application program and confirm that the correct software is available for the replacement controller.
5. Check Optical Communication: Verify the DDCS optical interface requirements, particularly the 10 MBd components on channel CH0.
6. Record Existing Connections: Document the fiber-optic cables, I/O wiring, RS-485 connections, and inverter communication connections.
7. Isolate the Drive System: Disconnect the equipment from the power supply and follow the manufacturer’s DC-link discharge and electrical safety procedures.
8. Apply ESD Protection: Use appropriate electrostatic discharge protection when handling the NAMC and NIOC boards.
9. Inspect Connectors and Boards: Check the optical connectors, terminal blocks, board surfaces, and internal connections for damage or contamination.
10. Install the Replacement Assembly: Position and secure the NDCU-21C according to the applicable ABB installation instructions.
11. Verify Software and Communication: Confirm the application program, DDCS links, PPCS communication, RS-485 connections, and external I/O signals.
12. Perform Functional Testing: Check controller operation, drive communication, signal processing, and associated converter functions before returning the system to service.

Compatible System Components

Recommended Related Models

Key Advantages

• Combines application processing and I/O functions in one control assembly.
• Provides dedicated NAMC-21C motor control and application processing hardware.
• Supports multiple analog and digital signal connections.
• Includes DDCS optical and PPCS inverter communication interfaces.
• Supports RS-485 communication with compatible external equipment.
• Integrates with compatible ABB ACS 600 drive architectures.
• Allows application software selection according to the intended converter function.
• Supports coordinated operation of compatible inverter and supply-unit systems.

Technical FAQs

What boards are included in the ABB NDCU-21C 64009095B?

The NDCU-21C control assembly consists of a NAMC-21C Application and Motor Controller Board and a NIOC-01C Input/Output Board. Both boards are installed inside the control unit enclosure.

Is application software included with the NDCU-21C hardware?

Not necessarily. The hardware-only version does not automatically include application software. The required program must be selected separately according to the intended application, such as standard drive control, master-follower operation, or IGBT supply-unit control.

What is the difference between the ABB NDCU-21C and NDCU-22C?

Both units use the NDCU-2x architecture with NAMC and NIOC boards. One important difference is the optical component specification on DDCS channel CH0. The NDCU-21C uses a 10 MBd transmitter and receiver, whereas the NDCU-22C uses 5 MBd components. The correct version must match the connected optical communication equipment.

Can the NDCU-21C control an ABB IGBT supply unit?

Yes. The NDCU-21C is used in compatible ABB IGBT supply-unit control configurations. The appropriate supply-unit application program and communication arrangement must be selected for the specific converter installation.