Metso Valmet A413016 NCU2 – Network Control Unit (Model 17)

The Metso Valmet Automation A413016 NCU2 (Network Control Unit) is a powerful communication and control module designed for the Valmet DNA and Metso distributed control systems. Identified by model 17 and revision 09, this board acts as a network node that manages fieldbus communication, routes data between different network segments, and provides local processing capabilities for distributed automation tasks. It is commonly deployed in paper mills, chemical plants, and power generation facilities to ensure seamless data exchange between controllers, I/O stations, and operator workstations.

Processor and Memory Architecture

The NCU2 Model 17 is equipped with a 32‑bit ARM Cortex‑A8 processor running at 800 MHz, with a dedicated network coprocessor for handling communication protocols. It includes 512 MB of DDR3 RAM and 256 MB of NAND flash memory for firmware and configuration storage. The board also features a removable microSD card slot for data logging, firmware backup, and configuration transfer. The revision 09 improves the memory bandwidth and adds error‑correcting code (ECC) protection for critical data structures.

Communication Interfaces and Protocol Support

The NCU2 provides a comprehensive set of networking interfaces: two Gigabit Ethernet ports (redundant, with integrated switch), two RS‑485 ports for Modbus RTU or Profibus DP, one CAN‑bus interface for I/O expansion, and a fiber‑optic port for high‑speed backbone connection. It supports a wide range of industrial protocols, including PROFINET, EtherNet/IP, Modbus TCP, OPC UA, and the Valmet proprietary protocol. The Model 17 adds support for MQTT and REST API for IIoT and cloud integration, enabling data exchange with enterprise systems.

Data Routing and Network Management

The unit functions as a network router and gateway, capable of bridging different communication networks and translating between protocols. It maintains a routing table with up to 1024 entries and supports VLAN tagging for network segmentation. The NCU2 also includes a built‑in network diagnostic tool that monitors traffic, detects errors, and provides statistics on each interface. The revision 09 introduces improved Quality of Service (QoS) settings, ensuring that time‑critical control data is prioritized over less urgent traffic.

Local Control and Logic Execution

In addition to its communication functions, the NCU2 can execute local control logic and sequence programs using the IEC 61131‑3 programming languages. It can run up to 16 independent tasks with different priority levels, making it suitable for applications such as pump sequencing, valve interlocking, and alarm handling. The local execution capability offloads the main CPU and reduces network traffic, improving overall system performance.

Diagnostic and Monitoring Features

The NCU2 includes comprehensive self‑diagnostic features: monitoring of internal temperature, supply voltage, memory integrity, and network link status. A hardware watchdog resets the processor in case of a software fault. The front panel features a graphical OLED display (128 x 64 pixels) that shows network statistics, error codes, and system status. The module also supports remote diagnostics via the web interface, allowing maintenance personnel to troubleshoot issues from any location.

Hardware Design and Mounting

The NCU2 is housed in a rugged metal enclosure (160 mm x 120 mm x 60 mm) designed for DIN rail (TS35) mounting. It requires a 24 V DC supply (18‑32 V) with a maximum current of 1 A. All field connections are made via screw‑type terminal blocks and RJ45 connectors. The front panel features LED indicators for power, network activity, and module health. The unit is IP20 rated and includes a removable terminal cover for safety.

Environmental and Compliance

Operating temperature: ‑20 °C to +60 °C; storage: ‑40 °C to +85 °C; humidity: 5‑95 % non‑condensing. The unit is conformal coated and meets EN 61000‑6‑2/‑4 standards. It carries CE and UL certifications. Vibration tolerance is 5 g (10‑500 Hz) and shock 30 g. MTBF is estimated at 1,000,000 hours.

Installation and Commissioning

Mount the NCU2 on the DIN rail and connect the power supply. Connect the network cables and fieldbus wiring to the appropriate interfaces. Use the Valmet Engineering Tool to configure the network parameters, protocol settings, and routing table. The unit can also be configured via a built‑in web interface for basic setup. After configuration, verify the network connectivity and data exchange with the controller and I/O stations.

Applications

The NCU2 is deployed as a network gateway between the control network and fieldbus networks, as a data concentrator for remote I/O panels, and as a communication interface for third‑party devices. It is widely used in paper machine drive systems, boiler control networks, and chemical plant distributed control architectures.

Maintenance and Firmware Updates

Routine maintenance includes cleaning the housing, checking the ventilation slots, and verifying the LED indicators. Firmware updates are performed via the Ethernet port using a secure upload procedure. The microSD card can be used to backup and restore configuration settings, simplifying replacement in case of failure.

Conclusion

The Metso Valmet A413016 NCU2 Model 17 offers a powerful, reliable, and versatile network control solution for distributed automation systems. Its comprehensive communication capabilities, local processing power, and robust construction make it a critical component for modern industrial networks.