Beckhoff CX2072-N031 Basic CPU Module with RS485 Interface

Product Overview

The CX2072-N031 (CX2072 N031) is a high-performance basic CPU module within the Beckhoff CX2000 industrial PC series, specifically equipped with a factory-integrated RS485 interface. Designed for demanding multi-core processing tasks in large-scale plant automation, power generation, and high-speed manufacturing lines, the CX2072-N031 acts as the centralized intelligence for complex control architectures. The inclusion of the N031 option provides a dedicated 9-pin D-sub connection for serial communication, facilitating seamless integration with legacy field devices, power meters, or specialized sensors. This module is engineered to maximize system uptime by consolidating high-compute power with reliable, hardware-level serial connectivity in a rugged, DIN rail-mountable form factor.

Technical Configuration

The CX2072-N031 is defined by its integrated serial communication sub-module, which is configured for point-to-point or multi-drop RS485 topologies. Unlike standard serial ports, the N031 variant is pre-configured as an end point with internal termination enabled, ensuring signal stability by preventing reflections across the communication line. The "without echo" setting optimizes data throughput by ensuring the transmitter does not receive its own signals, which is critical for deterministic half-duplex communication. The module utilizes the high-speed internal PCI Express bus to interface the CPU with the serial hardware, ensuring minimal latency between logic execution and fieldbus data transmission.

Technical Specifications

Technical FAQs

Can the RS485 interface on the CX2072-N031 be used for Modbus RTU communication?

Yes. The integrated RS485 interface is fully compatible with Modbus RTU protocols. Through TwinCAT software, users can configure the baud rate, parity, and stop bits to match the requirements of the slave devices on the network.

Is it possible to disable the internal termination if this module is not at the end of the bus?

The N031 variant is hardware-configured with termination "ON" as an end-point device. If your network topology requires the CPU to be located in the middle of a bus segment, you must ensure no other external termination is applied at that node, or consult Beckhoff documentation for specific hardware bridge adjustments.

What is the maximum data rate supported by the D-sub RS485 interface?

While the hardware can support high-speed serial transmission, the typical operational speed for the N031 interface in industrial environments is up to 115.2 kbaud, ensuring reliable data integrity over standard distances.

Engineering & Installation Guide

• Bus Termination Strategy: Since the CX2072-N031 is configured as an end point with termination active, it should ideally be placed at one physical end of the RS485 segment. If multiple devices are connected, ensure the device at the opposite end of the cable also has a 120 Ohm termination resistor enabled to maintain impedance matching.

• D-sub Pin Assignment: When wiring the 9-pin D-sub connector, prioritize using high-quality shielded cables. For RS485, typically Pin 3 (Data B/+) and Pin 8 (Data A/-) are utilized. Always connect the cable shield to the D-sub metal housing to provide a continuous ground path for EMI protection.

• Thermal Management: The CX2072 series generates significant heat during high-load processing. Ensure a minimum clearance of 30 mm above and below the module to allow for natural convection. Failure to provide adequate airflow can lead to thermal throttling of the CPU, impacting real-time control performance.