CX5120-N031-0003 | BECKHOFF | Embedded PC Intel Atom E3815 RS485

Product Overview

The CX5120-N031-0003 (CX5120-N031-0003) is a fanless, compact Embedded PC designed for high-reliability industrial automation and serial communication tasks. Powered by the Intel Atom E3815 single-core processor (1.46 GHz), this controller offers a deterministic environment for PLC, Motion Control, and gateway applications. This specific model is factory-equipped with an integrated RS485 interface via a 9-pin D-sub socket, configured specifically as a drop point. It is widely utilized in large-scale building automation, smart grid monitoring, and complex factory networks where multiple devices must communicate over a shared serial bus without interfering with network impedance. Its magnesium die-cast housing provides excellent thermal dissipation and EMI protection, enabling stable operation in temperatures ranging from -25 to +60 Celsius.

Technical Configuration

The hardware architecture of the CX5120-N031-0003 is optimized for intermediate placement within a serial communication chain. The "N031" designation identifies the integrated RS485 port, which is hardware-configured as a drop point with internal termination off. This allows the unit to be bridged into an existing RS485 segment without the risk of signal reflection caused by multiple termination resistors. The interface also includes "echo" functionality, allowing the processor to monitor its own transmissions for bus contention detection. The device supports dual-bus technology, automatically identifying and controlling both EtherCAT (E-bus) and standard Bus Terminals (K-bus), ensuring maximum flexibility when interfacing with diverse I/O modules.

Technical Specifications

Technical FAQs

When should I choose the CX5120-N031-0003 over the termination-on model?

You should choose this model (N031-0003) if the Embedded PC will be located in the middle of an RS485 network. Since termination is OFF, it acts as a "drop point" and will not disrupt the signal impedance of the bus.

Does the single-core Intel Atom support TwinCAT 3?

Yes, the Intel Atom E3815 is fully compatible with TwinCAT 3. It is ideally suited for standard PLC logic, communication gateway tasks, and small-to-medium I/O configurations that do not require heavy multi-core processing.

Is the RS485 port isolated?

Yes, Beckhoff N031 interfaces typically provide electrical isolation from the internal PC electronics to protect the CPU from field-side transients and common-mode voltage differences on the serial line.

Engineering & Installation Guide

• Network Topology Placement: As this unit is configured as a drop point (Termination OFF), it must not be used as the first or last node in an RS485 segment unless you add an external 120 Ohm resistor. It is designed to be wired in a "daisy-chain" or "stub" configuration where other devices provide the line termination.

• Echo Signal Handling: With the echo function enabled, the software driver receives everything the unit transmits. Ensure your communication protocol (such as Modbus RTU) is configured to either ignore these echoes or use them for transmission verification to prevent "data collisions" in your PLC code.

• Heat Management: To ensure passive cooling performance, the CX5120-N031-0003 must be mounted vertically on the DIN rail. Avoid placing high-heat modules (such as power terminals or frequency inverters) directly below the PC's intake area.

• Wiring Precision: Use shielded twisted-pair (STP) cables for the RS485 connection. Connect the signal ground to Pin 5 of the D-sub connector to minimize the impact of ground potential shifts between different nodes on the network