CX5120-N031-0001 | BECKHOFF | Embedded PC Intel Atom E3815 RS485

Product Overview

The CX5120-N031-0001 (CX5120-N031-0001) is a robust, fanless Embedded PC designed for space-efficient industrial control and communication tasks. Powered by the Intel Atom E3815 single-core processor (1.46 GHz), this unit provides a highly deterministic environment for PLC and Motion Control applications via Beckhoff TwinCAT. This specific configuration features a factory-integrated RS485 serial interface via a 9-pin D-sub socket, optimized for the final node in a serial network. It is widely utilized in building automation, HVAC control, and manufacturing environments where reliable data exchange with legacy Modbus RTU or proprietary serial devices is required. Its magnesium die-cast housing ensures superior thermal management and EMI shielding, maintaining operation in temperatures ranging from -25 to +60 Celsius.

Technical Configuration

The hardware architecture of the CX5120-N031-0001 is tailored for serial bus master or terminal slave roles. The "N031" designation indicates the inclusion of an RS485 interface, which is hardware-configured as an end point. In this configuration, the internal 120 Ohm termination is set to on, eliminating the need for external termination resistors when this PC is at the physical start or end of the RS485 cable run. The interface also includes an "echo" function, which is often used in collision detection or for verifying transmitted data in specific half-duplex protocols. The device supports both EtherCAT (E-bus) and Bus Terminals (K-bus), providing seamless I/O expansion and high-speed synchronization with other modular components.

Technical Specifications

Technical FAQs

How is the "Termination On" setting beneficial for my installation?

Because this model is configured as an end point with termination ON, it provides the necessary impedance matching to prevent signal reflections on the RS485 line. You do not need to install an external 120 Ohm resistor on the D-sub connector, simplifying field wiring.

Can the CX5120-N031-0001 handle real-time Motion Control?

Yes. While it features a single-core Intel Atom, it is fully capable of managing point-to-point motion tasks and standard PLC logic within TwinCAT 3, provided the task cycle times are balanced with the processor's performance overhead.

What is the purpose of the "Echo" configuration on the RS485 port?

With echo enabled, the receiver remains active during transmission, allowing the PC to "hear" its own sent data. This is used by certain communication protocols to detect bus contention or to verify that the transceiver is functioning correctly before waiting for a slave response.

Engineering & Installation Guide

• RS485 Network Placement: Since this specific part number is configured with internal termination ON, it must be placed at one of the two extreme ends of the RS485 bus. Placing this unit in the middle of a multi-drop network will cause incorrect impedance loading and likely lead to communication errors or data corruption.

• Cable Selection and Grounding: Use high-quality shielded twisted-pair cable specifically rated for RS485 (120 Ohm characteristic impedance). Ensure the shield is grounded at the CX5120 side to Pin 5 (GND) or via the D-sub housing to prevent electromagnetic interference from distorting the serial frames.

• Thermal Orientation: To ensure the longevity of the Intel Atom E3815, mount the unit vertically on the DIN rail. This allows the cooling fins on the magnesium housing to facilitate natural convection. Ensure a 30 mm vertical gap from other heat-generating components.

• I/O Integration: The unit automatically detects whether an EtherCAT (ELxxxx) or Bus Terminal (KLxxxx) segment is attached. However, do not mix E-bus and K-bus terminals in the same physical strand without a specialized conversion terminal.