USB Industrial Communication Interfaces

NI USB Industrial Communication Interfaces

USB Industrial Communication Interface Types

How to Select a USB Industrial Communication Interface

1. Identify the Required Protocol

Start with the connected device documentation. Determine whether the device communicates through CAN, CAN FD, LIN, FlexRay, RS-232, RS-422, RS-485, Ethernet or another supported interface.

Protocol names alone are not sufficient. Confirm the physical electrical standard, connector type, cable requirements, network topology and device communication role before selecting hardware.

2. Confirm the Electrical Physical Layer

Communication interfaces that appear similar can use different electrical signaling methods. RS-232, RS-422 and RS-485 are not interchangeable, and CAN, LIN and FlexRay each require their own compatible network interface.

Review logic voltage, common reference, cable length, shield connection, connector pinout and expected electrical environment. Long industrial cables and vehicle installations can introduce noise and ground-potential differences.

3. Determine Port Count and Bus Topology

Count the number of independent buses or serial ports needed. Each separate CAN network, serial device group or isolated subsystem may require its own communication channel.

For RS-485 networks, determine whether the installation uses two-wire or four-wire wiring, half-duplex or full-duplex communication, and multidrop connections. For vehicle networks, identify the network segments that must be logged, simulated or controlled simultaneously.

4. Verify Data Rate and Bus Loading

Confirm the required baud rate, message frequency, frame format and expected traffic load. The selected interface must support not only nominal communication speed but also the full monitoring, transmission, timestamping and logging workload.

CAN FD applications should verify classic CAN compatibility, arbitration-phase requirements and data-phase requirements. High bus traffic can also increase host-computer processing and file-storage demands during long recordings.

5. Evaluate Isolation and Grounding

Electrical isolation can help protect the computer and interface from ground-potential differences, noise and transient conditions. It is particularly important when connecting to industrial machinery, external power systems, long cable runs or vehicle electrical networks.

Isolation does not eliminate the need for correct grounding, shielding and cable routing. Confirm the complete installed wiring arrangement before connecting a USB interface to powered equipment.

6. Plan Termination and Cabling

CAN networks normally require termination at the two physical ends of the bus. Incorrect termination, poor cable selection, long stubs or unsuitable wiring can create intermittent communication faults.

Serial and Ethernet connections also require correct cable type, connector pinout, shielding and network configuration. Confirm whether the required cable, breakout accessory, terminal adapter or termination component is included in the system plan.

CAN, CAN FD, LIN and FlexRay Applications

CAN and CAN FD

CAN is widely used in vehicles, battery systems, industrial equipment and machinery. CAN FD extends classic CAN with larger payload capability and, in supported networks, a faster data phase. Confirm whether the application requires classic CAN only or CAN FD support.

Typical applications include passive bus monitoring, message logging, ECU validation, diagnostic development, hardware-in-the-loop testing and network simulation. Determine whether the interface must only receive data or also transmit and simulate network traffic.

LIN

LIN is commonly used for lower-cost automotive subnets and body-electronics functions. Applications should define the required master or slave behavior, schedule timing, network database and intended role of the connected PC.

FlexRay

FlexRay is a deterministic vehicle-network technology used in selected automotive applications. Confirm network topology, synchronization, channel requirements and software support before selecting an interface.

Serial and Industrial Equipment Communication

RS-232

RS-232 is commonly used for point-to-point communication with instruments, controllers and legacy devices. Confirm connector pinout, baud rate, handshake signals, cable length and device command protocol.

RS-422 and RS-485

RS-422 and RS-485 use differential signaling and are commonly selected for longer distances or electrically noisy industrial environments. RS-485 can support multidrop networks when the wiring, termination and communication direction are configured correctly.

Host Software Integration

Communication hardware is only one part of the system. Confirm the command set, message format, device protocol documentation and required software API. Legacy equipment may use manufacturer-specific commands that must be implemented by the application.

Software, Timestamping and Data Logging

Supported NI USB communication interfaces use the applicable NI driver and software stack for device recognition, configuration, transmission, reception, logging and analysis. Automotive network interfaces commonly use NI-XNET for supported CAN, LIN and FlexRay applications, while serial devices typically use the relevant NI serial or VISA software environment.

Network logs often need timestamps so communication traffic can be correlated with sensor data, digital events, test commands or fault conditions. Define whether the application needs approximate software timestamps, hardware timestamps or synchronized timing with another measurement system.

For long-duration logging, estimate message traffic, record format, storage capacity and host-computer workload. File writing, display updates and data decoding should not interfere with the communication task when continuous logging is required.

Typical Applications

• Automotive CAN, CAN FD, LIN and FlexRay logging
• ECU development, validation and diagnostic applications
• Battery-management-system monitoring and test
• Industrial PLC, drive and controller communication
• Serial instrument and legacy-equipment integration
• Vehicle-network simulation and hardware-in-the-loop testing
• Production-line communication monitoring
• Automated test-system instrument control
• Field diagnostics and maintenance data collection
• Combined network logging and sensor acquisition

USB Industrial Communication Interface Procurement Guide

FAQ

What is the difference between CAN and CAN FD?

CAN FD extends classic CAN with support for larger payloads and, in supported systems, a faster data phase. The interface, network nodes and application software must all support CAN FD when it is required.

Do I need termination for a CAN interface?

Yes. A CAN network normally requires termination at its two physical ends. Confirm the installed network topology and termination arrangement before connecting the interface.

Can an RS-485 device connect to an RS-232 interface?

No. RS-232 and RS-485 use different electrical signaling methods. Select an interface that matches the connected device’s actual communication standard.

Do I need an isolated USB communication interface?

Isolation is recommended when ground-potential differences, electrical noise, long cables or powered industrial equipment could affect the connection. Review the complete electrical environment before selection.

Can communication data be synchronized with analog measurements?

It can be correlated with measurement data, but achievable timing accuracy depends on the exact interface, drivers, timestamping method and system architecture. Confirm synchronization requirements before purchasing hardware.

Related NI Communication and Test Platforms

NI USB Industrial Communication Interfaces from PXISOURCE

PXISOURCE supports engineers and procurement teams with USB industrial communication interface selection, protocol and accessory matching, driver compatibility review and sourcing for new applications, spare inventory and legacy-system replacement.