NI PXI-8431/4 RS-485/RS-422 4-Channel Serial Interface

The NI PXI-8431/4 is a 4-channel RS-485/RS-422 serial interface module for the PXI platform, delivering reliable multi-point communication up to 3 Mbps. The module supports configurable baud rates from 57 baud to 3,000,000 baud with 0.01% accuracy on standard rates and 1% on non-standard rates, accommodating diverse serial device requirements. A high-performance DMA engine minimizes CPU overhead while enabling efficient data transfer, with support for multicore processors and hyperthreading. Selectable 4-wire and 2-wire transceiver modes support both full- and half-duplex operation. The module appears as standard COM ports in Windows and LabVIEW Real-Time environments, enabling compatibility with Visual Basic, Visual C++, Excel, LabVIEW, LabWindows/CVI, Measurement Studio, and Lookout without custom drivers.

– Technical Specifications

• 4 channels, RS-485 and RS-422 protocols
• Maximum data rate: 3 Mbps
• Baud rate range: 57 to 3,000,000 baud; accuracy 0.01% (standard) and 1% (non-standard)
• Transmit/receive FIFO: 128 Bytes per channel
• Power requirement: 5 VDC, 725 mA typical / 1.1 A maximum
• I/O connector: 10-position modular jack (RJ50)
• Dimensions: 16 cm × 10 cm, 3U form factor
• Operating temperature: 0 °C to 55 °C
• Maximum cable length: 1.2 km

– Key Features

• High-performance DMA engine reduces CPU utilization
• Interrupt sharing between ports eliminates resource conflicts
• Memory mapping for expanded communication endpoints
• Included 4× converter cables (10P10C to DB9 male)
• PXI Hybrid compatible architecture
• Supports both full- and half-duplex modes via selectable transceiver configuration

– Typical Applications

Remote sensor networks, industrial automation, distributed data acquisition, and legacy serial device integration requiring high-speed, multi-channel communication over extended distances.

– Compatibility & Integration

Full software compatibility with standard COM port interfaces and native support across multiple development environments enables integration into existing test systems without protocol modification.