The NI PXI-8431/8 is an eight-port serial interface module for RS-485 and RS-422 communication within PXI systems. Designed for industrial automation, embedded systems, and data acquisition, it delivers high-speed serial connectivity with configurable transceiver modes, DMA support, and direct COM port emulation. The module integrates into PXI Hybrid systems and supports both real-time and Windows operating environments.
Technical Specifications
• Serial Standards: RS-485/RS-422
• Number of Ports: 8 independent channels
• Transceiver Modes: 2-wire (half-duplex) and 4-wire (full-duplex)
• Maximum Baud Rate: 3 Mbps
• Baud Rate Accuracy: 0.01% for standard rates; 1% for non-standard rates
• Configurable Data Bits: 5, 7, or 8 bits per packet
• Maximum Cable Length: 4000 feet (1.2 km) for RS-485
• Maximum Devices per Port: 31–32 (RS-485)
• I/O FIFO Buffer: 128 B
• I/O Connector: 68-pin VHDCI
• Supplied Cable: 68-pin VHDCI to 8 DB-9 male adapter (part 197546-01)
• Power Supply: +5 VDC internal
• Typical Current: 925 mA; Maximum: 1.4 A
• Operating Temperature: 0 °C to 55 °C
• Dimensions: 100 × 160 mm
• Weight: 137 g
– Key Features
• Direct Memory Access (DMA) minimizes CPU overhead during high-throughput transfers
• COM port emulation presents all 8 ports as standard serial interfaces
• Hardware flow control via RTS/CTS handshake lines
• Interrupt sharing between ports reduces PXI bus contention
• Full multithreading and multiprocessor support with hyperthreading compatibility
• Any baud rate from 2 baud up to 3 Mbps
– Compatibility & Integration
• PXI Hybrid compatible architecture
• LabVIEW RT support confirmed
• MXI compatible for remote chassis operation
• Supports Windows and real-time operating systems
