The NI PCIe-8431/2 is a 2-channel serial interface card for RS485 and RS422 communication over PCI Express. It delivers data rates up to 3 Mbps with selectable 4-wire full-duplex or 2-wire half-duplex transceiver modes, supporting baud rates from 2 baud to 3000 kbaud with 1.3% accuracy. The card features high-performance DMA transfers, 128-byte FIFO buffers, multiprocessor support, and multithreading capabilities for efficient system resource utilization. Dual serial connectors—one DB-9 male for RS-422/RS-485 devices and one 68-pin VHDCI I/O connector—accommodate diverse field configurations. Powered directly from the PCIe slot at 325 mA typical draw, the card integrates as standard COM ports in Windows and LabVIEW Real-Time OS environments, enabling deployment with legacy serial software without modification. NI-VISA and NI-Serial drivers are provided at no cost.
Technical Specifications
• Data Rate: Up to 3 Mbps
• Baud Rate Range: 2 baud to 3000 kbaud, all rates within 1.3% accuracy
• Serial Protocols: RS485, RS422
• Transceiver Modes: Selectable 4-wire (full-duplex) and 2-wire (half-duplex)
• FIFO Buffer: 128 bytes transmit and receive
• Host Interface: PCI Express
• Serial Connectors: DB-9 male (RS-422/RS-485), 68-pin VHDCI I/O
• Power: 325 mA typical at +5 VDC from PCIe slot
• Operating Temperature: 0 to 55 °C
• Storage Temperature: –20 to 70 °C
• Humidity (Operating): 10 to 90% RH non-condensing
• Humidity (Storage): 5 to 95% RH non-condensing
• Dimensions: 4.38 × 6.9 inches (11.12 × 17.53 cm)
• Weight: 0.20 lb
– Key Features
• High-performance DMA transfers minimize CPU overhead
• Multiprocessor and multithreading support for parallel operations
• Standard COM port presentation for legacy software compatibility
• Supports nonstandard baud rates with precision timing
• Dual-mode transceiver operation for both full and half-duplex networks
– Typical Applications
• Industrial automation serial networks
• Data acquisition systems
• Embedded systems integration
• Multi-device sensor and actuator control
– Compatibility & Integration
• Operating Systems: Windows, LabVIEW Real-Time OS
• Drivers: Free NI-VISA API and NI-Serial drivers
• Safety Compliance: IEC 61010-1, EN 61010-1, UL 61010-1, CSA 61010-1
