Model Nomenclature

PXIe: PXI Express (high‑speed PCIe‑based PXI bus).

8431: NI high‑performance serial series; 31 = RS‑422/RS‑485 optimized.

/8: 8 ports (single‑slot high density).

781473‑01: NI factory part number.

Siblings: PXI‑8431/4 (4‑port), PXI‑8430 (RS‑232)

Technical Specifications

• Form Factor: 3U, single‑slot PXI Express.

• Ports: 8 × software‑selectable RS‑422 (full‑duplex) / RS‑485 (half‑duplex).

• Baud Rate: Up to 3 Mb/s; supports standard and custom rates (±1% accuracy).

• FIFOs: 128‑byte transmit / 128‑byte receive per port.

• Isolation: Non‑isolated (for isolated version, use PXI‑8433).

• Connector: Front‑panel 68‑pin VHDCI female; includes 68VHDCI‑DB9M cable (197546‑01).

• Signaling: Differential; RS‑422 (4‑wire, full‑duplex); RS‑485 (2‑wire, half‑duplex).

• Flow Control: Hardware (RTS/CTS, DTR/DSR); software (XON/XOFF).

• Data Transfer: DMA‑capable; minimal CPU usage; multithreading/multiprocessor support.

• Power: 5 V DC from PXIe backplane; typical ~1.5 A.

• Environment: Operating 0–55 °C; storage ‑20–70 °C; humidity 10–90% non‑condensing.

• Driver Support: NI‑Serial, LabVIEW, Measurement Studio; Windows / LabVIEW Real‑Time compatible.

Interface & Communication Configuration

• Front‑panel I/O: 68‑pin VHDCI → breakout cable to 8 × DB‑9 male for standard serial devices.

• PXIe Interface: Plug‑and‑Play; 3.3 V PCIe signaling; memory‑mapped I/O to avoid resource conflicts.

• Port Configuration: Each port independently set for baud rate, data bits (5–8), parity (none/even/odd), stop bits (1/1.5/2), and protocol (RS‑422/RS‑485).

• Termination: Software‑selectable 120 Ω termination per port (RS‑485).

• COM Port Emulation: Appears as standard Windows COM ports for legacy software compatibility.

Core Features

• 8‑Port High Density: 8 RS‑422/RS‑485 ports in one slot; saves chassis slots.

• 3 Mb/s High Speed: Fast data transfer for high‑throughput test and industrial links.

• DMA & Low CPU: Direct memory access reduces CPU load; ideal for real‑time systems.

• Multi‑Protocol Flexibility: Software‑switchable RS‑422 (4‑wire full‑duplex) / RS‑485 (2‑wire half‑duplex).

• Long‑Range & Multi‑Drop: RS‑485 supports 1.2 km at lower baud rates; up to 32 devices per segment.

• Industrial Reliability: Wide temp range, EMI immunity, and PXIe compliance for harsh environments.

Application Scenarios

• Automated Test Systems: Control multiple RS‑422/RS‑485 instruments (power supplies, meters, scanners) in aerospace, semiconductor, and automotive test benches.

• Industrial Automation: Connect PXIe systems to PLCs, motor controllers, and sensors on factory floors.

• Distributed Data Acquisition: Long‑distance serial links between test nodes in large‑scale systems.

• Legacy Device Upgrades: Integrate modern PXIe systems with existing RS‑422/RS‑485 devices.

• Modbus/Serial Networks: High‑speed Modbus RTU communication in industrial networks.

Usage & Maintenance Instructions

Installation & Configuration

1. Insert into a 3U PXIe chassis slot; secure the front panel.

2. Connect the 68VHDCI‑DB9M cable to the front‑panel VHDCI connector; attach DB‑9 serial devices.

3. Power on the chassis; the OS detects the card via Plug‑and‑Play.

4. Install NI‑Serial drivers; configure ports in NI‑MAX or Device Manager.

5. In LabVIEW, use VISA functions to set baud rate, protocol, and termination.

Daily Maintenance

• Inspect VHDCI/DB‑9 cables and connectors for wear, damage, or loose connections.

• Operate within rated temp/humidity; keep chassis clean and dry.

• Monitor communication via NI‑Serial tools or LabVIEW VISA traces for errors.

• Store idle modules in anti‑static bags in a dry environment.

Safety & Disposal

• Avoid hot‑swapping cables/modules when powered on.

• Do not exceed environmental ratings.

• Dispose of modules per local electronic waste regulations.