Part Code Definition

PXI = standard PXI bus specification;

8423 = 4‑channel isolated RS485/422 variant in NI 8420 series serial card; suffix -01 stands for standard industrial temperature version.

Technical Specifications

Channel Configuration：4 fully independent isolated RS422/RS485 channels, separate transceiver & buffer per port

Baud Rate Range：120 bps ~ 921.6 kbps maximum per channel

Isolation Parameter：2500 Vrms galvanic isolation between each serial port and PXI backplane; ±15 kV ESD protection for all field signal pins

Onboard Buffer：4 kB TX + 4 kB RX FIFO hardware buffer per channel to avoid burst data overflow

Termination & Bias：software configurable 120Ω line termination resistor and bus bias pull-up/down resistor on each port for RS485 multi-drop bus topology

Environment：0~55℃ operating temperature, -40~85℃ storage temperature, RH 5%~95% non-condensing; conforms CE & RoHS certification

Dimension：standard 3U PXI card size, occupies single chassis slot

Interface & Communication Configuration

Front Connector：single 10‑pin modular terminal block on front panel, matched with optional custom cable converting to DB9 pinout for field wiring

Backplane Bus：32bit/33MHz PXI peripheral bus, access PXI trigger bus for hardware synchronous serial triggering with DAQ/motion modules in same chassis

Driver Support：NI‑Serial driver suite, compatible LabVIEW, LabWindows/CVI, TestStand, supports standard Windows API serial programming and Modbus/DF1/ASCII industrial protocols

Core Functions

1.Isolated differential serial communication: suppress industrial EMI and ground potential difference damage for long-distance field wiring

2.Multi-drop RS485 bus networking: single bus connects up to 31 slave instruments/sensors with software-controlled bus termination

3.Hardware FIFO buffering: stable continuous high-speed data streaming without host CPU frequent interrupt

4.Software auto direction switch for half-duplex RS485, no external RTS control wiring required

5.Channel independent configuration: separate baud rate, parity, flow control setting on each of four ports without mutual interference

Application Scenarios

Automotive ECU bench test serial communication, factory PLC & field sensor data collection, aerospace ATE test bench instrument linking, environmental monitoring multi-sensor bus acquisition, legacy PXI automation system spare replacement for PXI‑8186 controller chassis.

Operation & Maintenance Notes

Use shielded twisted-pair cable for RS485 field wiring; enable onboard 120Ω termination only at two bus endpoints to prevent signal reflection; avoid hot plug field wiring under powered status to protect isolation transceiver; regularly inspect cable shielding grounding in high-frequency inverter workshop environment.