II. Model Interpretation

PXI: Standard PXI bus, compatible with PXI/PXIe mixed slots.

2799: NI high-frequency RF switch series code, representing 40 GHz, 50Ω, dual SPDT, electromechanical relay.

Full name: PXI-2799 40 GHz 50Ω dual SPDT RF relay module.

Topology: 2×SPDT (each channel 1 common terminal, 2 select 1), used for signal routing or bypassing the DUT.

III. Technical Parameters

(1) RF Core Characteristics NI

Topology: 2 independent SPDT (single-pole double-throw)

Impedance: 50Ω

Bandwidth: DC～40 GHz

Insertion Loss: ≤1 dB @40 GHz

Isolation: ≥60 dB @40 GHz

Return Loss: ≥15 dB @40 GHz

Termination: No built-in termination, 50Ω system matching

(2) Electrical Rated Values NI

Maximum switching voltage: 30 VAC (cold switching)

Maximum current: 0.6 A AC

Relay type: Electromechanical relay (EMR)

Action time: ≤5 ms

Mechanical life: 1×10⁶ times (rated load)

Scan rate: 2 times/second

(3) Physical and Environmental

Form: Standard 3U PXI single-slot module

Front-end connector: 2.92 mm (SMA) female ×6 (each channel COM/NO/NC)

Size: 216 mm × 20 mm × 130 mm

Weight: Approximately 0.45 kg

Power supply: PXI backplane 5 V; typical power consumption 4 W

Operating temperature: 0 ℃～55 ℃

Storage temperature: –20 ℃～70 ℃

Humidity: 5%～85%, no condensation

IV. Interface and Communication Configuration

(1) Front-end I/O Interface

2.92 mm female ×6 (2 independent SPDT):

Channel 1: COM1 / NO1 / NC1

Channel 2: COM2 / NO2 / NC2

NO: Normally Open (default direct connection); NC: Normally Closed (connected to DUT); COM: Common terminal

(2) Bus and Software Communication NI

Bus interface: Only supports PXIe mixed slot / PXI peripheral slot

Driver: NI-SWITCH, compliant with IVI specification

Software support: LabVIEW, TestStand, LabWindows/CVI, Python, C, .NET

Basic functions: NI MAX hardware identification, channel configuration, relay status monitoring, life counting

Trigger capability: Supports PXI backplane Trigger 0～7, multi-module synchronous switching

V. Core Functions

Dual independent SPDT routing: Each channel can be independently switched, direct connection (NO) or connected to the DUT (NC), achieving dual-channel parallel testing and signal redundancy switching.

40 GHz bandwidth: DC～40 GHz coverage for microwave and millimeter wave, supports harmonics, RF, and high-speed digital signal switching, suitable for 5G/mmWave testing.

Low insertion loss + high isolation: 40 GHz insertion loss ≤1 dB, isolation degree ≥60 dB, ensuring signal integrity and reducing crosstalk.

Flexible signal path control: One-click bypass / connection to the DUT, suitable for performance comparison and fault diagnosis of amplifiers, filters, mixers, etc.

Relay life monitoring: Built-in counter records the number of on/off times, supports predictive maintenance, reducing unexpected downtime.

Single-slot high density: 3U PXI single-slot integrates 2 SPDT, saves cabinet space, suitable for multi-channel RF testing systems. VI. Application Scenarios

RF Device Comparison Test: Quickly insert / remove the DUT, compare the performance differences between direct connection and access states.

5G / Millimeter Wave Equipment Testing: Adapt to the 5G millimeter wave frequency band with a 40 GHz bandwidth, used for base stations, terminals, and RF chips for high-frequency signal routing.

Harmonic and High Frequency Signal Transmission: Route the high-order harmonics of the PXI RF up-converter, or multiple signal sources to the down-converter.

Redundancy Switching and System Protection: Automatically bypass when a critical path fails, protect the backend instruments, and enhance system reliability.

Satellite / Aviation Electronics Testing: High-frequency signal routing, redundancy switching, adapted to satellite communication, radar, and aviation RF testing requirements.

VII. Differences from PXI-2798

PXI-2798: Dual Transfer (Dual SPDT, with bypass), default COM-NC (accessing DUT).

PXI-2799: Dual SPDT (general routing), default COM-NO (direct connection), more suitable for general signal switching.

VIII. Installation and Maintenance Instructions

(1) Installation and Power On

Only install on PXIe mixed slots or PXI peripheral slots, do not use pure PXIe slots.

Before installation, turn off the power, fully insert the module and tighten the panel screws.

After powering on, confirm the device identification is normal and there are no errors in NI MAX.

(2) Connection and Operation

Use 50Ω 2.92 mm coaxial cable, ensure the connectors are clean and tightened, to avoid signal leakage and reflection.

Cold Switching Operation: Switch the relay when there is no signal to avoid arc damage to the contacts.

Path Configuration: Reset state (default) COM-NO (direct connection); Set state COM-NC (accessing DUT).

Programming Control: Configure channel switching, scan sequence, and trigger synchronization through NI-SWITCH API.

(3) Maintenance and Lifespan

Regularly read the relay on-off times through NI MAX, replace when approaching 1×10⁶ times.

Maintain ventilation and heat dissipation, working temperature ≤ 55 ℃, avoid accelerating aging due to high temperature.

Avoid overpressure and overcurrent operations, prevent contact oxidation or adhesion.

When not in use for a long time, store in a dry environment (-20 ℃ to 70 ℃), cover the interface with a dust cap.