II. Model Interpretation

PXI: PCI eXtensions for Instrumentation, compatible with PXI/PXIe hybrid slots.

2527: 2500 series (multiplexer), 27 represents 32-channel 2-wire, 300V, latch relay specification.

Part Number: 778572-27.

Status: In stock (NI's mainstream high-voltage multiplexer).

III. Technical Parameters Channel configuration

Relay type: Electromechanical latch relay (power-off retention state).

Topology: 64×1 (1-wire), 32×1 (2-wires), 16×1 (4-wires), supports independent channel control.

Electrical characteristics

Maximum switching voltage: 300 VDC/300 VAC (channel-to-channel / channel-to-ground, CAT I).

Maximum switching current: 2 A (per channel, switching / carrying).

Maximum switching power: 60 W, 62.5 VA (DC–60 Hz, per channel).

On-resistance: <1 Ω (typical).

Relay lifespan: 10^7 times (resistive load, typical).

Contact material: Palladium-ruthenium alloy plated with gold (low contact resistance, corrosion-resistant).

Dynamic performance

Scan rate: 140 cycles/second.

Switching time: <5 ms (typical).

Physical and environmental

Size: 3U PXI (21.6 cm×2.0 cm×13.0 cm).

Weight: 209 g.

Operating temperature: 0–55 °C; Storage: −20–70 °C.

Humidity: 10%–90% RH (no condensation).

Power consumption: 6 W (5 V), 2.5 W (3.3 V).

IV. Interface and Communication Configuration

Host interface: PXI mixed bus (compatible with PXIe/PXI), supports hot plugging, plug-and-play.

Signal interface: 100-pin HDI right-angle male connector (front panel), compatible with 1/2/4-wire topology wiring.

Trigger and synchronization: PXI trigger lines (0–7), supports hardware triggering, multi-module synchronous scanning NI.

Driver software: Compatible with NI- SWITCH, LabVIEW, TestStand, C/C++/Python API, supports IVI standard driver.

V. Core Functions

Multi-topology multiplexing: **64×1 (1-wire), 32×1 (2-wires), 16×1 (4-wires)** flexible configuration, suitable for single-ended / differential / resistance measurement (4-wire Kelvin).

300V high-voltage switching: 300V/2A coverage for industrial high-voltage signals, power supplies, sensor measurements, supports 1500V pulse withstand voltage.

Latch relay low power consumption: retains channel state during power-off, no need for continuous power supply, reduces system power consumption.

Built-in relay count: Built-in action count statistics, supports predictive maintenance, early replacement of aging relays.

High-speed scanning and deterministic triggering: 140 cycles/second scanning rate, hardware triggering synchronization, improves test throughput.

VI. Application Scenarios

High-voltage automated test (ATE): multi-channel voltage / current / resistance inspection for industrial equipment, power modules, high-voltage sensors.

PXI multimeter channel expansion: with NI 4070/4072 DMM, achieve 64-channel single-ended / 32-channel differential signal measurement.

Battery and power test: multi-channel voltage / internal resistance testing for high-voltage battery packs, DC-DC modules.

Industrial signal monitoring: status monitoring and data acquisition for high-voltage sensors, transmitters, actuators.

Automotive electronic high-voltage testing: signal acquisition and verification for vehicle high-voltage systems (such as battery management system BMS).

VII. Usage and Maintenance Instructions

Installation and wiring

Module: Power-off insertion and removal, insert into PXI/PXIe mixed slot, tighten the fixing screws.

Wiring: Connect according to topology definition for 100-pin HDI interface, strictly prohibit exceeding 300V, 2A, only CAT I signals.

Grounding: Reliable connection of chassis and system ground to reduce electromagnetic interference and static damage.

Software configuration Install the NI-SWITCH driver, the NI-MAX identification module, and configure 1/2/4 line topologies.

Programming: Call the switch VI in LabVIEW, or configure the test sequence in TestStand to achieve channel scanning and measurement synchronization.

Daily maintenance

Cleaning: After power off, wipe the panel with a soft cloth to avoid liquid entering the HDI interface.

Environment: Working temperature 0–55°C. Avoid dust, moisture, and strong electromagnetic interference.

Protection mechanism: Avoid overpressure (>300V), overcurrent (>2A), inductive loads (without surge suppression), to extend the relay lifespan.

Static protection: Wear an anti-static wristband when plugging or unplugging the module to ensure good grounding of the chassis.