II. Model Interpretation

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

2520: 2500 series (general-purpose relay switch), 20 represents 80 channels, 150V/2A, electromechanical SPST type.

Part Number: 778572-20NI.

Status: In stock (NI mainstream high-density general-purpose switch module).

III. Technical Parameters

Channel Configuration

Relay Type: 80 independent SPST (Form A, normally open) non-retentive armature relay.

Topology: 80 independent channels, no matrix / multiplexing structure.

Electrical Characteristics

Maximum switching voltage: 150 VDC.

Maximum switching current: 2 A (per channel).

On-state resistance: <0.5 Ω (typical).

Thermal offset: Low (suitable for precise measurement).

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

Dynamic Performance

Bandwidth: 35 MHz.

Switching Time: <5 ms (typical).

Scan Rate: 145 cycles/second.

Physical and Environmental

Size: 3U PXI (100 mm × 160 mm).

Weight: Approximately 0.35 kg.

Operating Temperature: 0–55 °C; Storage: −40–70 °C.

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

IV. Interface and Communication Configuration

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

Signal Interface: 160-pin DIN connector (front panel), divided into 8 groups × 10 channels, facilitating grouped wiring and maintenance.

Trigger and Synchronization: PXI trigger line (70 ns resolution), supports multi-module synchronous scanning and timing control.

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

V. Core Functions

High-density Independent Channels: 80 fully independent SPST, no need to share the bus, suitable for independent on-off control of multiple nodes' signals.

Medium-power Switching Capacity: 150 V/2 A, covers low-voltage power supply, sensors, actuators (heaters, fans, solenoid valves) control requirements.

Low-resistance Low-noise Precise Switching: <0.5 Ω on-state resistance + low thermal offset, suitable for precise voltage/current signal routing and measurement.

Built-in Relay Counting: Built-in relay operation count, facilitating predictive maintenance and early replacement of aging relays.

Software Programmable and Scanning: Supports immediate control and list scanning, suitable for automated test sequences and real-time control scenarios.

VI. Application Scenarios

Automation Testing (ATE): Power / signal routing for circuit boards, modules, systems, functional testing and aging testing.

Power and Load Control: Low-voltage power distribution, relay/contactor drive, heater/fan/电磁阀 control.

Signal Conditioning and Routing： Sensor signals， analog/digital signals switching and distribution， suitable for multi-channel testing systems.

Industrial Control and Monitoring： Equipment status monitoring， alarm circuit control， small actuator drive.

Automotive Electronic Testing： Onboard ECU， sensors， actuators' power and I/O interface testing.

VII. Installation and Maintenance Instructions

Installation and Wiring

Module： Power off and plug out， insert into PXI/PXIe hybrid slot， tighten the fixing screws.

Wiring： Connect the load / tested equipment according to the channel definition of the 160-pin DIN connector， strictly prohibit exceeding 150 V， 2 A. Grounding: The chassis is reliably connected to the system ground to reduce electromagnetic interference.

Software configuration

Install the NI-SWITCH driver and the NI-MAX identification module, and configure the channel topology.

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

Daily maintenance

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

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

Protection mechanism: Avoid overvoltage (>150 V), overcurrent (>2 A), inductive loads (without surge suppression), to extend the relay lifespan.

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