II. Model Interpretation

PXI: 3U single slot, standard PXI bus (compatible with PXIe mixed slots)

6521: 652x Isolation Relay DIO Series, 8 DI + 8 Relay DO basic model

Architecture: 8 independent isolation DI; 8 relays (3×SPDT + 5×SPST), non-latch

Part Number: 779313-01

Position: Preferred for medium and small power AC/DC load switches, high isolation safety type

III. Technical Parameters (25℃)

1. Digital Input (DI)

Channels: 8 independent isolation DI (Sink/Source compatible)

Voltage range: -30 VDC to +30 VDC

Logic threshold: High ≥ +11 V, Low ≤ +4 V (24 V industrial standard)

Isolation: Channel-to-channel 60 VDC continuous, 620 Vrms/5 s withstand voltage; Channel-ground / Bus 150 VDC continuous

Input filtering: Software programmable 1 μs to 1 ms (debouncing)

Response delay: Typical 100 μs

2. Relay Output (DO)

Channels: 8 mechanical relays (3×SPDT + 5×SPST), non-latch

Switch voltage: 0 to 150 VAC/VDC

Switch current: 2 A/channel continuous

Switch power: 60 W/60 VA max

Action time: Typical 2 ms, maximum 4 ms

Life: Mechanical 100 million times; Electrical (125 VAC/30 VDC) 100,000 to 500,000 times

Power-on state: Programmable (full off / full on)

Watchdog: Software failure automatic safe state (settable)

3. Physical and Environmental

Size: 3U single slot (22×124×126 mm)

Operating temperature: 0 to 55℃

Power consumption: 100 mA@3.3 V, 300 mA@5 V (approximately 1.8 W)

Certification: UL, CE, measurement category II (≤150 V)

IV. Interface and Communication Configuration

Front panel interface: 37-pin key-controlled D-SUB female connector (secure design against incorrect insertion)

Adapter cable: SH37-37, R3705050 (37-pin adapter)

Terminal box: CB-37, SCB-37A (with isolation terminals)

Bus: PXI (PCI, trigger, 10 MHz reference clock)

Driver: NI-DAQmx 9.0+, supports LabVIEW, Python, C#, TestStand

Synchronization: PXI trigger bus, multi-module synchronization control

V. Core Functions

8 isolation DI + 8 power relay DO: Single card monitoring 8 24 V sensors + 8 150 V/2 A AC/DC loads, no external relays required, isolation between channels to prevent ground loop current, 150 V isolation level suitable for medium-voltage scenarios.

Industrial-grade safety mechanism: key-controlled connector + watchdog + programmable power-on + input filtering + change detection, anti-insertion, automatic protection in case of software failure, power-on safe state, contact debouncing to prevent incorrect triggering.

±30 V wide voltage bidirectional input: compatible with NPN/PNP sensors, suitable for global 24 V industrial standard.

Mechanical relay high-reliability switch: 150 V/2 A/60 W direct drive, long mechanical life, applicable to AC/DC, suitable for frequent switching scenarios.

Compact 3U single slot: 16 channels high density, saves chassis slots, suitable for small-scale I/O systems. Industrial Automation "Monitoring + Power Switch": PLC expansion relay DIO, 24 V sensor acquisition + 150 VAC contactor / valve control, production line status feedback + high-power actuator drive.

Power and Energy System: Low-voltage switch cabinet status monitoring + closing/open control, relay coil drive, position feedback of small circuit breakers.

Automotive Electronic Testing: BCM analog quantity acquisition + lighting / wiper / door lock load driving, 12/24 V system power loop control.

ATE and Test System: Test fixture status acquisition + relay matrix control, power circuit on/off, safety interlock signal closed loop.

Building / HVAC Control: Fan / pump / valve switch control, sensor status monitoring, lighting circuit control.

VII. Installation and Maintenance Instructions

Installation and Power On

Disconnect the power plug, ensure the chassis is reliably grounded; after powering on, NI-DAQmx self-checks, no preheating required.

Operating Temperature: 0–55℃, keep the air duct unobstructed, avoid overloading due to high temperature.

Wiring and Operation

The 37-pin key-controlled interface must not use mismatched cables; it is recommended to use the CB-37 isolation junction box for intermediate transfer.

Input Voltage: ≤±30 V, Output Voltage: ≤150 VAC/VDC, Current: ≤2 A,严禁 short circuit； Use shielded twisted pair for long-distance， keep away from strong electricity / motors.

Filtering Time： Set according to contact characteristics (10–50 ms)， Watchdog Timeout Time： Set according to safety requirements (100–500 ms).

Daily Maintenance

Keep interfaces clean， prevent dust accumulation in long-term idle state； No calibration required， regularly check the tightness of connection terminals.

Replace relays in time when their lifespan expires to avoid poor contact； Regularly conduct insulation tests on the isolation layer (60 VDC/1 minute).