Channel & Physical Interface Configuration

• Counter resources: 8 independent reconfigurable 32-bit up/down counter-timers, no shared resource limitation between channels
• Digital I/O: 32 programmable PFI general-purpose bidirectional TTL/CMOS lines, multiplexed with counter source/gate/out auxiliary signals
• Rear connector: 68-pin shielded latching female SCSI-II connector, matched with SH68-68-D1 shielded cable
• Slot occupation: Single-width 3U PXI peripheral slot; only Slot 2 achieves full 75 ppb OCXO clock optimization
• Dimension & weight: 160 × 100 mm footprint, 225 g bare module weight including OCXO oven circuit

Core Counter/Timer Electrical Parameters

• Counter resolution: Fixed 32-bit non-lossy counting, maximum count value 4,294,967,295
• Native timebases: 100 kHz, 20 MHz, 80 MHz onboard reference clocks; ×2/×8 programmable prescalers
• Max frequency handling: 80 MHz without prescaling, 125 MHz with prescaler enabled
• Minimum edge separation: 25 ns for dual-edge interval measurement, supporting high-speed pulse sequence capture
• Quadrature encoder support: X1/X2/X4 decoding modes, minimum Z-index trigger pulse width 50 ns
• Rollover latency: 53.69 s @ 80 MHz timebase, 214.74 s @ 20 MHz timebase

Exclusive OCXO High-Stability Clock Specifications

• OCXO center frequency: 10.000000 MHz, hardware fine-tunable ±500 ppb for long-term drift correction
• Warm-up requirement: 5 minutes warm-up to reach ±20 ppb accuracy (power-off interval <1 hour)
• Temperature stability: ±5 ppb across 0 ℃ ~ 50 ℃ ambient range referenced to 25 ℃
• Long-term drift: ±0.45 ppb per day, ±45 ppb annual aging drift
• Power supply stability: ±5 ppb frequency deviation under ±5% backplane +5 V supply fluctuation
• Clock output capability: Can drive PXI backplane PXI_CLK10 to upgrade system-wide timing accuracy

Digital I/O Signal Characteristics

• Logic level standard: TTL/CMOS compatible; input low ≤0.8 V, input high ≥2.0 V
• Schmitt trigger hysteresis: Fixed 300 mV for anti-glitch noise suppression on input lines
• Input impedance: 25 kΩ ~ 500 kΩ passive pull-down, 10~200 μA pull-down current
• Output impedance: 75 Ω integrated series resistance for signal impedance matching
• Output drive capability: 4 mA sink/source current, low-level output voltage ≤0.4 V under full load
• Power-on default state: All PFI lines high-impedance input with weak pull-down protection

PXI Bus & DMA Synchronization Resources

• PXI bus compliance: PXI Rev.2.2, supports 6 local trigger lines, 1 star trigger and PXI_Clk10
• DMA channels: 3 independent scatter-gather DMA channels for zero-CPU continuous counter streaming
• Backplane power consumption: 1.0~2.5 A @ +5 V rail, peak power during OCXO warm-up
• Auxiliary I/O power: Onboard isolated +5 V @ 1 A output on rear connector for external sensor power supply
• Multi-module synchronization: Sub-100 ps skew when synchronized via PXI star trigger with DAQ/DMM modules

Isolation &amp; Safety Withstand Ratings

• Channel-to-chassis withstand: ±11 V continuous signal voltage, IEC 61010 CAT I measurement category only
• Channel-to-channel withstand: ±22 V differential continuous voltage between independent PFI lines
• ESD protection: ±15 kV human body model for all PFI pins conforming to IEC 61000-4-2
• Pollution degree: Class 2 indoor dry environment only, max working altitude 2000 m

Mechanical & Environmental Specifications

• Operating temperature: 0 ℃ ~ +55 ℃; Storage temperature: -20 ℃ ~ +70 ℃
• Humidity: 0%–90% non-condensing operation, 5%–95% non-condensing storage
• Shock resistance: 30 g peak half-sine operational shock, 11 ms pulse duration
• Vibration resistance: 0.3 grms operational random vibration, 2.4 grms non-operational storage vibration
• EMC compliance: CE, FCC Class A industrial electromagnetic certification, requires shielded cabling

Compatibility Matching List

• Compatible chassis: PXI-1031, PXI-1042, PXI-1045 all legacy 3U PXI chassis
• Compatible controllers: PXI-8186 and all NI embedded/external PXI system controllers
• Matching accessories: SH68-68-D1 shielded cable, CB-68LP breakout terminal block
• Official status: Fully obsolete, only aftermarket inventory and third-party repair available

Software Compatibility

• Drivers: NI-DAQmx, Traditional NI-DAQ, NI-TIO dedicated timing driver
• Configuration tools: NI MAX, Counter Input/Output Interactive Panel
• Supported software: LabVIEW, LabWindows/CVI, Python PyDAQmx, C# timing development kits
• Supported OS: Windows XP/7/10, Phar Lap ETS real-time operating system

Pros & Limitations

• Pros: Industry-leading OCXO clock stability, 8 fully independent counters, high-speed 125 MHz frequency measurement, low-latency DMA transmission, comprehensive quadrature encoder decoding, system clock cascading capability
• Limitations: No onboard signal galvanic isolation, only CAT I low-voltage safety rating, mandatory 5-minute warm-up for precision use, slot-specific clock performance limitation, incompatible with Windows 11 latest DAQmx