Detailed Specifications of NI PXI-6221 Multifunction DAQ Module
The NI PXI-6221 is a high-performance multifunction data acquisition (DAQ) module designed for the PXI bus architecture by National Instruments (NI). It integrates analog I/O, digital I/O, and timing functions, delivering cost-effective and reliable measurement solutions for precision-critical industrial and laboratory applications .
1. Basic Information
- Module Series: Part of NI’s general-purpose DAQ family, optimized for PXI bus.
- Part Numbers: 779418-01, 779066-01 .
- Physical Dimensions: Approximately 23.0 cm × 10.0 cm × 2.1 cm .
- Operating Temperature: -40°C to 85°C (wide-temperature option available) .
- Protection: IP30 rating with reinforced corrugated aluminum housing .
2. Core Technical Specifications
2.1 Analog Input
- Channel Configuration: 16 single-ended channels or 8 differential channels .
- Resolution: 16-bit ADC, ±0.5 LSB accuracy (0.003% of full scale) .
- Sampling Rate: Up to 250 kS/s (single-channel); synchronized acquisition maintained during multi-channel multiplexing .
- Input Range: Switchable across four ranges: ±0.2V, ±1V, ±5V, ±10V .
- Overvoltage Protection: ±25V (powered on), ±15V (powered off) .
2.2 Analog Output
- Channel Count: 2 channels .
- Resolution: 12-bit DAC (0.012% of full scale) .
- Output Range: ±10V, matching analog input range .
2.3 Digital I/O
- I/O Lines: 24 programmable lines (5V TTL/CMOS compatible) .
- Functionality: Supports digital triggering and correlated I/O for external device control (e.g., switches, valves) .
2.4 Counter/Timer
- Configuration: 2 channels of 32-bit counters/timers .
- Clock Source: 20 MHz reference clock for precision timing .
- Supported Tasks: Pulse width measurement, frequency analysis, and event counting .
2.5 Synchronization & Triggering
- Synchronization: Nanosecond-level clock synchronization via PXI backplane, enabling multi-module phase-coherent acquisition .
- Trigger Options: Digital triggering support for precise measurement initiation .
- Signal Conditioning: Compatible with SCC/SCXI modules (e.g., SCXI-1102) for hardware filtering (2Hz low-pass) and 110dB common-mode rejection .
3. Software & Driver Support
- Drivers: NI-DAQmx measurement services, simplifying device configuration and data acquisition workflows .
- Programming Compatibility:
- NI software: LabVIEW (7.x+), LabWindows/CVI (7.x+), Measurement Studio (7.x+), LabVIEW SignalExpress .
- Programming languages: C/C++, MATLAB, Visual Basic .
- Calibration: Integrated NI-MCal algorithm for automatic nonlinearity compensation, achieving ≤0.02% static accuracy and ≤0.3% dynamic accuracy .
4. Typical Application Scenarios
The PXI-6221 excels in cost-sensitive applications requiring high precision, including :
- Industrial Automation: Production line monitoring, process control, and machinery vibration analysis.
- Aerospace & Defense: Wind tunnel model attitude control (Mach number accuracy ±0.2%, 50ms response time) .
- Energy & Utilities: Oil/gas drilling monitoring and power grid signal acquisition.
- Laboratory & Research: Electronic component testing, sensor data logging, and design verification.
- Manufacturing: Automotive electronics testing and semiconductor quality inspection.
5. Selection & Compatibility Notes
- Ideal For: Applications balancing performance and cost, with sampling rate demands <250 kS/s .
- Upgrade Path: For higher throughput (up to 2 MS/s), consider NI PCI-6251; for more analog channels, opt for PCI-6224 (32-channel analog input) .
- System Integration: Supports DMA for high-speed data transfer and seamless integration with NI PXI chassis and third-party industrial equipment .
