Detailed Specifications of NI PXIe-6704 Precision Analog Output Module

1. Basic Information

• Module Series: PXIe Precision Analog Output Module (DAQ)
• Part Number: 781064-01 (standard model)
• Physical Dimensions: 1-slot 3U PXIe form factor, 10.0 cm × 16.0 cm (width × length)
• Weight: Approximately 0.6 kg (1.32 lbs)
• Power Requirements:
  • +3.3 V DC (1.2 A)
  • +12 V DC (1.0 A)
  • -12 V DC (0.8 A)
  • Power Consumption: Typical 15 W, Maximum 20 W
• Interface Type:
  • PXIe x1 lane (up to 8 GB/s data transfer rate) for fast waveform updates
  • 1 68-pin SCSI-II connector (for analog output signals and auxiliary I/O)
  • 1 10-pin header (for external trigger and clock signals)
• Operating Temperature Range: 0°C ~ 55°C (commercial grade)
• Environmental Ratings:
  • Shock Resistance: 50 g peak (11 ms duration, half-sine)
  • Vibration Resistance: 2 g RMS (10 Hz ~ 500 Hz, random)
  • Ingress Protection: IP30 (prevents solid foreign object intrusion)
• Compliance: Meets FCC Part 15 Class A, CE EN 61326-1, UL 61010-1, and IEC 61010-1 safety & EMC standards

2. Core Technical Specifications

2.1 Analog Output Channels

• Channel Count: 8 independent, software-configurable channels (no channel sharing)
• Resolution: 16 bits (65,536 discrete levels)
• Output Types:
  • Voltage Output: Primary mode (default)
  • Current Output: Supported via external current-shunt resistors (optional, for current-loop control)
• Voltage Output Ranges (software-selectable per channel):
  • Bipolar: ±0.1 V, ±0.2 V, ±0.5 V, ±1 V, ±2 V, ±5 V, ±10 V
  • Unipolar: 0 V ~ 0.1 V, 0 V ~ 0.2 V, 0 V ~ 0.5 V, 0 V ~ 1 V, 0 V ~ 2 V, 0 V ~ 5 V, 0 V ~ 10 V
• Output Impedance: ≤0.1 Ω (voltage mode, typical)
• Maximum Output Current: ±20 mA per channel (continuous), ±50 mA (peak, 100 ms duration)

2.2 Key Performance Metrics

• Linearity: Integral Nonlinearity (INL) ≤ ±1 LSB (maximum, over full temperature range)
• Accuracy:
  • Voltage Accuracy: ±0.01% of Full Scale (FS) ± 2 LSB (typical, at 25°C, ±10 V range)
  • Temperature Coefficient: ±50 ppm/°C (maximum, for gain and offset)
• Noise Performance:
  • Output Noise: ≤10 µVrms (typical, 10 Hz ~ 100 kHz bandwidth, ±10 V range)
  • Noise Peak-to-Peak: ≤50 µVpp (typical, 0.1 Hz ~ 10 Hz bandwidth)
• Settling Time: ≤10 µs (to within 0.1% of final value, ±10 V range)
• Update Rate:
  • Single Channel: Up to 1 MS/s (megasample per second)
  • Multi-Channel (Simultaneous): Up to 125 kS/s per channel (synchronized update)

2.3 Waveform Generation Capabilities

• Waveform Types:
  • Predefined Waveforms: Sine, square, triangle, sawtooth, DC (programmable amplitude/frequency)
  • Arbitrary Waveforms: User-defined via CSV/TXT files or LabVIEW; supports waveform lengths up to 16 MSa (via PXIe DMA transfer)
• Playback Modes:
  • Continuous: Loop waveform indefinitely
  • Single-Shot: Play waveform once (triggered or software-initiated)
  • Burst: Play waveform N times (N = 1 ~ 1,000,000 cycles)
• Onboard Memory: 512 kSa (shared across 8 channels) for buffer-based waveform playback (reduces host CPU load)

3. Synchronization & Triggering

3.1 Clock Sources

• Internal Clock: 100 MHz precision oscillator (stability ±50 ppm/year) for standalone operation
• External Clock: 10 Hz ~ 10 MHz clock input (via 10-pin header) for synchronization with external instruments (e.g., DAQs, signal generators)
• PXIe Backplane Clock: Synchronizable with PXIe 10 MHz backplane clock for multi-module alignment (e.g., with NI PXIe-6358 DAQ for input-output synchronization)

3.2 Trigger Options

• Digital Trigger:
  • Input Trigger: TTL-compatible edge trigger (rising/falling) via external trigger pin or PXIe trigger lines (PXIe_Trig 0~7)
  • Output Trigger: TTL pulse output (programmable width: 1 µs ~ 1 s) to synchronize downstream devices
• Software Trigger: API-initiated trigger (via LabVIEW/C/C++ code) for automated test sequences
• Synchronized Update: All 8 channels can be updated simultaneously (edge-aligned to clock) for multi-axis control (e.g., robotic arm positioning)

4. Software & Driver Support

• Core Drivers:
  • NI-DAQmx Driver (required for low-level hardware control, channel configuration, and waveform generation)
  • Compatible with NI-DAQmx Base (for cross-platform support: Windows, Linux, macOS)
• Programming Compatibility:
  • NI Ecosystem: Native support for LabVIEW (2018+), LabWindows/CVI, and Measurement Studio (.NET framework)
  • Third-Party Languages: C/C++, C#, Python (via NI-DAQmx Python bindings), and MATLAB (via NI-DAQmx Toolbox)
  • Configuration Tools: NI Measurement & Automation Explorer (MAX) for graphical channel setup, calibration, and self-test
• Calibration:
  • Built-in Automated Calibration: Compensates for gain, offset, and linearity errors (initiated via MAX or NI-DAQmx API)
  • Recommended Calibration Interval: 1 year (or after major temperature changes)
  • External Calibration: Supported via NI Calibration Services (ISO 17025 accredited)

5. Typical Application Scenarios

• Industrial Process Control: Controlling analog actuators (e.g., valves, motors) in manufacturing lines; generating setpoint voltages for PID controllers (e.g., temperature/pressure control)
• Sensor Calibration: Generating precise reference voltages/currents to calibrate sensors (e.g., pressure sensors, thermocouples, strain gauges)
• Analog Signal Simulation: Emulating sensor signals (e.g., 4–20 mA current loops, 0–10 V industrial signals) for testing PLCs (Programmable Logic Controllers) or SCADA systems
• Scientific Research: Controlling laboratory equipment (e.g., syringe pumps, mass spectrometers, optical filters) with high precision; generating stimuli for material testing (e.g., voltage-controlled strain testing)
• Automotive Testing: Simulating analog sensor outputs (e.g., throttle position, coolant temperature) for ECU (Engine Control Unit) validation

6. Selection & Compatibility Notes

• Ideal Use Cases: Applications requiring 8-channel precision analog output, 16-bit resolution, and PXIe integration; suitable for low-to-medium speed control and waveform generation tasks
• Comparison with Similar Modules:
  • vs. NI PXIe-6738: PXIe-6704 offers 8 channels (vs. 16 channels) but lower cost; choose for smaller-scale control systems
  • vs. NI PXIe-5401: PXIe-6704 is for low-speed precision control (vs. high-speed waveform generation); ideal for DC or low-frequency (<100 kHz) signals
• System Compatibility:
  • Chassis: Works with all NI PXIe chassis (e.g., PXIe-1075, PXIe-1082) and third-party PXIe-compliant chassis
  • Companion Modules:
    • Input Validation: Pair with NI PXIe-6358 (analog input DAQ) to measure DUT (Device Under Test) response to generated signals
    • Digital Control: Integrate with NI PXIe-6533 (digital I/O) for combined analog/digital control systems
    • Signal Conditioning: Use NI SCC-68 (terminal block) for safe wiring to industrial sensors/actuators
• Limitations: No built-in current output (requires external shunts); maximum update rate (1 MS/s) insufficient for high-frequency (>100 kHz) waveform generation
• Alternative Models:
  • More Channels: NI PXIe-6738 (16 channels, 16-bit, 1 MS/s)
  • High-Speed Waveforms: NI PXIe-5401 (function generator, 1.2 GS/s)
  • USB Interface: NI USB-6733 (8 channels, 16-bit, for standalone use)