Description
NI PXI-6225
I. Basic Information
Model：NI PXI-6225
Brand：National Instruments (NI)
Platform：PXI Bus Modular Test & Measurement Platform
Product Type：High-precision multi-functional M-series DAQ data acquisition module, integrating analog input, analog output, digital I/O and counter/timer functions. It is a universal high-density acquisition module widely used in industrial testing, laboratory measurement and signal acquisition fields, featuring high resolution, high channel density and anti-interference performance.
Product Positioning
The NI PXI-6225 is a 3U standard PXI multi-functional acquisition module equipped with a 16-bit high-precision ADC chip. It provides 80 single-ended / 40 differential configurable analog input channels with a maximum single-channel sampling rate of 250kS/s, adapting to precise acquisition of voltage and weak sensor signals. Integrated with 2 analog output channels, 24 bidirectional digital I/O channels and 2 32-bit counters, it realizes one-stop functions of signal acquisition, analog control, digital logic interaction and pulse measurement. Based on the NI-DAQmx driver architecture, it is compatible with mainstream development environments. It is widely applied in industrial automated testing, structural mechanics testing, environmental monitoring, power parameter acquisition and scientific research data acquisition, serving as the core general module for small and medium-sized multi-channel data acquisition systems and hardware replacement & capacity expansion renovation of old PXI test systems.
Hardware Architecture
Adopting a 3U PXI reinforced board structure with conformal coated PCB and built-in signal filtering, ESD and surge protection circuits, the module consists of six core units: 16-bit high-precision ADC sampling unit, high-density analog input array unit, precision analog output unit, universal digital I/O interaction unit, 32-bit counter/timing unit, and PXI bus communication & hardware protection unit. It supports single-ended/differential mode switching and multi-module high-precision synchronous acquisition via PXI trigger bus and RTSI bus, ensuring stable and low-noise signal acquisition in complex industrial environments.
Mounting & Supporting System
- Mounting: Standard 3U PXI slot embedded installation, compatible with all PXI/PXIe hybrid chassis
- Interface: 68-pin VHDCI high-density shielded terminal
- Driver Software: NI-DAQmx, compatible with NI MAX, LabVIEW, TestStand and mainstream programming platforms
- Supporting Devices: PXI/PXIe chassis, embedded controller, shielded acquisition cables, various sensors and encoders
- Typical Industries: Automotive testing, aerospace structural testing, power monitoring, environmental acquisition, scientific research experiment, industrial equipment fault diagnosis.
Product Characteristics
1. High channel density: 80 single-ended / 40 differential channels integrate multi-point acquisition functions on a single card, simplifying system hardware architecture and reducing equipment cost.
2. 16-bit high-precision acquisition: High-resolution ADC with low temperature drift and low nonlinear error, equipped with hardware filtering to suppress industrial electromagnetic interference and ensure authentic acquisition data.
3. Multi-function integration: Integrating AI/AO/DI/DO/counter functions to meet full-process test requirements of signal acquisition, equipment control and pulse measurement without additional expansion modules.
4. Flexible acquisition modes: Switchable single-ended and differential modes, differential mode effectively eliminates common-mode interference, suitable for long-distance signal transmission and high-interference industrial scenarios.
5. Strong scalability: Support PXI trigger bus and RTSI synchronous bus, realizing multi-module collaborative synchronous testing and convenient system capacity expansion and function upgrading.
6. Excellent compatibility and developability: Mature NI-DAQmx driver with simple programming interface, supporting multiple acquisition modes and shortening test program development cycle.
II. Technical Specifications
2.1 Analog Input
- Channels: 80 Single-ended / 40 Differential (configurable)
- Resolution: 16-bit ADC
- Max Sampling Rate: 250 kS/s (single channel)
- Programmable Input Range: ±0.1V, ±0.2V, ±0.5V, ±1V, ±2V, ±5V, ±10V
- Input Impedance: ＞10 GΩ
- Typical Nonlinearity: ±0.0015% FS
2.2 Analog Output
- Channels: 2 independent analog output channels
- Resolution: 16-bit DAC
- Output Range: ±10V
- Max Update Rate: 833 kS/s
- Typical Linearity Error: ±0.002% FS
2.3 Digital I/O
- Channels: 24 bidirectional programmable channels
- Logic Level: TTL/CMOS compatible
- Single Channel Output Current: Max 24mA
2.4 Counter/Timer
- Channels: 2 independent 32-bit counters
- Max Input Frequency: 80 MHz
- Functions: Pulse counting, frequency/period measurement, encoder speed measurement, PWM output
2.5 Environmental Parameters
- Operating Temperature: 0℃ ~ +55℃
- Storage Temperature: -20℃ ~ +70℃
- Humidity: 10%~90%RH (non-condensing)
- Ingress Protection: IP20
III. Key Features
1. High-density multi-channel synchronous acquisition realizes accurate collection of multi-point temperature, pressure, vibration and voltage signals, adapting to multi-measuring-point synchronous monitoring scenarios.
2. High-precision analog output provides stable programmable voltage signals for sensor calibration, actuator closed-loop control and signal simulation.
3. Universal digital I/O realizes external equipment state acquisition and switch interlock control, meeting the timing control and interactive requirements of automated test lines.
4. High-speed counter module completes high-frequency pulse measurement, speed positioning and dynamic parameter monitoring for motion control and equipment condition detection.
5. Diverse trigger modes and multi-bus synchronous architecture ensure consistent timing of multi-channel and multi-module test data.
6. Hardware-timed continuous acquisition supports long-term lossless data collection and real-time transmission, suitable for 24-hour uninterrupted monitoring and scientific research experiments.
IV. Working Principle
After power-on and hardware self-inspection of the PXI chassis, the module is automatically identified and initialized by the NI-DAQmx driver. The upper computer configures acquisition parameters such as channel mode, sampling rate and trigger mode. The external analog signal is filtered, amplified and converted into digital signal by the onboard ADC, then uploaded to the controller via the PXI bus. The analog output, digital I/O and counter work independently according to configuration instructions. Supported by the PXI trigger bus, multi-module synchronous timing is realized to ensure accurate and consistent test data. The built-in hardware self-diagnosis function feeds back abnormal states in real time to guarantee system operational stability.
V. Application Scenarios
1. Industrial automated testing: Batch functional testing and signal verification of automotive parts and electronic products.
2. Structural mechanics testing: Multi-channel synchronous acquisition of vibration, stress and strain for aerospace and rail transit equipment.
3. Scientific research experiments: Long-term continuous monitoring and data collection of multi-physics field signals in laboratories.
4. Power and new energy industry: Electrical parameter acquisition and electronic control system signal testing.
5. Equipment condition monitoring: Multi-channel collection of equipment vibration, temperature and noise for fault early warning and traceability.
6. Old system renovation: Upgrade of low-precision and low-density DAQ modules to improve test system performance.
