Product Introduction
The NI PXI-6221 is an M Series multifunction data acquisition (DAQ) module designed for automated testing, laboratory measurement, industrial monitoring, sensor acquisition, and general-purpose PXI measurement systems. It combines analog input, analog output, digital I/O, and counter/timer functionality in a single modular instrument.
Featuring 16 single-ended or 8 differential analog inputs, 16-bit resolution, a maximum aggregate analog input sampling rate of 250 kS/s, two analog outputs, 24 digital I/O lines, and two 32-bit counter/timers, the PXI-6221 provides a versatile solution for multifunction data acquisition and control applications.
Product Overview
The NI PXI-6221 belongs to the NI M Series multifunction DAQ family and is designed to consolidate multiple measurement and control functions into a single PXI module.
Its analog input subsystem supports up to 16 single-ended or 8 differential measurement channels with 16-bit resolution. The multiplexed acquisition architecture provides an aggregate sampling rate of up to 250 kS/s, making the module suitable for general-purpose voltage acquisition, sensor measurements, electronic validation, and automated data logging.
Unlike input-focused DAQ modules such as the PXI-6225, the PXI-6221 also provides two analog output channels. Combined with digital I/O and counter/timer resources, this enables the module to perform stimulus, measurement, control, and timing functions within the same PXI test system.
Key Features
16 Analog Input Channels
The PXI-6221 provides flexible analog input configurations for general-purpose voltage and sensor measurements.
- 16 single-ended analog inputs
- 8 differential analog inputs
- Multi-channel voltage acquisition
- Sensor signal measurement
- Automated data logging
Advantage: The configurable input architecture allows engineers to balance channel count and differential measurement requirements according to the application.
16-Bit Analog Input Resolution
The PXI-6221 uses 16-bit analog-to-digital conversion for general-purpose measurement applications.
- 16-bit ADC resolution
- Voltage signal acquisition
- Sensor measurements
- Electronic characterization
- Repeatable automated measurements
Advantage: Provides suitable measurement resolution for a broad range of laboratory, industrial, and automated test applications.
250 kS/s Analog Input Sampling
The PXI-6221 supports a maximum aggregate analog input sampling rate of up to 250 kS/s.
- Up to 250 kS/s aggregate sampling
- Hardware-timed acquisition
- Multi-channel data acquisition
- Waveform monitoring
- Automated measurement applications
Advantage: Provides a practical combination of acquisition speed and multifunction capability for general-purpose PXI test systems.
Multiplexed Analog Input Architecture
The PXI-6221 uses a multiplexed analog input architecture in which multiple input channels share the analog-to-digital conversion subsystem.
- Efficient multi-channel acquisition
- Sequential channel scanning
- Flexible channel configuration
- Compact multifunction architecture
- General-purpose measurement capability
Advantage: Multiplexing enables multiple analog input channels to be integrated economically into a compact multifunction PXI module.
2 Analog Output Channels
In addition to analog acquisition, the PXI-6221 provides two analog output channels for generating programmable voltage signals.
- 2 analog output channels
- 16-bit analog output resolution
- Programmable voltage generation
- Stimulus generation
- Closed-loop test applications
Advantage: Analog input and output functionality can be combined within one module for stimulus-and-response testing and basic control applications.
24 Digital I/O Lines
The PXI-6221 provides 24 digital I/O lines for interfacing with external digital devices, test fixtures, and control hardware.
- 24 digital I/O lines
- Digital input monitoring
- Digital output control
- Test fixture interfacing
- Device status monitoring
Advantage: Digital control functions can be integrated with analog acquisition and generation without requiring a separate general-purpose digital I/O module.
Two 32-Bit Counter/Timers
The PXI-6221 includes two 32-bit counter/timers for hardware-timed measurement and generation applications.
- Event counting
- Frequency measurement
- Period measurement
- Pulse-width measurement
- Pulse generation
- Encoder-related measurements
Advantage: Counter/timer resources extend the module’s functionality beyond conventional analog and digital data acquisition.
Hardware Timing and Triggering
The PXI-6221 supports hardware timing and triggering for repeatable automated measurement sequences.
- Hardware-timed analog acquisition
- External triggering
- Sample clock control
- PXI trigger integration
- Coordinated measurement sequences
Advantage: Hardware timing provides more deterministic and repeatable measurements than software-timed acquisition alone.
PXI System Integration
The PXI-6221 can be installed alongside other PXI instruments to create complete automated test and measurement systems.
- PXI modular architecture
- Multi-instrument integration
- Shared PXI triggering resources
- Compact test system design
- Scalable measurement architecture
Advantage: Engineers can combine multifunction DAQ with switching, DMM, oscilloscope, signal generation, communication, and timing modules within a unified PXI platform.
NI-DAQmx Software Support
The PXI-6221 is supported by NI-DAQmx for hardware configuration, acquisition, generation, timing, triggering, and application development.
- NI-DAQmx support
- LabVIEW integration
- NI MAX configuration
- TestStand integration
- C/C++ and .NET development
Advantage: Provides an established software ecosystem for developing customized data acquisition and automated test applications.
Technical Specifications
| Parameter | Description |
|---|---|
| Product Type | PXI M Series Multifunction DAQ Module |
| Analog Input Channels | 16 Single-Ended / 8 Differential |
| Analog Input Resolution | 16-bit |
| Maximum Analog Input Sample Rate | 250 kS/s Aggregate |
| Analog Input Architecture | Multiplexed |
| Maximum Analog Input Range | ±10 V |
| Analog Output Channels | 2 |
| Analog Output Resolution | 16-bit |
| Analog Output Range | ±10 V |
| Digital I/O | 24 Lines |
| Counter/Timers | 2, 32-bit |
| Timing | Hardware Timed |
| Triggering | Analog and Digital Triggering Support |
| Bus Platform | PXI |
| Product Family | NI M Series Multifunction DAQ |
| Driver | NI-DAQmx |
| Primary Applications | Multifunction DAQ, Automated Test, Sensor Measurement and Laboratory Data Acquisition |
Software Ecosystem
The NI PXI-6221 integrates with NI software tools for measurement configuration, data acquisition, signal generation, analysis, visualization, and automated testing.
- NI-DAQmx: Provides configuration and programming APIs for analog input, analog output, digital I/O, counters, timing, and triggering.
- LabVIEW: Enables development of customized acquisition, control, visualization, data logging, and automated measurement applications.
- NI MAX: Provides hardware detection, configuration, self-test, diagnostics, and basic hardware testing.
- TestStand: Enables PXI-6221 measurements and control functions to be incorporated into automated validation and production test sequences.
- C/C++ and .NET: Support customized test and measurement application development through compatible NI-DAQmx APIs.
Industries
- Automated Test
- Electronic Manufacturing
- Industrial Automation
- Automotive Testing
- Aerospace and Defense
- Electromechanical Testing
- Research and Development
- Scientific Laboratories
Applications
General-Purpose Data Acquisition
The PXI-6221 provides a balanced combination of analog, digital, and timing resources for general-purpose PXI data acquisition.
- Voltage acquisition
- Multi-channel measurements
- Data logging
- Laboratory instrumentation
Automated Electronic Testing
The multifunction architecture makes the PXI-6221 suitable for automated electronic validation and production test systems.
- Functional testing
- Electronic subsystem validation
- Production testing
- Automated measurement sequences
Stimulus and Response Testing
The combination of analog input and analog output enables the PXI-6221 to generate test signals and measure resulting responses.
- Programmable voltage stimulus
- Device response measurement
- Component characterization
- Automated functional testing
Sensor Measurement
When paired with appropriate sensors and signal conditioning, the PXI-6221 can acquire a variety of physical measurement signals.
- Pressure measurement
- Position measurement
- Force and load measurement
- General-purpose transducer acquisition
Industrial Monitoring and Control
Analog input, analog output, digital I/O, and counter resources allow the PXI-6221 to perform measurement and basic control functions.
- Machine monitoring
- Process measurement
- Equipment diagnostics
- Automated control systems
Counter and Frequency Measurement
The integrated counter/timers can be used for digital timing and event measurement applications.
- Frequency measurement
- Event counting
- Period measurement
- Pulse-width measurement
- Encoder measurements
Research and Laboratory Measurement
The PXI-6221 provides a programmable multifunction measurement platform for engineering and scientific laboratories.
- Experimental data acquisition
- Prototype characterization
- Automated laboratory testing
- Engineering research
Comparison with Similar PXI DAQ Modules
| Model | Main Difference | Best Application |
|---|---|---|
| NI PXI-6221 | 16-bit multifunction M Series DAQ with 16 single-ended analog inputs, two analog outputs, digital I/O, and counter/timers. | General-purpose multifunction data acquisition |
| NI PXI-6225 | High-channel-count M Series DAQ providing up to 80 single-ended analog inputs for systems requiring significantly more measurement channels. | High-density analog input acquisition |
| NI PXI-6251 | Higher-performance M Series multifunction DAQ with faster analog input sampling for more demanding automated measurement applications. | Higher-speed general-purpose multifunction DAQ |
| NI PXI-6280 | High-accuracy M Series DAQ featuring 18-bit analog input resolution for applications prioritizing precision. | High-accuracy analog measurement |
Recommended Related Products
| NI PXI-6225 | High-channel-count M Series DAQ module for applications requiring substantially more analog measurement channels. |
| NI PXI-6251 | Higher-performance multifunction DAQ module for applications requiring faster analog acquisition and broader measurement capability. |
| NI PXI-6280 | 18-bit high-accuracy multifunction DAQ module for precision voltage and sensor measurement applications. |
| NI PXI-6722 | Dedicated PXI analog output module for systems requiring a larger number of programmable analog output channels. |
Why Choose PXI-6221?
- 16 single-ended or 8 differential analog inputs
- 16-bit analog input resolution
- Up to 250 kS/s aggregate analog input sampling
- 2 analog output channels
- 24 digital I/O lines
- Two 32-bit counter/timers
- Hardware timing and triggering
- PXI modular system integration
- NI-DAQmx and LabVIEW support
- Suitable for measurement, stimulus, control, and automated testing
Frequently Asked Questions
What is the NI PXI-6221?
The NI PXI-6221 is an M Series multifunction PXI data acquisition module that combines analog input, analog output, digital I/O, and counter/timer functionality for automated test and general-purpose measurement applications.
How many analog input channels does the PXI-6221 have?
The PXI-6221 provides up to 16 single-ended analog input channels or 8 differential analog input channels.
What is the analog input resolution of the PXI-6221?
The PXI-6221 provides 16-bit analog input resolution, making it suitable for general-purpose voltage, sensor, laboratory, and automated test measurements.
What is the maximum sampling rate of the PXI-6221?
The PXI-6221 supports a maximum aggregate analog input sampling rate of 250 kS/s. Because the module uses a multiplexed analog input architecture, this specification should not be interpreted as a simultaneous 250 kS/s rate for every analog input channel.
Does the PXI-6221 have analog outputs?
Yes. The PXI-6221 provides two 16-bit analog output channels, allowing the module to generate programmable voltage signals for stimulus, control, and automated test applications.
How many digital I/O lines does the PXI-6221 provide?
The PXI-6221 provides 24 digital I/O lines for interfacing with external devices, monitoring digital states, controlling test fixtures, and implementing automated test logic.
Does the PXI-6221 include counter/timers?
Yes. The PXI-6221 provides two 32-bit counter/timers that can be used for event counting, frequency measurement, period measurement, pulse-width measurement, pulse generation, and related timing applications.
What is the difference between PXI-6221 and PXI-6225?
The PXI-6221 is a general-purpose multifunction DAQ module with 16 single-ended analog inputs and two analog outputs. The PXI-6225 is designed primarily for high-channel-count acquisition and provides up to 80 single-ended analog inputs but does not provide onboard analog outputs. The PXI-6221 is therefore more suitable when multifunction input and output capability is required, while the PXI-6225 is better suited to systems prioritizing analog input channel density.
What is the difference between PXI-6221 and PXI-6251?
Both belong to the NI M Series multifunction DAQ family. The PXI-6221 provides up to 250 kS/s aggregate analog input sampling, while the PXI-6251 offers higher analog acquisition performance. The PXI-6221 is suitable for general-purpose applications where moderate sampling speed is sufficient, while the PXI-6251 is preferable for faster measurement requirements.
What software supports the PXI-6221?
The PXI-6221 is supported by NI-DAQmx and can be integrated with LabVIEW, NI MAX, TestStand, and compatible C/C++ and .NET development environments.
Conclusion
The NI PXI-6221 M Series multifunction DAQ module provides a balanced solution for automated data acquisition, signal generation, digital control, timing, and laboratory measurement. With 16 single-ended or 8 differential analog inputs, 16-bit resolution, up to 250 kS/s aggregate sampling, two analog outputs, 24 digital I/O lines, two 32-bit counter/timers, hardware timing, and NI-DAQmx support, the PXI-6221 is well suited for general-purpose PXI automated test and measurement systems.
