Модули PXI

NI PXI Modules and PXIe Measurement Instruments

What Is a PXI Module?

A PXI module performs a specific measurement or test function inside a PXI system. The chassis provides power, cooling, backplane communication, clocks and trigger resources, while the controller runs the operating system, instrument drivers and test application.

Unlike most standalone instruments, PXI modules share a common chassis and can exchange triggers, reference clocks and measurement data through the backplane. This architecture supports compact automated systems containing multiple synchronized instruments.

A complete PXI test system normally includes:

• A compatible PXI or PXIe chassis
• An embedded PXI controller or remote-control interface
• PXI or PXIe measurement and control modules
• Terminal blocks, cables, RF connections or other signal accessories
• Supported NI drivers and application software

PXI Module Categories

How to Select the Right PXI Module

1. Define the Required Test Function

Begin with the signal or device requirement rather than a model number. Determine whether the system must measure voltage, current, resistance, RF signals, digital patterns, temperature, strain, vibration or frequency, or whether it must generate signals, provide power or route test connections.

This first decision identifies the correct module family. A general-purpose DAQ module, high-speed digitizer and dynamic signal module may all measure voltage, but they are designed for different bandwidth, noise, synchronization and signal-conditioning requirements.

2. Confirm PXI or PXI Express Compatibility

Traditional PXI modules use a PCI-based backplane, while PXI Express modules use PCI Express links. A PXIe chassis may contain PXIe peripheral slots, hybrid slots and system timing slots, each with different compatibility characteristics.

A hybrid slot can support compatible PXIe modules and selected hybrid-compatible PXI modules, but it does not support every traditional PXI product. Check the exact module connector and chassis slot map before ordering.

3. Define Channel Count and Signal Range

Calculate the total required channels, channels per module and expected future expansion. Also confirm maximum signal amplitude, common-mode voltage, input impedance, output drive and overload conditions.

Higher channel density can reduce chassis usage, but individually isolated or specialized channels may require more slots. Reserve enough chassis capacity for timing modules, switching, controllers and future additions.

4. Determine Accuracy and Resolution

ADC or DAC resolution alone does not determine measurement accuracy. Review gain error, offset, noise, drift, input range, calibration uncertainty and environmental conditions.

For production test, compare the complete measurement uncertainty with the DUT tolerance and required guard band. Selecting the smallest suitable range can improve effective resolution, but the range must still accommodate normal signals, offsets and expected overloads.

5. Match Sample Rate and Bandwidth

Choose sample rate and analog bandwidth according to the actual signal. Slowly changing temperature measurements have very different requirements from vibration, transient, RF or high-speed digital applications.

Maximum sample rate should not be treated as usable bandwidth. Analog front-end response, filtering, settling time, channel multiplexing and anti-alias characteristics must also be considered.

6. Decide Whether Simultaneous Sampling Is Required

Multiplexed modules measure channels sequentially and are suitable for many general-purpose applications. Simultaneous-sampling modules preserve timing and phase relationships between channels and are important for vibration, power, structural, acoustic and waveform-correlation measurements.

7. Review Isolation and Signal Conditioning

Industrial signals and sensor measurements may require channel isolation, bridge excitation, IEPE power, thermocouple cold-junction compensation, filtering or input protection. Confirm whether the selected PXI module includes the required conditioning or depends on an external accessory.

8. Calculate Data Throughput

For high-speed acquisition, estimate the continuous payload using the active channel count, sample rate and transferred bytes per sample. Include all modules that will operate simultaneously.

The complete data path includes the module interface, PXIe slot, chassis segment, controller connection, system memory, storage and application software. A bottleneck at any point can reduce sustainable performance.

9. Check Triggering and Synchronization

Determine whether modules must share a start trigger, sample clock, reference clock or timestamp. Instruments installed in the same chassis are not automatically synchronized unless the required timing routes are configured and supported.

Multichassis, phase-coherent RF and tightly correlated acquisition systems may require dedicated synchronization hardware and an engineered clock-and-trigger distribution plan.

10. Verify Power and Cooling

High-performance RF, FPGA, digital and storage modules can require more slot power and airflow than lower-speed instruments. Confirm per-slot cooling, total chassis power and the thermal effect of installing several high-power modules next to each other.

PXI Module, Chassis and Controller Compatibility

Software and Driver Support

NI PXI modules use different instrument drivers according to their function. Common examples include NI-DAQmx, NI-SCOPE, NI-DMM, NI-SWITCH, NI-DCPower, NI-FGEN, NI-RFSA, NI-RFSG, RFmx, NI-VISA and FlexRIO software.

NI Measurement & Automation Explorer is commonly used to identify installed hardware, run self-tests, inspect device configuration and manage calibration information. LabVIEW and TestStand can then be used to create measurement applications and automated test sequences.

Before purchasing hardware for an existing system, verify:

• Supported operating-system version
• Required NI driver and runtime versions
• LabVIEW or TestStand compatibility
• 32-bit or 64-bit application requirements
• Real-time and FPGA development-software requirements
• Third-party library and custom-code dependencies
• License requirements for analysis and measurement software

Representative NI PXI Modules

These models represent different PXI instrument families and are not direct alternatives. Final selection should be based on the required measurement function, specifications, chassis architecture and software environment.

Typical PXI Module Applications

• Automated production and functional test systems
• Semiconductor characterization and multisite device test
• RF, microwave, radar and wireless validation
• Automotive ECU and hardware-in-the-loop testing
• Aerospace, avionics and defense-system validation
• High-speed waveform acquisition and transient recording
• Electronic component and power-management testing
• Sound, vibration, structural and NVH measurement
• Industrial control and communication validation
• Scientific research and laboratory automation

Legacy PXI Module Replacement

Replacing a discontinued PXI or PXIe module requires more than matching its general function. A newer module may use a different connector, channel architecture, input range, bus interface, driver or calibration method.

Compare the following before approving a substitute:

• Complete model and part number
• PXI or PXI Express form factor
• Chassis slot and connector compatibility
• Channel count and electrical ranges
• Accuracy, resolution, sample rate and bandwidth
• Triggering and synchronization behavior
• Terminal block, cable and connector pinout
• Operating-system and driver compatibility
• Application API and existing software code
• Calibration and system-requalification requirements

For validated production equipment, sourcing the same module model may create less engineering risk than changing hardware and requalifying the complete test station.

PXI Module Procurement and RFQ Guide

For complete systems, send the full bill of materials so the modules, chassis, controller and accessories can be reviewed together. For pre-owned hardware, request device-recognition results, self-test information and functional channel testing appropriate to the module type.

Часто задаваемые вопросы

What is the difference between PXI and PXIe modules?

Traditional PXI modules communicate through a PCI-based backplane, while PXIe modules use PCI Express links for higher throughput. They also use different backplane connectors. Compatibility depends on the exact module and chassis slot type.

Can a PXI module be installed in a PXIe chassis?

Selected hybrid-compatible PXI modules can be installed in compatible PXIe hybrid slots. A standard PXIe peripheral slot does not automatically support traditional PXI modules. Check the chassis slot map and module connector before installation.

Can one PXI system use different types of modules?

Yes. A major advantage of PXI is the ability to combine acquisition, RF, switching, digital I/O, power, FPGA and communication instruments in one platform. The complete configuration must remain within the chassis compatibility, bandwidth, power and cooling limits.

How do I know which PXI module I need?

Start with the required test function, signal type, range, number of channels, accuracy, sample rate, bandwidth, isolation and timing requirements. Then confirm chassis, controller, driver and accessory compatibility.

Are terminal blocks and cables included with PXI modules?

Not necessarily. Many modules require separately ordered terminal blocks, connector blocks, RF cables, breakout cables or adapters. Check the complete signal path before ordering.

Can a newer PXI module directly replace a discontinued model?

Not always. Differences in connectors, ranges, channel architecture, drivers, timing and application APIs can prevent a direct replacement. Existing production systems may require software changes and requalification.

Do modules in the same chassis automatically synchronize?

No. The chassis provides clock and trigger resources, but the instruments must support the required routes and be configured correctly. Advanced or multichassis systems may require dedicated synchronization modules.

What limits PXIe data-streaming performance?

Performance can be limited by the module interface, selected slot, chassis segment, controller connection, system memory, storage or software. Sustainable throughput must be evaluated across the complete data path.

Recommended PXI Module Families

Related NI Measurement Platforms

Choose CompactDAQ systems for portable or distributed sensor acquisition, CompactRIO systems for embedded real-time and FPGA control, or PCI and USB instruments for direct computer-based measurement without a PXI chassis.

NI PXI Modules from PXISOURCE

PXISOURCE supports engineers, laboratories, system integrators and procurement teams with NI PXI module selection, chassis and controller compatibility review, accessory matching, current-product sourcing and legacy-system replacement. Send the required model, application, chassis configuration, software environment and preferred product condition for a technically matched quotation.