5 Ways High-Density PXI Waveform Generators Improve HIL Validation

You're at a test bench late on a Thursday afternoon, building a hardware-in-the-loop (HIL) system for a new industrial controller. The test plan requires you to simulate high-voltage transients within typical sensor signals, so you route the signals, configure the software, and run the sequence. However, the test fails. The standard function generator card in your PXI chassis peaks at ±10 Volts, but the real-world sensor requires a ±25 Volt sweep to trigger the correct fault codes. You're now stuck with a hardware limitation that stops the entire validation process.

This scenario illustrates a common bottleneck in hardware validation. Standard function generators and generic analog output cards work well for simple tasks, but fall short when a test requires high voltage, high channel density, and phase-continuous frequency control. Engineers need tools that fit specific, demanding criteria without forcing them to rebuild their entire test architecture.

This article examines the capabilities of modules beyond basic function generators, focusing on solutions that deliver reliable long-term performance.

Key Considerations to Improve HIL Validation

• Wide Output Range: Modern device testing demands a wider output range than older systems. Having a broader output-voltage capability eliminates the need for additional signal conditioning and the associated costs, space requirements, and extra wiring. A wide output range also delivers the flexibility to handle a diverse set of devices under test (DUTs), including industrial accelerometers and heavy-duty machine sensors that operate well above the standard ±10 Volt limit.
• Frequency Range: A higher frequency range lets a single solution simulate everything from low-frequency signals, such as those from a strain gauge, to high-frequency transients from an accelerometer, as well as most audio frequencies. This breadth enables a wide variety of testing scenarios without the need to switch hardware between tests.
• Precise Control: Preventing unrealistic faults and eliminating gaps or inconsistencies in simulated signals can only be achieved through precise signal control. Techniques like Direct Digital Synthesis enable instantaneous, software-controlled frequency adjustments with continuous phase behavior, critical when testing sensitive analog inputs, where a single signal skip or jump can trigger false errors.
• Waveform Versatility: The ability to replicate complex waveform environments lets engineers drive different sensor types across multiple channels in a single test run, which is essential for accurate simulation in multi-sensor environments. With independent control per channel, every channel can generate a completely different signal at the same time, whether that's a continuous sine wave, triangle, pulse, or user-defined arbitrary waveform. When multiple channels run periodic waveforms at the same frequency, a single command can align their phases.
• Precise Timing and Synchronization: Synchronizing the stimulus with the broader test system keeps all instruments working in step. Trigger functions allow events from other instruments to initiate waveform generation or sweeps, ensuring coordinated operation across the entire setup. Engineers can also apply a DC offset and use flexible frequency-sweep capabilities to simulate dynamic, real-world conditions.

Our Waveform Generator: 41/43-625

The 41-625 (PXI) and 43-625 (PXIe) waveform generators offer a practical solution for engineers building functional test and hardware-in-the-loop systems. These modules offer a wider output and frequency range, precise control, waveform versatility, and the timing and synchronization needed in today’s HIL systems. Both versions occupy a single chassis slot and deliver high channel density, with configurations of 8, 16, 24, or 32 channels. This density allows test engineers to replace racks of lower-density bench instruments with a compact, integrated solution.

Real-World Applications

These advanced specifications translate directly to field applications. A major use case involves simulating accelerometers throughout the entire product lifecycle, including lab design validation, automated production testing on the manufacturing floor, and field maintenance checkouts. Our high channel density and wide voltage range enable simultaneous simulation of multiple sensors, accurately stressing the device under test as it would in the real world.

PXI Module Comparison

The table below highlights how Pickering modules compare to key competitors across critical performance and integration factors.

Our 41/43–625 waveform generator stands apart for its combination of higher voltage, a wide range of variants to fit specific applications, and formats that support PXI, PXIe, and Pickering LXI/USB test systems. And, unlike ground-referenced analog output cards, our waveform generator’s isolated-channel architecture supports accurate sensor-level simulation in HIL and functional test systems. Lastly, as always, we offer a 3-year warranty and guaranteed long-term support (typically 15-20 years).

Elevating Your Hardware Validation Strategy

In conclusion, advanced test systems require hardware that eliminates bottlenecks and provides reliable, repeatable data. Our 41/43-625 series function generators deliver on all five ways to improve HIL validation, including the high voltage, channel density, and precise control necessary for complex functional testing, while seamlessly integrating into existing platforms and offering the long-term support required by risk-averse industries.

To improve your testing capabilities and reduce cycle times, explore the full specifications of the 41–625 and 43–625 series.

Talk to Pickering about HIL sensor simulation, waveform generation, or custom signal paths.

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