What is a data acquisition system?
A data acquisition (DAQ) system is the hardware and software that measures signals from sensors, digitizes them on a common timebase and stores them for analysis. In test engineering, a DAQ system is the bridge between the physical event, such as a pothole strike, a rocket motor firing or a wing bending, and the data engineers use to make design decisions.
Test DAQ differs from plant control I/O. It samples far faster, synchronizes many channels precisely, conditions sensitive sensors like strain gauges and accelerometers, and often has to survive vibration, temperature extremes and vehicle power in the field.
How data acquisition works
Every channel passes through the same basic chain:
- Sensor excitation: Bridge sensors need a stable excitation voltage, and IEPE accelerometers need constant-current power.
- Conditioning: Amplification, bridge completion, offset balance and anti-alias filtering prepare the signal for conversion.
- Conversion: An analog-to-digital converter, typically 24-bit in modern test systems, samples each channel at a set rate.
- Synchronization: Channels, modules and digital sources such as CAN and GPS share a timebase, so events line up across the dataset.
- Storage and software: Data goes to a PC, internal memory or SD card, then to analysis tools in standard formats.
| Signal type | Conditioning required | Typical sample rate |
|---|---|---|
| Strain gauge and load cell | Excitation, bridge completion, shunt calibration | Hundreds to thousands per second |
| IEPE accelerometer and microphone | Constant-current supply, AC coupling | Thousands to tens of thousands per second |
| Thermocouple | Cold-junction compensation, filtering | A few to tens per second |
| Voltage and 4–20 mA | Scaling, isolation | Application-dependent |
| Tachometer or encoder | Pulse counting, speed calculation | Event-based |
| CAN, GPS and IMU | Protocol decoding, time alignment | Message-based |
The practical challenge is combining all of these in one synchronized recording without a tangle of separate instruments. Universal-input modules and distributed expanders connected by a single cable for power, data and sync simplify large installations.
Common applications
- Military and heavy vehicle testing: Army ground vehicle programs that need hundreds of strain and acceleration channels, relevant to Huntsville’s defense test community.
- Automotive durability and NVH: road-load data acquisition, fatigue testing and ride quality work for the Southeast’s assembly plants and suppliers.
- Aerospace structural testing: strain surveys and load monitoring on airframes and space hardware.
- Rail, marine and transportation: in-service measurement on railcars and boats.
- University research: flexible, multi-sensor systems for student and faculty test programs.
Choosing the right data acquisition system
Buy for the test program, not the brochure’s maximum channel count. Start with an inventory of sensors, then decide where the system will operate. A durability test that runs for weeks unattended in a truck has very different needs from a lab modal survey. Pay close attention to strain conditioning, synchronization across modules and file formats. Losing time converting data or re-running tests because of a clipping or aliasing error costs more than hardware.
Manufacturers we represent for data acquisition
Mars Labs of Laurel, Maryland, has built rugged DAQ systems since 1999. Its US-built Titan platform uses 16-channel universal-input modules that record stand-alone to SD cards or combine through CAT6-connected channel expanders into synchronized systems of hundreds of channels. Mars Labs has supported durability and NVH programs for Ford and large-channel-count systems for the US Army.
Prosig pairs its DATS acquisition hardware, from the four-channel DATS-solo to the stackable DATS-hyper12, with analysis software for NVH, modal, fatigue and rotating machinery work.
Get local application support
Our Huntsville-based area managers focus on aerospace, defense and automotive test. We can help size channel counts, plan sensors and cabling, and set up demonstrations. Visit engineering support, request a quote, or find your area manager on the territories page.
