The right data acquisition system for vehicle testing is the one sized to your sensors, frequency content, test duration and operating environment, not the one with the longest spec sheet. Start by listing what you need to measure and how fast it changes. Channel count, signal conditioning, sample rate, CAN integration, ruggedness and software then narrow the field quickly.
Start with the test, not the hardware
A clear test definition prevents both overbuying and discovering a missing capability halfway through a program. Before comparing systems, answer these questions:
- What will you measure? Strain, load, displacement, acceleration, sound, temperature, pressure, speed, vehicle network data, position.
- What frequency range matters? Durability loads, ride motion and powertrain noise live in very different bands.
- How long will you record? Minutes on a proving ground or weeks of unattended customer-usage data.
- Where will the hardware live? A lab bench, a passenger seat, a trunk, or a chassis rail exposed to heat, water and vibration.
- Where will the data go? Durability software, NVH analysis, road simulators or custom scripts.
How many channels do you need?
Count every sensor channel, add vehicle network and position data, then leave real headroom for the channels engineers inevitably request mid-program.
Architecture matters as much as the total:
- Centralized systems keep all inputs in one chassis. They’re simple, but long sensor cables run across the vehicle.
- Distributed systems place modules near sensor clusters and link them with digital cables, which cuts wiring and noise pickup.
Mars Labs’ Titan platform illustrates the distributed approach. Each input module provides 16 analog channels, and CPU channel expanders link modules over a single CAT6 cable that carries power, communication and synchronization. The CPU04, CPU08 and CPU12 support 64, 128 and 192 analog channels, and the CPX08 links three 8-port CPUs for up to 384. Prosig’s DATS family scales from the 4-input DATS-solo and 24-input DATS-P8012 to the 32-input DATS-tetrad and the 96-input DATS-hyper12, which stacks past 1,000 channels.
What signal conditioning does each sensor need?
Every sensor type needs specific excitation, amplification or compensation, and mismatched conditioning is a common source of bad data.
| Sensor | Conditioning required | Practical notes |
|---|---|---|
| Strain gauges and load cells | Bridge excitation, amplification, bridge completion for quarter and half bridges, shunt calibration | Check excitation voltage against gauge resistance and self-heating |
| IEPE (ICP) accelerometers and microphones | Constant-current supply, AC coupling | Verify current setting and sensor bias voltage |
| Thermocouples | Cold-junction compensation, linearization | Use the correct type (J, K, T) and connector material |
| Voltage outputs | Input range and isolation | Watch for ground loops on vehicle power |
| Tachometer and encoder signals | Counter or timer inputs | Needed for order tracking and speed-based analysis |
| AC LVDTs | Excitation and demodulation | Or use DC LVDTs with voltage or 4–20 mA outputs |
Universal inputs simplify this. Mars Labs’ BMS16 and CMS16 modules configure each channel in software for full, half or quarter bridge strain with 350 Ω completion, 2.5 mA IEPE, ±32 V voltage, J, K or T thermocouples, and tach or totalizer signals. The BMS16 offers programmable per-channel excitation from 2 to 11.5 V, and both modules use 24-bit converters. For conditioned sensors such as load cells and torque sensors, confirm the output type before you allocate channels.
How fast should you sample?
Sample fast enough to capture the highest frequency you care about without aliasing. The theoretical minimum is twice the highest frequency (Nyquist), but real anti-aliasing filters need room, so frequency-domain work commonly uses 2.56 times the analysis bandwidth. Time-domain peak measurements need considerably more, often ten times the highest frequency of interest.
| Test type | Typical signals | Frequency content | Practical notes |
|---|---|---|---|
| Durability and road-load | Strain, wheel forces, suspension displacement | Mostly low frequency | Long recordings; RPC III export for road simulators |
| Ride and handling | Acceleration, IMU, GPS, steering | Low frequency | Tight sync with CAN and GPS |
| Thermal and powertrain surveys | Thermocouples, pressures, CAN | Very low for temperatures | High thermocouple channel counts |
| NVH and acoustics | Microphones, accelerometers, tach | Into the audio range | Sampling around 51.2 kHz covers 20 kHz |
| Impact and crash | High-g acceleration, load | Up to several kHz | Filtering per SAE J211 channel classes |
Mixed-rate capability helps: record NVH channels fast and thermocouples slowly in the same test to keep file sizes manageable. The Mars Labs CMS16 reaches 60,000 samples per second per channel in high-speed mode, while the BMS16 runs up to 10,000 samples per second per channel.
How do you synchronize CAN bus, GPS and analog data?
Vehicle network data explains the conditions behind every measurement, so it should share a timebase with the analog channels. Key protocols include:
- CAN 2.0A/B and CAN FD for passenger vehicle networks. Decoding typically uses a database (DBC) file from the vehicle or ECU supplier.
- SAE J1939 for heavy-duty trucks, buses and off-highway equipment.
- ISO 15765 and SAE J1979 (OBD-II) for diagnostic parameters.
Mars Labs’ EDP09 digital pod adds six CAN or CAN FD inputs with J1939 and ISO 15765 decoding, Kistler and Michigan Scientific wheel force transducer protocols, GPS, IMU and quadrature encoder inputs. Mars Labs states digital data is synchronized with analog channels to within one millisecond or one scan period. Prosig’s palm-sized, Kvaser-based DATS-CANetic logs CAN 2.0A/B, CAN FD and OBD-II parameters directly into DATS alongside vibration channels.
How rugged does a vehicle DAQ need to be?
In-vehicle hardware must survive the vehicle’s electrical system and environment. Look at:
- Power input. Wide DC input handles cranking dips and charging spikes. Titan modules accept 11–32 VDC and draw about 3 W before sensor loads.
- Stand-alone recording. Unattended tests shouldn’t depend on a laptop. Titan modules record to on-board SD cards; the CMS16 ships with 32 GB.
- Power interruption handling, such as a battery backup accessory.
- Connectors and cabling that resist vibration and moisture. The Titan BSG16 uses Bendix connectors.
- Operator feedback. A simple in-vehicle display, like Titan’s PTC04, shows record status without a PC.
- Environmental ratings. Confirm temperature, shock and ingress ratings on the datasheet for your mounting location.
What should you look for in DAQ software?
Software determines how quickly raw data becomes engineering results. Evaluate setup, live display and analysis workflow:
- Sensor database and calibration tools, including bridge balance and shunt calibration.
- Export formats. Titan Control Software exports RPC III, MATLAB, HDF5, WAV, CSV and TSV, and offers an API for custom integration.
- Analysis depth. Prosig DATS provides modules for NVH, rotating machinery and order analysis, modal testing, fatigue and durability, and human response to vibration to ISO 2631 and ISO 5349.
- Automation. DATS worksheets let engineers build repeatable analysis routines without writing code.
Mars Labs and Prosig can complement each other on the same program: Titan hardware for high-channel-count, in-vehicle durability recording, and DATS for NVH acquisition and analysis. See noise and vibration analysis for more on the analysis side.
Vehicle testing across the Southeast
The Southeast is home to a dense automotive manufacturing base, with assembly plants in Vance, Lincoln and Montgomery, Alabama; West Point, Georgia; Spartanburg, South Carolina; Smyrna and Chattanooga, Tennessee; and Ford’s BlueOval City project in Stanton, Tennessee. Supplier plants, university research programs and defense vehicle work add to the demand for durability, NVH and validation testing close to where vehicles are built.
Local DAQ application support
Vaughn Associates represents Mars Labs and Prosig across all Vaughn territories. Our sales engineers can help you build a channel list, match signal conditioning to your sensors, plan CAN integration and choose the right mix of hardware and software, then coordinate quotes directly with the manufacturers.
Explore data acquisition systems, the Mars Labs and Prosig line pages, find your area manager on the territories map, or request application help.
