First time visiting our Blog? Perhaps you entered a search term in Google and stumbled across the site? If so, you might be asking yourself “What is all this ‘data acquisition’ stuff?”
Data Acquisition Major Selection Criteria
The process begins with sensors (strain gauges, thermocouples, etc.). Electrical signals from the sensors are fed into data acquisition instruments, which digitize these analog signals into their computer-compatible equivalent. From there, the power of your PC goes to work to explore recorded data in a myriad of ways quickly and efficiently. So, throw away your clipboard and read on.
Match Data Acquisition and Signal Source Ranges Carefully
Carefully choose your data acquisition system to ensure that it supports a measurement range that is consistent with your signal sources. For example, the most frequently measured signal source combination is voltage and temperature. So, products like these may be appropriate. If you need to measure more signal types, products that support a deeper selection of signal types can be considered.
Does Your Data Acquisition System Need Isolation?
Also, pay strict attention to the need for isolation. If you’re not sure if you need that feature, this application note should help. All things equal, this decision makes the difference between a successful measurement and one that is noisy, grossly inaccurate, or permanently damages your data acquisition system.
Data Acquisition Sample Rate Considerations
Like isolation, sample rate selection can make or break a measurement. This metric expresses either a sampling interval in a unit of time, or a sampling rate in Hertz. For example, a sampling interval of 1 mS means that the instrument samples once every millisecond, or 1000 times per second. The same instrument can then be speced to sample at a rate of 1 kHz. You can easily transition from sample rates and intervals by taking the reciprocal of the stated value. Continuing with the same example, a speced sample rate of 1 kHz means one sample every 1/1000 seconds, or one millisecond. Likewise, a sample interval spec of 0.001 S means 1/0.001, or a sampling rate of 1,000 Hz (1 kHz.)
Regardless of whether you view sampling as a rate or an interval, take care to choose the instrument’s spec to match the fastest expected excursion of the signals you want to measure. If instrument sample rate under performs versus signal excursion rates you risk generating aliased data that’s disastrous for subsequent analysis and interpretation. By the same token, who needs to sample temperature data at a rate of 10 kHz (one every 100 µS?) We’ve published a detailed application note about sample rate considerations, which you can find here.
Is Yours a Stand-alone or PC-connected Data Acquisition Requirement?
Do you need to cut the cord? All data acquisition systems provide some sort of PC interface. USB and Ethernet are the most prevalent. PC-connected instruments need to be connected to a PC to acquire data. If you disconnect the cable, you terminate the data acquisition session, usually without recovery unless you reinitialize the system. This approach is fine for some applications where the system under test is accessible and perhaps needs adjustments in real time. However, unattended and longer term measurements might benefit from the ability to disconnect the data acquisition system from a PC and operate autonomously. The term “stand-alone” refers to this approach to data acquisition. While these systems are usually configured using a PC over an Ethernet or USB interface, once set up the connection is removed and the instrument is placed anywhere a measurement is required without the PC. Acquired data is recorded to usually non-volatile memory for subsequent upload to a PC for analysis and interpretation. DATAQ Instruments offers a range of instruments, many of which support either PC-connected or stand-alone operations, or both. Visit our primary data acquisition selection page that offers filters to narrow the choice of instruments based upon connection criteria and more.
Finally, Why is Data Acquisition Important?
Whether you realize it or not, data acquisition plays a critical role in fields such as life science research, civil engineering and industrial maintenance, to name few. Walk into any steel mill, public utility or research laboratory in the world and you’ll find some sort of data acquisition device, quietly monitoring one parameter or another. The data gathered can be used to improve efficiency, ensure reliability or to make certain that machinery is operating safely. Recorded data is retrieved to ensure that the system under test performed as expected, and to identify problem areas that need adjustments. Real time data acquisition systems generate and display measurements without delay. Imagine a drive system or an engine performance measurement where adjustments to the system provide instantaneous feedback, and thus allow a technician to quickly reach optimal performance without trial and error. In this sense, here are just a handful of specific applications where DATAQ Instruments’ data acquisition systems provide a measurement edge:
- Monitor the integrity of the I-35 Mississippi River Bridge.
- Studies to protect grape vines from disease.
- Ensure safe operation of the retractable roof over SAFECO field
- Measure implant adhesive effectiveness
- Variable speed drive measurements in rolling and paper mills
- Electric outboard trolling motor qualification
- Automobile moon roof qualification
And so many more limited only by your imagination.
Let’s Talk About Your Specific Data Acquisition Needs!
Still not sure? Contact us and speak directly to an application specialist who’s trained to quickly identify a range of data acquisition products that satisfy your specific expectations and requirements.