By Maurizio Di Paolo Emilio
Data acquisition is a necessity, which is why data acquisition systems and software applications are essential tools in a variety of fields. For instance, research scientists rely on data acquisition tools for testing and measuring their laboratory-based projects. Therefore, as a data acquisition system designer, you must have an in-depth understanding of each part of the systems and programs you create.
I mainly design data acquisition software for physics-related experiments and industrial applications. Today’s complicated physics experiments require highly complex data acquisition systems and software that are capable of managing large amounts of information. Many of the systems require high-speed connections and digital recording. And they must be reconfigurable. Signals that are hard to characterize and analyze with a real-time display are evaluated in terms of high frequencies, large dynamic range, and gradual changes.
Data acquisition software is typically available in a text-based user interface (TUI) that comprises an ASCII configuration file and a graphic user interface (GUI), which are generally available with any web browser. Both interfaces enable data acquisition system management and customization, and you don’t need to recompile the sources. This means even inexperienced programmers can have full acquisition control.
Well-designed data acquisition and control software should be able to quickly recover from instrumentation failures and power outages without losing any data. Data acquisition software must provide a high-level language for algorithm design. Moreover, it requires data-archiving capability for verifying data integrity.
You have many data acquisition software options. An example is programmable software that uses a language such as C. Other software and data acquisition software packages enable you to design the custom instrumentation suited for specific applications (e.g., National Instruments’s LabVIEW and MathWorks’s MATLAB).
In addition to data acquisition software design, I’ve also been developing embedded data acquisition systems with open-source software to manage user-developed applications. The idea is to have credit-card-sized embedded data acquisition systems managing industrial systems using open-source software written in C. I’m using an ARM processor that will give me the ability to add small boards for specific applications (e.g., a board to manage data transmission via Wi-Fi or GSM).
A data acquisition system’s complexity tends to increase with the number of physical properties it must measure. Resolution and accuracy requirements also affect a system’s complexity. To eliminate cabling and provide for more modularity, you can combine data acquisition capabilities and signal conditioning in one device.
Recent developments in the field of fiber-optic communications have shown longer data acquisition transmission distances can cause errors. Electrical isolation is also an important topic. The goal is to eliminate ground loops (common problems with single-ended measurements) in terms of accuracy and protection from voltage spikes.
During the last year, some new technological developments have proven beneficial to the overall efficacy of data acquisition applications. For instance, advances in USB technology have made data acquisition and storage simpler and more efficient than ever (think “plug and play”). Advances in wireless technology have also made data transmission faster and more secure. This means improved data acquisition system and software technologies will also figure prominently in smartphone design and usage.
If you look to the future, consumer demand for mobile computing systems will only increase, and this will require tablet computers to feature improved data acquisition and storage capabilities. Having the ability to transmit, receive, and store larger amounts of data with tablets will become increasingly important to consumers as time goes on. There are three main things to consider when creating a data acquisition-related application for a tablet. Hardware connectivity: Tablets have few control options (e.g., Wi-Fi and Bluetooth). Program language support: Many tablets support Android apps created in Java. Device driver availability: Device drivers permit a high-level mode to easily and reliably execute a data acquisition board’s functionality. C and LabVIEW are not supported by Android or Apple’s iOS. USB, a common DAQ bus, is available in a set of tablets. In the other case, an adapter is required. In these instances, moving a possible data acquisition system to a tablet requires extra attention.
For all of the aforementioned reasons, I think field-programmable arrays (FPGAs) will figure prominently in the evolution of data acquisition system technology. The flexibility of FPGAs makes them ideal for custom data acquisition systems and embedded applications.