Data Acquisition

Data is everywhere. Data can inform decisions, prove research, and change our understanding. Too much data can be hard to sift through, but not enough data leaves holes in your understanding. As engineers, it is our responsibility to determine what data to collect, how to collect it, and what to do with this data.

Often, a data acquisition system has very specific timing requirements. We have worked with many systems and have applied strategies to ensure appropriate timing for each system. One of our challenges was working with multiple remote data acquisition units all communicating with a central data logging application. With no physical connection between DAQ hardware, we used a network time protocol (NTP) server to keep the system synchronized. In another complicated control system, there were hundreds of IO channels across multiple chassis that all needed to be synchronized within 1ms. The data also had to be read, analyzed, and a control response sent within 2ms. The solution we found was to use hardware timed single point sampling with shared sample triggers. The single point acquisition eliminated the data buffer and decreased latency so the control response was immediate. The hardware timing and shared triggers ensured synchronization which is not possible with software timed data acquisition. A shared clock ensured consistent sampling rate, but that was not enough. With external data loggers, everything needed a correlated timestamp. A card with GPS capabilities was used to correlate that time stamp. There are endless system needs and different strategies must be used for each individual project.