Complexity in the controls world is expanding exponentially. The amount of data necessary to describe the real world is staggering when fully considered. Sensors and feedback devices of every imaginable type are providing many orders of magnitude of increased resolution to allow improved control over processes in all industries.
The rotary encoder that was typically 2,048 pulses per revolution is being gradually replaced by devices that produce 2 million pulses per revolution. 1,000 times increase in resolution. Video display technology that was previously limited to 525 x 200 are commonly 1920 x 1080 today. With 25 frame per seconds video rates, 50 megabits per second for video data is routine. This makes Gigahertz Ethernet an absolute necessity to support today’s requirements, not to mention what it will take to support bandwidth needs in the future.
Edge computing offers a strategy that will help manage the explosion of data. In the presence of very inexpensive processing power, it is possible to put System on Chip (SOC) devices out near the sensing and implement programming the processes the local data. This architectural strategy allows local processing of large streams of data and determine what data is meaningful and what isn’t. In the audio realm oversampling of 128 khz is used routinely to refine real world audio data that is filtered and stored at no more than 20 kHz. This allows the data stream to be correlated eliminating dropouts and discontinuities that occur in the process of digital sampling. The resulting stream can be stored in a compressed file using conventional algorithms.
Using the edge computing strategy it becomes possible to use significant amounts of data to provide details of processes that are normally not available to lower resolution systems. There are electrical phenomena such as 60 Hertz AC voltages and currents that are easily observed at low sampling rates. In fact, the sampling theorem would suggest that a 600 Hertz sampling rate is sufficient to model the waveform. That is true within the limitations of the 60 cycle waveform. Introducing variable frequency drives and other loads can create complex harmonics that are not subject to analysis at 600 Hz. System analysis has shown that 12kHz is needed to capture the complex harmonics of modern electrical systems.
Better data leads to better decision making, and local processing can be used to reduce data to manageable levels. The future of control is alive and well. Complexity is not a threat, but a challenge to create better systems.