As human beings, we have always been defined by our ability to sense—hear, speak, feel, see, taste and smell, to name a few. In industry, we need to have the ability to use use all of these senses, as well as gather other dimensional characteristics such as position, temperature and speed, for example.

Voice-activated control has been floated on the plant floor but has drawbacks that may be obvious.

Sensor technology has progressed in the 2000s with voracious speed and capability. Yet the pushbutton remains as one of the mainstays since it allows interfacing of operations to the control.

Automatic control requires the ability to cover all bases to sense all things process or machine control. That includes manual interfacing, as well as process/machine sensing.

The main advancements that we have seen in the overall system can be classified as edge computing, Industrial Internet of Things (IIoT), wireless sensing and energy harvesting.

Small single-board computers operating at the edge can support various sensing technologies, which need to be able to prove and execute algorithms to push data to the cloud. Those systems typically would not have a large I/O count but may need specialized I/O to measure and detect variables in the monitored process. It’s just not about limit switches and pushbuttons anymore.

Some instrumentation in the field used to be only found in a lab somewhere, such as chemical analysis equipment. Near-infrared (NIR) spectroscopy can be mounted in situ to constantly monitor physical properties in process liquids. I am of the opinion that whatever we need to accomplish in the field can be done using current sensor technology.

One of the key advancements is the ability to have these digital sensors as part of the intrinsic solution for automatic system control. They can be networked using standard industrial protocols or directly connected using standard instrumentation connectivity.

One of the huge benefits is having this data available. In so many cases, testing is done after the process is complete, and only then is a problem discovered in the process, which is altered after the fact.

To be able to have real-time data to affect the process and/or machine control on the floor or at the edge is invaluable.

Using this data for online dynamic changes to the process can only provide for better control, higher productivity and less unplanned downtime.

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Sensors provide a microscope into the operation of the process or machine. It gives us feedback on mechanical movement and allows the operators to better understand how the process is running, assuming there is an operator. Some automated systems are being monitored and adjusted by an operator sitting in a control room looking at supervisory control and data acquisition (SCADA) screens.

Take a nuclear reactor system, for example. There is no one in the system; all monitoring is remote. Machine control, however, would probably have an operator present monitoring the physicality of the output of the machine.

Vision systems could be employed to do that monitoring. However, should the resulting output not be to spec, the machine could be experiencing a symptom that is not being monitored, such as sound.

So many operators know that a machine is running at peak performance by the sounds it makes at the various stages of the process. I have seen an operator determine that the hydraulic pressure was marginally low due to the sound that the die closing made. It just doesn’t sound the same.

Can or should sensors replace all aspects of machine and process control? It depends. In an oil refinery, the level of sensory feedback is at the highest level, and yet we still have accidents and fires.

The BP-owned Texas City Refinery fire was caused by an overfilling of a splitter tower, and it overheated. Sensors did not detect this scenario creating the accident. Did no one think that this would happen? Were sensors even present?

Applying sensors has many facets to it. Use for control in positioning and mechanical movement is as old as the hills. Sensors used for process/machine safety only operate when something goes wrong. Both are equally important, and the advancement in the application of sensors should leave nothing unsensed.

There’s no excuse for not sensing anything these days, and the argument of cost should refer to the memory of Texas City. One of the missing constituents in project design in some cases are the functional requirements documents. This approach to automation design should include all facets of sensor applications, and, with the technology where it is, we can do it all.

Go forth and sense.