Input transducers convert pressure, temperature, moisture, parts per million, force, whatever you wish to monitor in the world, into electrical signals. These signals take the form of 4-20 mA or 0-10 V. For instance, a pressure transducer would sense, via a diaphragm movement, go through a strain gauge, and then use an amplifier to generate a 4-20 mA output (Figure 1).

The signal is created when a physical stimulus produces a correlated, proportional electrical output. Then the signal will traverse the airways and find its way inputted into a PLC and likely a PID loop. If not, maybe it’s just going to get used in a historian for trending so that people can use the data to make decisions.

Output transducers are known as actuators. The actuator converts an electrical signal into physical action. Motors turn on when levels get too low or too high. Blow off valves open when pressures are greater than the norm. Alarms sound when a gas is monitored in the air. Actuators are associated with action. The thought process is that sensors gather information, and actuators influence the change of environment. Both sensors and actuators are needed for a control loop to function.

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A wireless node is also required. Transducer analog signals are suitable for short distances but are not compatible with wireless digital communications. Wireless nodes convert analog signals to digital signals via conditioning and scaling, using an analog to digital component, and some kind of packaging that fits a usable wireless protocol. Common wireless protocols are Wi-Fi, Bluetooth, Zigbee and LoRa. Sensors send data to the node, the node converts the signal, and then the signal is sent to a gateway or cloud to be monitored, analyzed or stored.

If this conversion process did not occur, wireless monitoring of physical conditions would not be possible. Transducers are essential components in wireless environments. Wireless systems allow seamless interaction between physical environments and digital systems. Input transducers (sensors) capture real-world data, while output transducers (actuators) translate digital commands into physical action. However, because many traditional transducers produce analog signals, a wireless node or transmitter is necessary to convert these signals into digital form. This conversion allows the data to be transmitted, processed and utilized within wireless networks, making modern monitoring and control systems more efficient, scalable and flexible. The ability to be flexible is what makes wireless a viable avenue in today’s operational technology world.

One example of a real-time wireless network that provided operational feedback to a distributed control system (DCS) is using temperature monitoring of a pyro processing system using a rotary kiln. Cement kilns are long, large and outside, so they meet the challenging environment criteria. However, wireless monitoring allows instant feedback, and a gateway allows DCS interface to the wireless network. This means alarming can occur in real time, so that if there are limited operators in the control room, they don’t have to walk a route to get information. For this reason, wireless technologies are a great addition to the operational technology environment (Figure 2).