Ep 2: Core Sensors in Industrial Automation

From monitoring pressure in oil pipelines to keeping pH levels balanced in water treatment, sensors are the backbone of automation. These devices allow systems to measure, react, and run efficiently 24/7 without constant human input. Not all sensors are the same—each is designed for a specific purpose. Knowing how they work helps engineers design safer, more reliable systems. 

What Are Sensors? 

A sensor is a device that detects a physical or chemical change and converts it into a measurable signal. Sensors are essential for: 

Temperature Sensors 

Pressure Sensors 

Flow Sensors 

Level Sensors 

Analytical Sensors 

Summary 

Each sensor type has its own principle, features, and ideal applications. The right choice depends on: 

Think of sensors as the eyes and ears of automation, feeding data to controllers, which then direct actuators to take action. From chemical plants to food production to wastewater facilities, sensors form the foundation of modern automation which keeps processes running smoothly, safely, and efficiently.

Trancript from Video:

[0m:00s] Hey, it’s Mitchell. Welcome to another video in the RSP Education Series. Have you ever wondered how massive factories, treatment plants, or high-tech labs always seem to know exactly what’s happening at all times? From monitoring pressure in oil pipelines to keeping pH levels just right in water treatment to controlling temperature in pharmaceutical production—it all comes down to one thing: sensors. These tiny devices are fundamental to automation. They’re the reason processes run smoothly, safely, and efficiently 24/7. But not all sensors are created equal. Each one works differently and solves a specific problem. Knowing how they work is what turns a good engineer into a great one. In this video, we’re diving into the core sensor types used in industrial automation and exactly how each one works. By the end, you’ll not only understand the tech but also be able to apply it with confidence in the real world.

[1m:14s] Let’s start with the basics—what are sensors? They’re devices that detect physical or chemical changes and then convert those changes into measurable signals. They’re critical for process control, safety, and efficiency, especially in industries like oil and gas, pharmaceuticals, food and beverage, and water treatment. One of the most common types is the temperature sensor, which measures heat energy in a process. There are three main kinds: RTDs, thermocouples, and infrared sensors. RTDs, or resistance temperature detectors, change resistance predictably with temperature and are highly accurate and stable. You’ll find them in lab equipment and industrial ovens. Thermocouples generate voltage using two dissimilar metals and are perfect for high-temperature applications like furnaces or engines. Infrared sensors, also called non-contact sensors, detect thermal radiation and are ideal for moving or hazardous objects in environments like metalworking and food processing.

[2m:54s] Next are pressure sensors, which measure the force exerted by gases or liquids in a system. The three main types include pressure gauges, pressure transmitters, and pressure switches. Pressure gauges are mechanical and use a Bourdon tube or diaphragm that moves a needle as pressure changes. They’re simple, reliable, and don’t need power—great for tanks or air systems. Pressure transmitters convert pressure into an electrical signal, making them excellent for remote monitoring and process control. Pressure switches activate an electrical contact when pressure reaches a set point, making them common in safety cutoffs and alarms like those in boilers or hydraulic systems. Flow sensors are another important category, used to measure how fast a liquid or gas moves through a pipe. Magnetic flow meters (mag meters) work on Faraday’s law and have no moving parts, making them great for conductive fluids like water. Ultrasonic flow meters measure time differences in ultrasonic waves, while Coriolis flow meters use vibration to measure mass flow and density with extreme accuracy.

[4m:57s] Level sensors are designed to detect how high liquids or solids are in a tank. Radar level sensors send out microwave pulses that reflect off the material’s surface, providing accurate readings even in harsh environments like chemical storage or bulk solids. Ultrasonic level sensors use sound waves instead of microwaves and are a more affordable, non-contact option for tanks and silos. Then we have analytical sensors, which measure chemical properties of liquids. pH sensors measure hydrogen ion activity to ensure proper chemical balance in processes like water treatment or brewing. Conductivity sensors measure how well a solution conducts electricity based on ion concentration, helping determine purity or salinity—often used in desalination systems or pharmaceuticals.

[6m:15s] To summarize, each sensor type has its own unique working principle and ideal application. The right choice depends on the required accuracy, environment, and purpose. Industrial automation depends on these sensors—they make real-time monitoring and control possible. We’ve covered temperature, pressure, flow, level, and analytical sensors, how each one works, and where you’ll find them in the real world. Whether it’s a chemical plant, food production line, or wastewater facility, sensors are the backbone of any automated system. They give us the eyes, ears, and touch we need to monitor and control everything around us. For hundreds of thousands of industrial automation products, visit our website at rpsupply.com—the internet’s top source for industrial hardware.