Why sensors are key to industrial automation

Automation can be applied to a wide range of industries, such as manufacturing, transportation and energy production, to improve productivity, quality, and efficiency. The tasks that can be automated include assembly and packaging of products via robotics, materials handling systems, including conveyor belts and automated guided vehicles, 3D printing, monitoring production lines, controlling machinery and performing quality control checks.

To keep the automated processes operational, a number of different technologies are used, including sensors. Sensors play a crucial role by detecting and measuring a variety of parameters such as temperature, pressure, humidity, flow rate, motion, and position. They convert physical signals into electric signals and provide information in real-time to the control system, thereby making production intelligent and automated. Various technologies are used to achieve the desired output including inductive, magneto-resistive, ultrasonic and capacitive.

The function of sensors in automation applications

Sensors provide the means for automated systems to perceive and respond to changes in their environment. Their function may include:

1. Control

Monitoring the parameters of the manufacturing process such as temperature, pressure and humidity, and providing feedback to the control system to enable adjustments to be made. For example, in a temperature control system a sensor might detect the temperature of a room and send this information to a controller which then adjusts the output of a heating or cooling system to maintain the desired level.

2. Efficiency

Optimising the performance of machines and processes through measurement of factors such as speed, temperature, and pressure to help reduce waste, energy consumption and downtime. Automation can perform repetitive tasks at a much faster rate than humans, which can reduce cycle time and increase production output. It can also help reduce the risk of workplace accidents by taking over high-risk tasks that can lead to injury.

3. Safety

Detection of hazardous conditions including high temperatures, toxic gases or excessive pressure which will then trigger an alarm or shutdown process. Proximity sensors, for instance, can be used to detect the presence of objects or people in hazardous areas.

4. Quality control

Measuring size, shape and colour, detecting defects or variations and alerting the control system to take corrective action. Automation can ensure that products are manufactured to consistent and precise specifications, and analysis of the data collected on production processes can help identify trends that may indicate quality issues. Automation systems can also perform quality inspections that can help detect defects that may not be visible to the naked eye, such as microscopic cracks.

Types of sensors used in industrial automation

Among the most common types of sensor used in industrial automation are:

• Temperature sensors

Temperature sensors measure, monitor and control temperature in processes, materials and equipment. Examples include controlling the temperature of clean rooms and server rooms, monitoring the temperature of equipment and processes such as motors, pumps, chemical reactions and food processing, and maintaining optimal temperature conditions while minimising energy consumption.

• Pressure sensors

These sensors measure the pressure of gases and liquids in hydraulic and pneumatic systems, industrial pumps and compressors, as well as monitoring and controlling processes, and detecting leaks or blockages. In food processing, for instance, they can be used to monitor the pressure of steam used to sterilise equipment or pasteurize food products.

• Level sensors

Measuring the level of liquids and solids in tanks, silos or other containers, such as those commonly used in food and beverage production and wastewater treatment, requires level sensors. This allows for a more streamlined process and for the control system to be notified of any issues before they become critical.

• Position sensors

Robotics, conveyors and assembly lines are some well-known applications for linear and rotary position sensors . They are used to detect the position of objects, components, and equipment and provide real-time feedback, allowing for precise control and automation of industrial processes.

• Proximity sensors

These sensors detect the presence of objects within a certain distance and are commonly used to detect the presence of materials on conveyor systems, on assembly lines, and to monitor the position and movement of machine tools such as lathes, drills and milling machines. On an assembly line, for example, proximity sensors can detect the presence of parts and components, allowing for automated assembly processes where the parts are automatically positioned and assembled without human intervention.

• Force sensors

Force sensors are commonly used in industrial automation to measure and monitor the force applied to a surface or object, allowing for precise control. Applications include sensors to measure the force required to insert a component into a product, to test the strength and durability of materials, and for safety monitoring such as detecting overloads on hoists.

Sensor specification for industrial automation applications

While the selection of sensors will depend on the specific application and requirements, there are some general considerations and specifications that should be front of mind. These include the range, accuracy and response time of the sensor to ensure it can meet the demands of the application. The sensor’s output signal has to be compatible with the input requirements of the system’s controller, while its physical size and mounting method also has to be appropriate for the installation location. Many industrial environments are harsh, and so ensuring the sensor can provide accurate and reliable data, even when faced with a broad range of temperatures, humidity, vibration, dirt and dust is essential.

Sensors play a critical role in industrial automation by providing real-time data and enabling the automation of processes, thereby optimising manufacturing and increasing productivity. As technology continues to advance, we can expect to see even more innovative sensors being developed and integrated in to industrial automation systems. For help or advice on selecting the right sensor for your application, please get in touch with our team on +44 (0)1327 351 004, sales@variohm.com or by completing the Contact Us form on our website.