What a design process looks like for Controls Engineers

The design process for controls engineers is a crucial step in developing automated systems and control solutions that ensure machines, processes, and devices operate efficiently, safely, and reliably. Controls engineers are responsible for designing, implementing, and optimizing control systems that regulate everything from industrial machinery to robotics. The design process they follow is methodical and systematic, ensuring that all technical, safety, and performance requirements are met. In this article, we will break down the typical design process that controls engineers follow to create effective control systems for various applications.

1. Problem Definition and Requirements Gathering

The design process begins with understanding the problem or need that the control system must address. Controls engineers collaborate with stakeholders, including project managers, operators, and other engineers, to define the requirements for the control system. This phase typically includes:

• Understanding the process ? Controls engineers first work to understand the industrial process or system they are designing the control system for. This could include everything from an automated production line to a HVAC system in a building. The engineer needs to understand the desired outcomes, such as temperature control, speed regulation, or position control.
• Gathering specifications ? Engineers collect technical specifications, including the types of machines and devices that will be controlled, the inputs and outputs required, and any performance or safety standards that must be met. This phase also involves identifying any constraints, such as energy consumption limits or physical space limitations.
• Defining control objectives ? The objectives for the control system, such as maintaining a setpoint (e.g., temperature or pressure), minimizing energy consumption, or maximizing production efficiency, are clearly defined. These objectives will guide the design of the control strategy.

At the end of this phase, controls engineers have a clear understanding of what the system needs to do, the constraints involved, and the specific requirements of the stakeholders.

2. Conceptual Design and Control Strategy Development

Once the problem and requirements are understood, the next step is to create a conceptual design for the control system. In this phase, controls engineers decide on the type of control strategy to be used, such as open-loop control, closed-loop control, or adaptive control, depending on the application. Key activities during this phase include:

• Control system architecture ? Engineers determine the architecture of the control system, including the types of controllers (e.g., PLC, DCS, or SCADA systems), sensors, actuators, and other components required. They decide how components will be connected and how data will flow through the system.
• Control algorithm selection ? Engineers select the appropriate control algorithms based on the application. For example, a proportional-integral-derivative (PID) controller might be chosen for temperature regulation, while a model-based predictive controller (MPC) might be more suitable for complex, multivariable systems.
• Simulations and models ? Before proceeding to full design, engineers often create mathematical models of the system and use simulation tools such as MATLAB, Simulink, or SimCAD to test and validate the control strategy. This allows them to predict how the system will perform under various conditions and optimize control parameters.

The conceptual design phase is critical because it lays the groundwork for how the control system will operate and ensures that the system will meet the desired objectives.

3. Detailed Design and Component Selection

In this phase, the conceptual design is turned into a detailed plan, specifying the exact components, materials, and technologies that will be used. Controls engineers select the appropriate hardware and software for the control system, ensuring that everything works together to meet the requirements. Key activities include:

• Component selection ? Controls engineers select components such as sensors, actuators, controllers, and communication devices. These components must meet the performance and safety requirements outlined in the specifications. For example, they may select a high-precision temperature sensor or a variable frequency drive (VFD) for controlling motor speed.
• Wiring diagrams and electrical schematics ? Engineers create detailed electrical schematics that show how the components will be connected, including wiring for sensors, actuators, and controllers. This ensures that all electrical connections are safe and meet industry standards, such as IEC 60204-1 for machinery safety.
• Software development ? In many cases, controls engineers will need to develop or program software to interface with the control system. This may involve writing code for PLCs, SCADA systems, or other control hardware. The software must ensure the system responds appropriately to inputs and operates within the specified parameters.

During the detailed design phase, engineers also begin to plan for the integration of the control system with existing systems or equipment, ensuring compatibility and smooth operation.

4. Prototyping and Testing

Once the control system design is complete, a prototype is built, and testing begins. This phase allows engineers to validate the control system and ensure that it works as intended before it is implemented in a full-scale production environment. Key activities during this phase include:

• Prototype construction ? Engineers build a prototype of the control system, using physical components or simulation tools. The prototype is tested under real-world conditions to ensure that it meets the design specifications and performs as expected.
• System testing ? The control system is tested to ensure that it operates safely and effectively. This includes verifying that it responds correctly to inputs, maintains the desired setpoints, and operates within specified limits. Engineers may also test for reliability and robustness by subjecting the system to extreme conditions.
• Optimization ? If issues are found during testing, engineers refine the control system by optimizing parameters, adjusting algorithms, or redesigning components. The goal is to fine-tune the system for maximum efficiency and performance.

Testing and prototyping are crucial steps in the design process, allowing controls engineers to identify any issues before the system is deployed in the field.

5. Installation and Commissioning

Once the control system has been validated through testing, it is ready for installation and commissioning. During this phase, the control system is integrated with the machinery or process it is meant to control. Key activities during this phase include:

• Installation ? Engineers oversee the installation of the control system, ensuring that all components are properly connected and that wiring and configuration are correct. This phase may involve on-site work and coordination with other engineering teams.
• System integration ? The control system is integrated with other systems, such as production machinery or robotics, to ensure smooth operation. Controls engineers work with other engineers and technicians to ensure that the system is properly calibrated and tuned for optimal performance.
• System validation and performance testing ? After installation, engineers conduct final performance testing to ensure that the system operates as intended. They check for any issues that may arise during normal operation and make adjustments to fine-tune performance.

Installation and commissioning are essential to ensure that the control system is properly integrated into the operational environment and functions as expected.

6. Ongoing Maintenance and Optimization

After the control system has been installed and commissioned, the work of the controls engineer is not complete. Continuous monitoring, maintenance, and optimization are essential to ensure that the system continues to operate efficiently and safely. Key activities include:

• Monitoring system performance ? Engineers monitor the performance of the control system, ensuring that it continues to operate within specified parameters. They may use SCADA or other monitoring tools to track system performance and detect any anomalies.
• Maintenance and troubleshooting ? Engineers perform routine maintenance on the control system, checking for wear and tear, cleaning components, and replacing parts as needed. They also troubleshoot any issues that arise, ensuring that the system remains reliable and efficient.
• Continuous improvement ? Controls engineers continually optimize the control system to improve performance, reduce energy consumption, and enhance product quality. They may implement software updates, hardware upgrades, or process changes to keep the system up to date and efficient.

Ongoing maintenance and optimization help ensure that control systems continue to perform at their best throughout their operational life.

Conclusion

The design process for controls engineers is a systematic and iterative approach to creating control systems that meet the requirements of safety, performance, and efficiency. From problem definition and conceptual design to prototyping, testing, and ongoing optimization, each phase is essential to ensuring that control systems function reliably and safely. By following this structured process, controls engineers contribute to the development of automated systems that drive innovation, improve productivity, and ensure the smooth operation of industrial processes across various industries.