Safety is a top priority of any manufacturing facility. While every aspect of safety, from personal protective equipment (PPE) to physical designs such as fall protection, is important, modern facilities also need to prioritize safety considerations in control system design.
All facilities rely on technology and control systems for production, building systems, and management information and reporting. The application of automation has progressed significantly in recent years, leveraging readily available technology for overall production and business improvement. Control and automation implementation not only streamlines processes but is integral to the overall safety plan. It is crucial to include safeguards in your automation systems to prevent safety controls from being accidentally overwritten or disabled during normal facility operations. Below are some key considerations for increasing safety in industrial automation design.
Risk Assessment and Hazard Analysis
The first step in designing a safe automation system is to conduct a thorough risk assessment and hazard analysis. This process involves identifying potential hazards related to machinery, processes, and the environment. By understanding these risks, engineers can develop strategies to mitigate them. For instance, designing safe industrial panels requires meticulous attention to various aspects, including the following:
Component Selection: Choose safety-rated relays, sensors, and controllers, along with redundant, fail-safe components to ensure safe shutdown in case of failure.
Panel Layout: Label components and wiring for easy maintenance and safety. Maintain adequate spacing and ensure efficient ventilation to prevent overheating.
Wiring and Connections: Secure and route wires to prevent mechanical stress and short circuits. Use color-coded wiring for quick identification and troubleshooting.
Safety Device Integration: Add external safety features like emergency stop buttons, safety interlocks, and protective barriers hardwired outside PLCs to prevent accidental deactivation or overriding.
Environmental Considerations: Design the panel to ensure facility conditions like temperature extremes, humidity, dust, and corrosive substances.
Testing and Validation: Thoroughly test and validate the panel design to ensure safety features and components work correctly. Regularly test emergency stops, sensor calibration, and circuit continuity.
Safety Integration: To ensure industrial safety, integrate safety PLCs certified to IEC 61508 or ISO 13849. Choose PLCs with dual processors and self-diagnostics for real-time fault detection. Ensure they integrate seamlessly with emergency stops, safety light curtains, and interlocks. Regularly monitor performance, conduct maintenance, and update firmware/software to meet new safety standards.
The design of the Human-Machine Interface (HMI) is imperative for automation safety. A well-designed HMI provides operators with clear and intuitive controls, real-time feedback, and easy access to emergency stop functions. Proper training and clear instructions for operators help prevent human errors that could lead to accidents.
Incorporating safety features into the design of automation systems is a proactive approach to avoid accidents. This includes using safety-rated components such as safety relays, sensors, and controllers, which are designed to perform reliably under hazardous conditions. Additionally, systems should be designed with redundancy and fail-safe mechanisms so the system can safely shut down in the event of a failure. To prevent accidental deactivation or overriding of panel safety features during maintenance or daily operations, it is essential to add external safety features like emergency stop buttons, safety interlocks, and protective barriers. These external safety features should be hardwired outside of the automation panel so they cannot be overwritten.
Maintenance and Training
Regularly maintaining and inspecting automation systems is vital to certifying their safe operation. This includes routine checks of safety components, sensor calibration, and testing emergency stop functions. Preventive maintenance helps identify and address potential issues before they can lead to accidents. Promoting a safety culture within the organization is essential for the success of any safety program. This includes ongoing training for employees on safety procedures, emergency response, and proper use of automation systems and their safety features. Encouraging employees to report safety concerns and near misses can also help identify potential hazards and improve safety measures.
Conclusion
Safety in industrial automation design is a multifaceted approach that requires careful planning, adherence to standards, and continuous improvement. Conducting thorough risk assessments, incorporating safety features, designing intuitive HMIs, and promoting a safety culture can help organizations create a safer working environment. As automation technology evolves, prioritizing safety will remain a critical aspect of industrial automation design.
