Which safety standard might PLCs need to comply with?

PLCs, or Programmable Logic Controllers, are often used in safety-critical applications where ensuring operational safety is crucial. The safety standard IEC 61508 is specifically designed for the functional safety of electrical and electronic systems, including software implemented in programmable devices like PLCs. This international standard addresses the entire lifecycle of safety-related systems, focusing on risk assessment, hazard management, and the implementation of safety functions.

Compliance with IEC 61508 ensures that PLCs are designed, developed, and maintained in ways that minimize risks associated with system failures. This is particularly important in industries such as manufacturing, oil and gas, and transportation, where the consequences of failure can be severe. The standard provides guidelines for establishing safety integrity levels, which help organizations assess the necessary safety measures to mitigate risks.

Other standards listed, while beneficial in their own contexts, do not specifically address the comprehensive safety requirements and risk management of PLC applications as IEC 61508 does. ISO 9001 focuses on quality management systems, OSHA 1910 deals with occupational safety and health regulations, and ANSI Z535 is related to safety signs and symbols. While these standards are important in promoting overall safety and quality, they do not provide the direct safety compliance framework necessary for PLCs operating in safety-critical